UNIVERSITY OF NAIROBI

Transcription

1 UNIVERSITY OF NAIROBI GENERATION OF SURVEY PLAN FROM DEMARCATION PLAN: CASE STUDY OF MUKA MUKUU SETTLEMENT FARMS. By OGUTU KANGA STELLAMARIS F19/2553/2008 Supervisor: Mr. B.M Okumu A project report submitted to the Department of Geospatial and Space Technology in partial fulfillment of the requirements for the award of the degree of: Bachelor of Science in Geospatial Engineering APRIL/2013

2 Abstract Survey plan is one of the main ingredients produced by a Surveyor for land registration process in any society. Therefore, there is need for easier and proper ways of generating these plans, providing; accurate, reliable and efficient alternative ways of producing a survey plan. In most jurisdictions, the production of survey plans involves the cadastral surveying process which is the only means of obtaining Survey/Cadastral plans for fixed boundary survey according to the Survey Act. This project attempts to use the already existing demarcation plans of the whole area, which were produced by Muka Mukuu Farmers Society through both aerial survey and ground survey processes to come up with survey plan that meets all the requirements set by the Survey Act for a survey plan. The main strategy of this project is the salient control points identification and fixing for the whole area of the study. This was achieved by use of Real Time Kinematics (RTK) GPS that enabled high precision salient points to be established. Theses salient points later assisted in correctly georeferencing the demarcation plans hence resulting to a well controlled area for generation of survey plans. The demarcation plans were then converted to digital format by digitization of the scanned georeferenced plans by the help of Quantum GIS software. With the digital format of the well controlled plans, the production of the survey plan was achieved by the use of AutoCAD software. The survey plan produced were according to the stipulated regulations in that they had; coordinate list, actual ground distances, actual plot area, bearing of the distances and plot numbers. i

3 Dedication I dedicate this work to God and my Parents, for believing in me. I will always be grateful to them for facilitating my formal education. ii

4 Acknowledgements I wish to express my sincere gratitude to my supervisor, Mr. B.M. Okumu for his constructive guidance and inspiration throughout the project period. Special thanks to BOMA Survey Limited for their assistance and guidance during my attachment and project period. Heartfelt thanks also to my siblings, for their patience, love, financial support and spiritual backing during my 5 - year study at the university. Finally, I would like to thank the lecturers, students and staff of the Department of Geospatial and Space Technology for their support during my undergraduate studies at the university. iii

5 Table of Contents Abstract... i Dedication... ii Acknowledgements... iii Table of Contents... iv List of Figures... vi List of Tables... vii List of Abbreviations... viii CHAPTER ONE: INTRODUCTION Background Information Problem Statement Objectives General Objective Specific Objectives Scope of Study Organization of Report... 5 CHAPTER TWO: LITERATURE REVIEW Introduction Land Title Registration System under RTA Registration Process/Procedure Procedures or Methods of Registration under RTA Land Title Registration System under the RLA Procedure/Method of Registration under the RLA Demarcation Plans Aerial Surveying Ground Surveying GNSS Techniques of positioning RTK GPS Data Collection Data Post Processing Error Budget Why RTK GPS iv

6 CHAPTER THREE: METHODOLOGY Study Area Data Collection Data Identification Data Preparation Data Manipulation Scanning Data Conversion Georeferencing Digitization Generation of Survey Plan CHAPTER FOUR: RESULTS AND DISCUSSION Introduction Results Analysis Salient Control Points Distance Area Bearing CHAPTER FIVE: CONCLUSION AND RECOMMENDATION Conclusions Recommendations REFERENCES v

7 List of Figures Figure 1: Procedure in Cadastral Survey, (LIS in Kenya, 2001)... 3 Figure 2: The organization of the report... 5 Figure 3: Demonstration on carrying out RTK (Real-Time Kinematic) Figure 4: Illustration on Phase Differential Post-processing Figure 5: The geographic location of Muka Mukuu Settlement Farms Figure 6: Geographical representation of Muka Mukuu Settlement Farm Figure 7: Scanned demarcation plan of block Figure 8: Cropped section of the 13 plots Figure 9: Flow chart on methodology Figure 10: The georeferencing process Figure 11: The georeferenced plots Figure 12: Digitized plots Figure 13: Labeled plots Figure 14: A screen shot of the Survey plan Figure15: Complete representation of the survey plan vi

8 List of Tables Table 1: Horizontal precisions for various baseline lengths Table 2: Error Budget Table 3: The datasets and their sources Table 4: List of coordinates of the salient control points Table 5: A list of precision of the salient points vii

9 List of Abbreviations ACP: C.R: FIG: FR No.: Geo TIFF: GIS: GLA: GNSS: GPS: I.R: ITPA: JPEG: LIS: LR No.: LTA: NLRO: OTF: PDF: QGIS: RDA: RLA: RMS: RTA: RTK: SoK: UTM: XLS: Active Control Point Coastal Registry International Federation of Surveyors Folio Register Number Geo Tagged Image File Format Geographical Information System Government Lands Act Global Navigation Satellite System Global Positioning System Inland Registry Indian Transfer of Property Act Joint Photographic Expert Group Land Information Service in Kenya Land Reference Number Lands Title Act Natives Land Registration Ordinance On the Fly Portable Document File Quantum Geographical Information System Registration of Documents Act Registration of Lands Act Root Mean Square Registration of Titles Act Real Time Kinematics Survey of Kenya Universal Transverse Mercator Microsoft Excel Spreadsheet File viii

