Durham E-Theses The development of geographical information systems for the 1989 kenya population census Mwangangi, Isaac Kioko How to cite: Mwangangi, Isaac Kioko (1990) The development of geographical information systems for the 1989 kenya population census, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/6145/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 The Development of Geographical Information Systems for the 1989 Kenya Population Census by Isaac Kioko Mwangangi Thesis submitted for the degree of Master of Arts October 1990 University of Durham (Department of Geography) The copyright of this thesis rests with the author. No quotation from it should be published without his prior written consent and information derived from it should be acknowledged. '"' ,., -:~ 1 7 \,._, · . .J' !-' THESIS THE DEVELOPMENT OF GEOGRAPHICAL INFORMATION SYSTEMSFOR THE 1989 KENYA POPULATION CENSUS Abstract This thesis evaluates the potential of geographic information systems (GIS) technology for possible introduction into the analysis of the population census of Kenya. It does so from a starting point of no digital mapping being used at present, and no staff trained in the technology. The one year research programme had a number of aims which would underwrite a fuller evaluation of GIS back in Kenya; to (i) evaluate the training implications in GIS. (ii) evaluate the quality and usefulness of base maps produced by the Kenya Statistics office, with a view to automating them for subsequent digital mapping. (iii) achieve capability and understanding of concepts in the process largely referred to as "digital mapping". The 1989 census was the first to map the country to the level of Villages which are small subdivisions of the Sub-Locations. Enumeration Areas were based on these Villages. The 1989 census field work was the most detailed of all previous censuses. About 4000 Sub-Location maps or Enumeration Area maps were prepared for the census. They were used to produce the required copies for the Enumerators and Supervisors who participated in the census enumeration. The preparation of the District maps for digitising e.g. tracing, identifying and fixing reference points; digitising and editing the coverages; transforming the coverages; and updating the coverage data files took approximately five months. Using this database a population density map was produced. The study has proved the feasibility of full computer mapping for the analysis of the 1989 Kenya population census. It provides a basis for the development of a full GIS capability. Further, the cartographic information from Kenya, while having limitations, has been combined and integrated to provide a national coverage. Census data, already in the computer form, are relatively easily integrated into the GIS database. NOTES Figures 9.8, ~' 9.11, 9.12, 9.13, 9.14 and 9.17 are in a separate folder. 1 CONTENTS Notes 1. Chapter 1- Introduction ......................... 1 1.1 Background . ........................................ 1 1.2 Kenya and its census ............................... 2 2. Chapter 2 - Examining the need for census geographical preparatory work with reference to the 1989 Kenya population census ................ 9 2.1 Introduction ........•.............................. 9 2.2 The history of census population in Kenya .......... 9 2.3 The need for census geographical preparatory work .............................................. 14 2.4 The problems faced by the Developing Nations ....... 15 2.5 The 1989 population census geographical preparatory work . .................................. 17 2.5.1 Cartographic Organisation •...•..................... 18 2.5.2 The census geographical frame ....•................. 22 2.5.3 Census base maps . .................................. 2 5 2.5.4 Determining the census mapping activities .......... 27 2.5.5 Preparation of various listing and control forms ... 28 2.5.6 Procurement of materials and equipment ............. 30 2.6 Conclusion . ........................................ 31 3 Chapter 3 - Developing a methodology for field mapping . ........................................... 3 3 3.1 Introduction ....................................... 3 3 3.2 Field trip to Transnzoia and Taita Taveta Districts . ......................................... 3 6 3.3 Field trip to Garissa •.....•....................... 38 2 3.4 Field trip to West Pokot and Kakamega Districts . ......................................... 41 3.4.1 Talau Sub-Location ................................. 41 3.4.2 Kisatiru Sub-Location .............................. 43 3.5 Recommendations based on the field tests ........... 46 4. Chapter 4 - The cartographic field work for the 1989 population census ............................. 48 4 . 1 Introduction . ...................................... 4 8 4.2 Workshops for the field mapping staff .............. 49 4.3 Organisation of the field mapping exercise ......... 53 4.4 Updating the base maps and delineating enumeration areas .................................. 58 4.4.1 Enumeration areas. What are they ? ................. 63 4.4.2 Obtaining population estimates ..................... 67 4.4.3 Mapping areas with dense population ................ 71 4.4.4 Mapping enumeration areas in Urban centres ......... 75 4.4.5 Mapping areas with sparse population ............... 81 4.4.6 Mapping enumeration areas in the National Parks .... 