10 CHAPTER ONE: INTRODUCTION 1.1 Background Information One of the most important steps in land registration process involves the generation of survey plans that are usually produced by a land surveyor. The survey plans are usually produced through the process of cadastral surveying, according to the Land Registration Act (2012); A survey plan will show the boundary of the land parcel with the subdivision to be done and also a clear label of the area and distance of the fully controlled subplots. Related computations numbers and field note numbers are also indicated. Likewise computations will show the related F.R No. and field notes number and this goes to show how systematic crossreferencing of the cadastral records is. All the abutting plots of the newly numbered plot will be shown on the survey plan. After the documentation and the registration process is over in the records office, the newly registered survey plan, the computations and the field notes together with the correspondence files are forwarded to the Assistant Director Cadastral for checking. This project however uses the readily available Demarcation plans from Muka Mukuu Settlement farms to come up with the survey plans. The demarcation plans for this project was produced through aerial survey methods and ground survey methods, where aerial photographs of the entire area was taken and since people had already settled on the farms and fenced their properties, then it was easier to make machine plots of the area by tracing out the boundaries of the subdivision from the rectified photographs and the missing gaps filled in by chain survey process to come up with a complete demarcation of each settlement farm of the area. Therefore the demarcation plans produced through this process has the advantage of showing clearly the distance, bearing and area of each proposed subplots. By producing the survey plans through this process, one is able to make good use of the already existing demarcation plan which in other circumstances would be rendered useless; this on the other hand helps minimize the expense of field work for the production of survey plans through the rigorous cadastral surveying process and above all helps in the realization of the country s Vision 2030, and FIG vision of cadastre 2014 on end of paper and pencil maps. 1

11 1.2 Problem Statement This is a brief outlined procedure to be followed in a cadastral process, before a registration map or plan can be prepared. Specifications for execution of fixed boundary surveys are well laid out in the Survey Act. This is the servicing Act for the Land Registration Act 2012, that provide for fixed boundaries. A national control network, which in 1990 consisted of 1700 primary and secondary points covering nearly 70% of the country, forms the basis for fixed boundary surveys (Nyadimo. S.A., 1990). The surveys are carried out to measurable accuracy of (0.03m) to conform to planning requirements and the value of land. The parcel boundaries are defined by stable marks or visible features on the ground. These are represented by lines on maps often described by bearings or azimuths and distances, or by co-ordinates (International Federation of Surveyors, 1995). Physical demarcation on the ground is important because it provides actual notice of the boundaries to the landowners. The demarcation/delineation of the boundaries is a part of cadastral survey which aims at defining the parcel on the ground and providing security as evidence for the re-establishment of the boundary if it disappears. The survey fieldwork is undertaken by a Land Surveyor (defined in the Survey Act). This includes a surveyor working under the Director of Surveys or a licensed surveyor. He/she must carry out the cadastral survey in accordance with the regulations of the Survey Act e.g. the Survey Act stipulates the accuracy acceptable for each type of survey. The flow chart below shows the steps in performing cadastral survey. 2

12 PROCEDURE IN CADASTRAL SURVEYS Preparation of Topographical Sheets/Plans Preparation Preparation of Base of maps, Base Maps, Demarcation Demarcation plans and Plans Subdivision and subdivision Scheme scheme plan plan Approval of Development Plans Survey Fieldwork Based on Approved Plans Statutory Approval Sought by Surveyor Surveyor Implement the Scheme Layout on the Ground by Placing Boundary Corner Beacons Submission of Cadastral Plans to the Director of Surveys Checking Checking and and Authentication of Survey of Survey Plan by Plan the Director by the Director of surveys of surveys at at of survey Kenya of Figure 1: Procedure in Cadastral Survey, (LIS in Kenya, 2001) Once the above is done, the necessary statutory approvals are sought. This is in compliance with Regulation 30 of the Survey Act which states that: "Before submitting any survey to the Director of Surveys, a surveyor shall ensure that necessary approvals have been obtained for a subdivision or other transactions in any plot of land or in any case where such approval is required by any Act and the Survey submitted conforms to such approval." 3

13 This regulation implies that before embarking on the fieldwork, the surveyor must ensure that he has been provided with the necessary approvals. Once these are granted, the licensed surveyor is required to implement the scheme layout on the ground by placing the necessary boundary comer beacons. This process is as depicted by the Figure 1 above ((UN Habitat, 2001) As stated above it is clear that the production of survey plans usually involves rigorous cadastral survey process; so for this project all these tedious process elaborated is avoided in areas where there are existing Demarcation plans to come up with a Survey plan with its due specifications as stipulated in the Survey Act. 1.3 Objectives General Objective The main objective of the project is to generate Survey plans from readily available Demarcation plans. These survey plans are to assist in allocation of parcel numbers by Survey of Kenya for the subdivision of the large scheme owned by Muka Mukuu Farmers Co-operatives Society Specific Objectives The specific objectives of this project are to; 1. Scan the hardcopy demarcation plans. 2. Convert the data to GEOTIFF 3. Identify and pick the salient points from the ground using RTK GPS to be used in georeferencing. 4. Digitize the settlement farm subplots. 5. Prepare survey plan layout from the digitized subplots. 1.4 Scope of Study This project involves the generation of survey plans for the subdivision of the farm in Matungulu District, Machakos County, owned by the Muka Mukuu farmers co-operatives society. Its main focus is to assist in subdividing the two land parcels, initially at LR No and LR No of area acres and 521 acre respectively, before it was amalgamated to one land parcel of LR of area acres and subdivided into 2616 settlement farms for its members. 4

14 1.5 Organization of Report The report is divided into five chapters; Chapter One Includes detailed information on background information on generation of survey plans, problem statement, the objectives of the study and the scope of the study. Chapter Two Has the existing literature on the land registration production of demarcation plans and various methods of data collection Chapter Three This chapter explains the various techniques of data identification, acquisition and analysis that were adopted. Chapter Four In this the results obtained from the study and an analysis of the survey plans generated is examined for suitability and correctness. Chapter Five The final chapter consists of the conclusions and recommendations and analysis of the suitability of the results to be adopted for survey work. Figure 2: The organization of the report 5

15 CHAPTER TWO: LITERATURE REVIEW 2.1 Introduction Survey plan is a plan submitted to the Director of Surveys at the Survey of Kenya (SoK) for approval of any survey work done on any land parcel and finally assists in the land registration process. Registration is done in the Survey Records Office where all the survey data is stored. When the documents are received in the records office, they are entered in a register commonly known as the Green Register. The document is then given a unique number known as the entry number and for the first time, the document can be identified with that number. The survey plan is given the Folio Register (FR) number also from the green register. The number will depend on the size of the survey plan. (LIS in Kenya, 2001). The process of land registration considered in its totality starts with the establishment of the status of land. This entails the sequential steps of planning, allocation and survey of land to produce documents required to support registration and issuance of either title, deeds or certificate of leases. The maintenance and updating of the registers after the transactions in registration makes registration a dynamic and continuous process (Nyadimo S. A, 1990). Currently in Kenya, we have the deeds registration, in which records are transferred, the title registration system showing the evidence of a person s rights to property where the land parcel is the focus of the records and the private conveyancing system (Fervacque and Mcauslan, 1995). To achieve registration, the Registered Lands Act (RLA) (Cap 300) was enacted for the purpose of unifying the Registration of Titles Act (RTA), 1920 introduced the Torrens System of Registration and the Native Land Registration Ordinance (NLRO) of This was meant to convert customary tenure to individual tenure, based on the English System. Most plots registered under the Land Titles Act (LTA) have been converted to RLA titles. Those not converted to RLA are either in LTA if adjudicated before 1920 or under RTA if adjudicated in or after Under the RLA Land Certificates (for absolute ownership / freehold) and Certificate of Leases (leaseholds) are issued. Under the RTA Certificates of Title are issued which are conclusive proofs of title. Those given under RLA above are merely "prima facie" evidence 6

16 of title. They are issued on request after payment of a fee. When issued, they must be produced to the registrar every time one is registering the land in question (Jackson T. 1988). 2.2 Land Title Registration System under RTA The title registration in Kenya is determined by the RLA, RTA and the Sectional Properties Act. The RTA was enacted with the object of improving "issuance of titles" to land as well as transactions on the land for the benefit of the colonialists, apart from introducing a form of title registration based on the Torrens System, which also introduced conveyancing by statutory form. On introduction of RTA, all new successfully claimed plots were registered under RTA (Jackson T. 1988). Therefore the RTA was supposed to replace the registration provision of the Government Lands Act (GLA) and LTA. The registers kept under those Acts were to be convened on a voluntary basis, title for title. This was largely unsuccessful due to costs and the reluctance of landowners. It was the first Act that was meant to bring a simplified method of conveyancing in Kenya and more importantly, "a state guaranteed title" (Macoco D.K. 1999). It provided for the transfer of land by registration of titles. Unlike the Registration of Documents Act (RDA) which provided for the registration of documents without conferring any additional benefit, registration under this Act conferred on the landowner, an indefeasible title that is guaranteed by the State. It provided that all future grants of Government land and certificates of ownership of land at the coast be registered under it. Any landowner whose land was registered under the GLA or LTA would apply to the registrar to have his land registered under RTA in order to have the benefit of the state guaranteed title. It was expected that registration under the earlier Acts would eventually be phased out so that in future, all land in the country would come under the umbrella of one Act. Re-registration was however not made compulsory under the Act. Consequently, a number of landowners chose not to seek re-registration. Land registration under the three Acts above, continue side by side Registration Process/Procedure For every instrument presented for registration under the Act a fee is charged. This starts with the submission to the registry of the first document of title by which ownership of a piece of land is initially conferred on a person. The first document with deed plans attached which could be a Grant or Certificate of Tide is given a registration reference number prefixed 7

17 Inland Registry (I.R) for all upcountry land and Coast Registry (C.R) for all coastal land. Registration under the Act is undertaken in Nairobi and Mombasa. A copy of the document is retained in the registry and the original returned to the owner. Both the original and the copy are sealed with the Registry Seal. The copy retained at the registry constitutes the register for that piece of land and all subsequent documents relating to the land are endorsed on that document. Whenever any document is submitted for registration, it has to be accompanied by the original title held by the landowner, which is a1so endorsed in the registry. Therefore, it is possible at a glance to tell who the owner of the land is and all transactions relating to the parcel or the initial grant Procedures or Methods of Registration under RTA i. Surveys are carried out to standards of precision to be able to have boundaries that are coordinated. Generally, this is to the nearest 0.01m using theodolites and steel tapes. ii. Points are fixed by bearing and distance measurement or equivalent techniques and tied to control traverses. The main titles registration Acts widely applying at present in Kenya are the RLA and RTA. The introduction of the RTA resulted in all new successfully claimed plots being registered under the RTA (Jackson T, 1988). Every grant of land under this Act must contain a diagram of the land on such a scale as maybe directed by the Commissioner of Lands. This act superseded the registration provisions of the LTA, it is a more precise Act utilizing fixed boundary of the 1908 LTA. Some argue that the registration of titles is a more efficient method for conveyancing of land leading to fewer disputes (Dale P.F. and McLaughlin J.D., 1988). When one needs to have the boundaries registered as fixed, they apply for this. Section 22(2) of the RLA is then used which states that the Registrar determines from whatever evidence he considers relevant, the position of the boundaries. These are then surveyed and the plan filed which is deemed to define accurately the boundaries of the parcel. All land held under RTA can be brought under RLA without any change in the fixed nature of the boundaries. Under RLA registration, information on each parcel of land is kept in a 8

18 register in the Registration Section. Each register is divided into three sections which are the; property, proprietorship and encumbrance sections. 2.3 Land Title Registration System under the RLA Before registration can be effected under RLA, unless a conversion has been done bringing Titles that were already registered under the statutes of RLA, adjudication or sometimes both adjudication and consolidation are required (Jackson T, 1988) Procedure/Method of Registration under the RLA The process begins after evidence of ownership of the piece of land is ascertained: a) Preparation of a map called the Registry index Map in which al pieces of land in an area are shown and numbered. b) Each parcel or land is known as a parcel (Cadastre). c) For each parcel, a form of ledger card (register) is opened in which details of land such as the size, ownership and encumbrances are shown. Under the act, the opening of the card constitutes the first step in land registration. d) There are two categories of cards: i. Freehold (green in color) ii. Leasehold (white color) The register as described above is the document, which is the final authority on the ownership of the land or lease and all transactions affecting it. District Registers are established under RLA. Apart from the Register, all Land Registries or Index Map are prepared by the Director of Surveys in accordance with the provisions of the Survey Act and the RLA. Each plot is described by reference to its serial number which is a combination of its district, section, block and parcel number. Under the RLA register, each parcel of registered land has its own register supported by a registry index map. Separate registers are kept for each lease. When a lease is granted, a new leasehold register is opened. However, the old register is maintained, as the right of reversion remains vested in the absolute proprietor. The registers and lease registers are divided into the Property section which contains the name and address of the proprietor, the proprietor section which also contains any inhibitions, caution, or restriction affecting the proprietor s right of disposition, and the encumbrance section that s a note of every encumbrance and every right 9

19 adversely affecting the land or lease e.g. details of any charges and leases. (Jackson T. 1988). The register is in the form of a ledger and therefore the sheets can be taken out and put back. Whenever transactions are entered, there is always a supporting document, which gives details of the transaction. Consequently, each register has its own Parcel file where all supporting documents arc kept. There is also a Presentation Book in which is recorded the date and the time of day when the application for registration is first made in the registry for the purpose of determining the priority of application and showing precisely what applications come into the registry. Unlike the GLA, RTA and LTA, that require that all titles and documents transferring subdivision to be attached to a survey deed plan of the piece of land in question, the RLA requires a map to be prepared. The proof of absolute ownership is the Title Deed given to an owner registered under RLA. Certificate of lease is the proof of a leasehold interest for any given parcel. Only one title deed or certificate of title is given. Once new owners take over the old title deeds the certificates of the title have to be retrieved and destroyed. The Title deed and Certificate of Lease is merely evidence of what is shown in the register at the time it is issued. It is the register and the entries kept in the land registries, which matter. When there are any subsequent dealings on the land, the title deed and the certificate of lease must henceforth be produced. Under the RLA the rights of the proprietor are fundamental whether acquired on first Registration or as a result of a subsequent transaction or by an order of court and cannot be defeated except as specifically provided for in the Act. They are free from all claims and interests but are subject to any entries on the register and to overriding interests. Currently, land parcels registered under GLA are not re-registered under GLA on the expiration of the leasehold. Instead they are converted and registered under RLA; Indian Transfer of Property Act (ITPA) therefore ceases to apply to them (Onalo P.L, 1986). Section 12 (i) and (ii) of the RLA provides that the title to parcels of land composed under a Certificate of Title or grant under RTA shall be registered under the RLA. However, the land registrars in Mombasa and Nairobi have to search and sort out existing registers under RLA. According to (Onalo P.L, 1986), many blocks in the Mombasa Island have been converted 10

20 and are now under RLA. Eventually the Act is supposed to systematically apply to areas which LTA, GLA, and RTA hitherto applied. In addition, the register of powers of attorney kept under GLA, LTA and RTA are deemed to be registers of powers of attorney under the RLA where the titles under these Acts have been convened to RLA titles. 2.4 Demarcation Plans Demarcation is a plan prepared to assist in locating the general extents of the boundary of any land parcel. They are prepared by a surveyor to assist in planning for the subdivision of a land parcel. It is usually prepared by use of aerial photographs with the assistance of ground surveying. Through these processes it was possible to achieve 20 sheets of maps covering the whole area owned by the Muka Mukuu Society at a scale of 1:5000 and later updated by chain survey to obtain 11 sheets of demarcation plans Aerial Surveying Aerial surveying process involves the photogrammetric process whereby, Photogrammetry is an art, because obtaining reliable measurements requires certain skills, techniques and judgments to be made by an individual. It is a science and a technology because it takes an image and transforms it, via technology, into meaningful results. Modern Photogrammetry includes image sources and image forms other than photographs, such as radar images. The photogrammetric process consists of project planning, image acquisition, image processing, and data control for image orientation, data compilation and presentation of an end product. The end product of the photogrammetric process can be coordinate values of individual points, a graphic representation of the ground surface (topographic map), or a rectified image of the ground surface with map-like characteristics (orthophoto.) (New Jersey State Survey manual, 2012) The process of aerial surveying that was undertaken by the Muka Mukuu Farmer s Society involved the process of aerial photography whereby the photographs were taken of the whole area. Since the area had already been settled on and fenced out by trees, it was easy to trace out the extent of the plots and generate a map of the area. 11

21 By use of machine plots, the errors due to exterior and interior orientation were eliminated hence making the trace out to be a true reflection of the ground. The end result of the process resulted to a 20 sheets of maps at a scale of 1:5000 that contained; Physical features on the ground Contours Abuttal Plot numbers according to the 20 blocks covered by the map sheets Ground Surveying The survey fieldwork is undertaken by a Land Surveyor who is defined as a surveyor working under the Director of surveys or a licensed surveyor according to the Survey Act. This process was carried out through chain surveying process and it was necessary so as to assist fill in the gaps in the machine plots created from the aerial surveying process. Through this process that the two surveying processes are complimenting each other help to produce a better plan for the area. 2.5 GNSS Over the past years Global Navigation Satellite System (GNSS) reference networks have simplified and extended the range of high-precision positioning over longer distances with the aid of differential corrections, including those provided by so-called virtual stations. However, a number of operational and environmental factors including accurate and timely characterization of local ionospheric and tropospheric conditions continue to limit the full realization of these techniques potential. Access to and use of additional satellite signals from multiple GNSS systems could help address these limitations. Among the candidate combinations are the use of signals from the U.S. Global Positioning System (GPS), Russia GLONASS, China BEIDOU and the European Union Galileo system now under development. Without question GPS has revolutionized precise positioning since its advent. Real-time methods to quickly fix carrier phase integer ambiguities, the key to precision, have been developed and are often referred to as Real Time Kinematics (RTK) techniques. RTK is an advanced manifestation of the principle of differential positioning; a method that requires at 12

22 least one reference station with known coordinates to simultaneously track GNSS satellite signals. Carrier phase measurements are used in addition to pseudoranges due to their superior accuracy. (Inside GNSS Working Paper, Nov\Dec 2007) Techniques of positioning The techniques include differential (Relative positioning) and Absolute Positioning as discussed below; Differential (Relative) Positioning Differential or relative positioning requires at least two receivers set up at two stations (usually one is known) to collect satellite data simultaneously in order to determine coordinate differences. This method will position the two stations relative to each other (hence the term relative positioning ) and can provide the accuracies required for basic land surveying and hydrographic surveying. They include; a. Static. Static surveying is the most widely used differential technique for control and geodetic surveying. It involves long observation times (1-2 hr, depending on number of visible satellites) in order to resolve the integer ambiguities between the satellite and the receiver. Accuracies in the sub centimeter range can be obtained from using the static method. b. Rapid static. The concept of rapid static is to measure baselines and determine positions in the millimeter level with short observation times, 5-20 min. The observation time is dependent on the length of the baseline and number of visible satellites. Loss of lock, when moving from one station to the next, can also occur since each baseline is processed independent of each other. c. Kinematic. Kinematic surveying, allows the user to rapidly and accurately measure baselines while moving from one point to the next. The data are collected and post-processed to obtain accurate positions to the millimeter level. This technique permits only partial loss of satellite lock during observation and requires a brief period of static initialization. The on-the-fly (OTF) technology, both real-time and post-processed, could eventually replace standard kinematic procedures at least for short baselines. d. Stop and go kinematic. Stop and go kinematic involves collecting data for several minutes (1-2 min.) at each station after a period of initialization to gain the integers. This technique does not allow for loss of satellite lock during the 13

23 survey. If loss of satellite lock does occur, a new period of initialization must take place. This method can be performed with two fixed or known stations in order to provide redundancy and improve accuracy. e. Pseudo-kinematic. This technique is similar to standard kinematic procedures and static procedures combined. The differences are that there is no static initialization, longer period of time at each point (approximately 1-5 min), each point must be revisited after about an hour, and loss of satellite lock is acceptable. The positional accuracy is more than for kinematic or rapid static procedures, which makes it a less acceptable method for establishing baselines. f. RTK and OTF carrier phase based positioning determination. The OTF/RTK positioning system uses GPS technology to allow the positioning to a sub decimeter in real time. This system determines the integer number of carrier wavelengths from the GPS antenna to the GPS satellite, transmitting them while in motion and without static initialization. The basic concept behind the OTF/RTK system is kinematic surveying without static initialization (integer initialization is performed while moving) and allows for loss of satellite lock. Other GPS techniques that can achieve this kind of accuracy require static initialization while the user is not moving and no loss of satellite lock while in motion Absolute Positioning GPS was originally conceived and designed to provide point positioning and velocity of a user with a single, usually low-cost, hand-held GPS receiver. This is termed as "absolute" or "autonomous" point positioning, as distinguished from "relative" positioning when a second receiver is employed. GPS absolute or autonomous positioning is the most widely used military and commercial GPS positioning method for real-time navigation and location. It is usually not sufficiently accurate for precise surveying, mapping, or hydrographic positioning uses. a) Absolute or Autonomous Point Positioning. - Absolute/autonomous positioning involves the use of only a single passive receiver at the user s location to collect data from multiple satellites in order to determine the user's georeferenced position. GPS determination of a point position on the earth actually uses a technique common to terrestrial surveying called trilateration--i.e. electronic distance 14

24 measurement resection. The user's GPS receiver simply measures the distance (i.e. ranges) between the earth and the GPS satellites. The user's position is determined by the resected intersection of the observed ranges to the satellites. At least 4 Satellite ranges are required to compute a 3-D position and resolve timing variations between the satellite and receiver clocks. Adding more satellite ranges will provide redundancy (and more accuracy) in the position solution. The resultant 3-D coordinate value is relative to the geocentric reference system (WGS84). The GPS receiver may be operated in a static or dynamic mode. The accuracies obtained by GPS absolute/autonomous positioning are dependent on the user's GPS receiver quality, location, and length of observation time, Dilution of Precision (DOP), and many other factors. b) GPS Absolute or Autonomous Position Solution Process - Pseudoranging. When a GPS user performs a navigation solution, only an approximate range, or "pseudorange," to selected satellites is measured. In order for the GPS user to determine their precise location, the range to the satellite must be measured and the position of those satellites must be known. By pseudoranging, the GPS user measures an approximate distance between the GPS antenna and the satellite by correlation of a satellite-transmitted code and a reference code created by the receiver. This measurement does not contain corrections for synchronization errors between the clock of the satellite transmitter and that of the GPS receiver. The distance the signal has traveled is equal to the velocity of the transmission multiplied by the elapsed time of transmission. The signal velocity is affected by tropospheric and ionospheric conditions in the atmosphere (Introduction to the Global Positioning System for GIS and TRAVERSE, June 1996) RTK GPS Data Collection RTK involves the use of 2 GPS receivers (stationary Base Station and a Rover) communicating together via a radio link. The base station must be located such that it will have a clear view of the sky and a continuous line-of-sight to the rover. The precision of the Rover position relative to the Base station is dependent on baseline-length so it is desirable to keep the baseline as short as possible. 15

25 RTK performs Real Time Phase Differential and computes the 3D vector ( X, Y, Z) between the rover and base antenna. Base Station coordinates and both antenna heights need to be entered to compute ground coordinates at the Rover. Figure 3: Demonstration on carrying out RTK (Real-Time Kinematic) Data from the Base Station (either raw GPS data or RTK corrections) is sent in real time via radio to the Rover. With a sufficient number of common satellites visible at both GPS antennas, a FIXED solution of centimeter-level precision can be calculated. If there are insufficient common satellites, a FLOAT solution of lower precision (a few decimeters) is calculated. You can try waiting for a FIXED solution or re-initializing the system but these may not be successful as most often the FLOAT solution is due to poor satellite visibility at the Rover. RTK systems are available in dual-frequency and single-frequency versions. Dualfrequency systems deliver greater precision, faster and over longer baselines than singlefrequency systems. The choice of equipment depends on budget, expected baseline lengths and precision needs. Here are typical horizontal precisions (RMS) you can expect for various baseline lengths under ideal conditions as shown in the table 1: 16

26 Horizontal precisions for various baseline lengths 1 km 10 km 30 km Dual-Frequency ~ 0.1 cm ~ 0.2 cm ~ 0.5 cm Single-Frequency ~ 0.2 cm ~ 0.5 cm Too long Table 1: Horizontal precisions for various baseline lengths Data Post Processing It is recommended (but not essential) to have Phase Differential Post-Processing software. If the Rover loses radio-communication with the base (due to an obstruction or to excessive distance), you could still produce corrected Rover positions by post processing. Set the base station to record raw GPS data during the entire RTK survey. If the rover loses the radio link, record raw data at the rover and perform Phase Differential Post-Processing along with the base station raw data. Figure 4: Illustration on Phase Differential Post-processing Phase Differential Post-Processing could be used alone instead of RTK to do a site survey (it s the same GPS equipment minus the radio link) however the user would lose the advantages of RTK (feedback on equipment performance and final results in real-time). 17

27 2.5.4 Error Budget The GPS system has been designed to be as nearly accurate as possible. However, there are still errors. Added together, these errors can cause a deviation of +/ meters from the actual GPS receiver position. There are several sources for these errors, the most significant of which are discussed below: Atmospheric Conditions - The ionosphere and troposphere both refract the GPS signals. This causes the speed of the GPS signal in the ionosphere and troposphere to be different from the speed of the GPS signal in space. Therefore, the distance calculated from "Signal Speed x Time" will be different for the portion of the GPS signal path that passes through the ionosphere and troposphere and for the portion that passes through space. Ephemeris Errors/Clock Drift/Measurement Noise - The data concerning ephemeris errors may not exactly model the true satellite motion or the exact rate of clock drift. Distortion of the signal by measurement noise can further increase positional error. Selective Availability (SA) - Is the intentional alteration of the time and ephemeris signal by the Department of Defense. Fortunately, positional errors caused by SA can be removed by differential correction. Multipath - A GPS signal bouncing off a reflective surface prior to reaching the GPS receiver antenna is referred to as multipath. Because it is difficult to completely correct multipath error, even in high precision GPS units, multipath error is a serious concern to the GPS user. The table below lists the most common sources of error in GPS positions. This table is commonly known as the GPS Error Budget: 18

28 Source Uncorrected Error Level With Differential Ionosphere 0-30 meters Mostly removed Troposphere 0-30 meters All removed Measurement Noise 0-10 meters All removed Ephemeris Data 1-5 meters All removed Clock Drift meters All removed Selective Availability 0-1 meter All removed Multipath 0-70 meters Not removed Table 2: Error Budget (Introduction to the Global Positioning System for GIS and TRAVERSE, June 1996) Ambiguity in the resolution is only possible as long as the users (the roving receiver ) is located in the vicinity of this reference station let us say, within a radius of approximately 25 kilometers. Within this short range the benefits of the often-employed double differences technique can be effectively exploited: Differences of observations between a primary and a secondary satellite are formed on both the rover and the reference site and these two quantities are then subtracted, yielding a derived measurement between both sites that is free of satellite and receiver clock offsets or errors. Fortunately, the atmospheric errors are spatially correlated and can be reduced in the double difference measurements to a reasonable extent. Thus, it is relatively easy to fix ambiguities of short baselines, whereas it becomes increasingly difficult to do so over longer baselines due to decorrelation of the atmospheric delays. As a result of this decorrelation, the service area of conventional RTK systems allowing for quick ambiguity fixing covers about 300 square kilometers. The solution for this problem: Use multiple reference stations to derive atmospheric corrections. Because the coordinates of these fixed stations can be determined precisely or can be treated as tight constraints the atmospheric (ionospheric and tropospheric) effects on GNSS signal propagation can be derived from the correlated data. These station-, baseline-, or satellite-specific corrections can 19

29 be interpolated at the rover site. Hence, atmospheric errors can be significantly reduced and GNSS reference networks can substantially increase the distance between stations while still providing the accuracy level on conventional RTK systems. The reference networks that provide such correction data are often called active GNSS networks, referring to their Continuously Operating Reference Stations (CORS). Most of them offer both real-time and post-processing services. CORS provides GNSS data that consist of carrier phase and code range measurements in support of three dimensional positioning, meteorology, space weather, and geophysical applications throughout its territories. (National Geodetic Survey, Jan ) By adding to the number of satellite signals available to these networks, users on the road/in the field can improve their performance by allowing optimization of satellite geometry (the selection of a subset of available signals that reduces the dilution of precision (DOP) factor), use of multiple frequencies for carrier phase integer ambiguity resolution, and for achieving so-called over determined solutions. With multiple GNSS systems under development in addition to GPS that are increasingly compatible or even interoperable, this prospective approach is becoming ever more attractive. (Inside GNSS Working Paper, Nov\Dec 2007) Why RTK GPS RTK GPS was most preferred for data collection for this project because of its high precision level in salient point determination which in turn increases the precision of generation of Survey Plan from the demarcation plans, since with high precision of the salient points, this makes the area and bearing of the plots obtained to have high precision too. 20

30 CHAPTER THREE: METHODOLOGY 3.1 Study Area Muka Mukuu Farmers Cooperative Society Limited is located in Matungulu district, Machakos County. The land was initially a ranch owned by Lord William Northrop Macmillan born in 1872 and later died in He was a decorated American soldier and knighted by the King of England. He arrived in Kenya in 1901 for big game hunting. He also played host to former US President Theodore Roosevelt, during his famous 1911 safari at their ranch. He and his wife were great philanthropists; they established the MacMillan Library in central Nairobi. (Wikipedia, 2012) Figure 5: The geographic location of Muka Mukuu Settlement Farms 21

31 Figure 6: Geographical representation of Muka Mukuu Settlement Farm The land initially covered two land parcels of LR No and LR No of area Ha and Ha respectively, which were later amalgamated to one land parcel of LR No of approximate area of Ha. This resulted to one large parcel of land that was however of lesser area because of the gentle mans agreement between the Society and the Kenya Wildlife Services. This land surrounds Ol Donyo Sabuk Hill and on the Western part of the farm there is the Athi River, which leads straight to the fourteen falls to the Northern part of the settlement farm. The farmers cooperative was formed so as to buy land from the original owner, Lord MacMillan. The word Muka Mukuu is a Kamba word which means the first wife; hence for this purpose the land was allocated only to the first wife of each household according to the shares each one has in the cooperative. According to the proposed consolidation and subdivision plan the land was changed from an agricultural land to; i settlement farms ii. 11 Primary Schools of 4.1 Ha iii. 3 Secondary Schools of 4.1 Ha 22

32 iv. 20 Nursery Schools of 4.1 Ha v. 17 Dams of 4.1 Ha vi. 13 marked centers of Ha vii Commercial Plots of Ha viii. 51 Church Plot of Ha ix. 4 Cattle Dips of 4.1 Ha (Letter from the County Council of Masaku, 1995) But for the sake of this project we only generate the survey plans of the settlement farms which had an area ranging from 4 Acers to 8 Acers depending on its physical features on it. 3.2 Data Collection Data Identification The table shows the various datasets that were used in this study and their sources. DATASETS Demarcation Plans Coordinates of salient control points SOURCES BOMA Surveys Limited Field collection by RTK GPS Table 3: The datasets and their sources Datasets and Sources Demarcation plans acquired were in the form of hardcopy paper plans which had to be scanned for ease of use in softcopy format in all the available softwares. For the purpose of georeferencing we had to obtain salient points of the area through field measurement of the area by use of RTK GPS; the process involved setting the base at the top of Ol Donyo Sabuk Hill for ease of communication in all direction of the vast area of Muka Mukuu settlement farm by the rover. 23

33 3.2.2 Data Preparation Data used in the study were prepared as follows: Geographical Data In this study area, the geographical data were the scanned demarcation plans of the whole area which is a combination of 11 sheets. It also includes the list of coordinates of all the salient points acting as control points that were used in the georeferencing process. The following is; 1. A graphical representation of the demarcation plan for block 10. Figure 7: Scanned demarcation plan of block 10 Since the clarity of the image used is compromised by the large area of coverage so for the sake of this project only 13 plots of block 10 were used to demonstrate the process of generating survey plans. The figure below shows the cropped section of the 13 plots from the demarcation plans. 24

34 Figure 8: Cropped section of the 13 plots 2. A list of coordinates of the salient control points POINT NORTHINGS EASTINGS NAME OF BEACON CLASS OF BEACON NW62 A.I.C SE60 A.I.C DLIND A.I.C MW A.I.C AN A.I.C NE1530 A.I.C OF A.I.C AX A.I.C Col.19 A.I.C A A.I.C Old B A.I.C Old C A.I.C Old D A.I.C Old POST A.I.C Old T5 A.I.C Old B New A.I.C Re-established Q A.I.C Old 25

35 MUTURI A.I.C Old MM1 A.I.C New ERP A.I.C Old P4 A.I.C Old MUTHII A.I.C Old P3 A.I.C Old A New A.I.C Old donyosabuk ecg I.P.C Old BLK10-1 I.P.C Old BLK10-4 I.P.C Old BLK10-5 I.P.C Old BLK10-6 I.P.C Old BLK I.P.C Old BLK10-7 I.P.C Old BLK5-1 I.P.C Old BLK5-2 I.P.C Old BLK5-3 I.P.C Old BLK5-5 I.P.C Old BLK7-1 I.P.C Old BLK7-kiboko I.P.C Old sapuk top I.P.C Old donyosabuk eci I.P.C Old Block 7 Dam 1 I.P.C Old Block 7 Dam 2 I.P.C Old Block 12 kitambaasye I.P.C Old Kisitimani 1 I.P.C Old kwa mulinga I.P.C Old workshop I.P.C Old dr mulinga I.P.C Old Muhindj I.P.C Old donyo road I.P.C Old Table 4: List of coordinates of the salient control points 26

36 3.3 Data Manipulation THE METHODOLOGY Scanning of Demarcation Plans Data Conversion Georeferencing NO RMS error acceptable? YES Digitization Generation of Survey Plan Figure 9: Flow chart on methodology 27

37 3.3.1 Scanning The first step of this project involved scanning of the Demarcation plans which automatically captures the plan features, text and symbols as individual cells, or pixels and produces an automated image. The scanned file shows plan features as raster lines (a series of connected pixels). This process enabled conversion of the hardcopy data to softcopy for ease of data manipulation Data Conversion Since the data obtained were in different format i.e. PDF and JPEG they had to be converted so as to be compatible with QGIS. Great care and attention had to be given to this particular process so as to realize accurate data conversion and transfer. This conversion process was done by the help of Global Mapper software where all the raster data were converted to GeoTIFF format that could easily be manipulated in QGIS Georeferencing The next step involved georeferencing of the plans in Global Mapper with the assistance of the various salient points that could be identified both on the ground during the collection process and on the plans. The coordinate reference system that was used for this process was; Projection as UTM Datum as Arc 1960 Planar Unit as Meters Zone as 37 o East 28

38 Figure 10: The georeferencing process The RMS error that accumulates during the georeferencing process was 1.56 and for this work under requirement of the Land Act, 2012 the error limit of a survey plan should be below 0.03m hence was not acceptable so the process was repeated. After several iterations, the RMS error was 0.00, which was acceptable allowing room for digitization. The georeferenced plans obtained was. 29

39 Figure 11: The georeferenced plots Digitization Digitization is the conversion of analogue data to digital data by a variety of techniques. For this project, we proceeded to digitize the various settlement plots by the help of QGIS software. The resulting digitization of the 13 plots is as shown below Figure 12: Digitized plots 30

40 Thereafter the plots were well labeled indicating correctly the areas and distances also index to the adjoining plots. This was done in AutoCAD since the writings could be aligned easily in AutoCAD as compared to QGIS as shown below; Figure 13: Labeled plots Generation of Survey Plan The final survey plan for this project was generated using AutoCAD 2007 Land Development software where the digitized area was demarcated to show all the plots, beacons, distances, bearings, plot numbers and area as required for a survey plan. The grid of the whole area at intervals of 100m was also shown to give the general positioning of the plots which were referenced to UTM projection and Arc 1960 datum. Also as a requirement for survey plan drawing the adjacent plots were also indicated and their plot numbers given. As a requirement for a survey plan some marginal information had to be included to show the list of coordinates of all the salient points used and the corner beacons at the upper left corner of the plan while the upper right showed the list of bearings that could not fit in the subplots, 31

41 on the bottom of the plan there is the certification clause by the Licensed surveyor that the field work done by his/her assistant was according to his guidance and below it is the certification of the assistant that the work done was according to the set regulations. Next to the certification clause is the table for registration, transaction and authentication of the plan. The figure 14 below shows a demonstration by a screen shot of the generated survey plan from AutoCAD 2007 Figure 14: A screen shot of the Survey plan 32

42 CHAPTER FOUR: RESULTS AND DISCUSSION 4.1 Introduction This chapter provides the results achieved from the project. Analysis of the plans generated is examined for suitability and reliability and a comparison of the results is also done to check on the suitability of the results vis a vis the usual methods of generating survey plans. 4.2 Results The end result of this project consists of a Survey Plan with all the requirements as stipulated in the Survey Act. Figure15: Complete representation of the survey plan 33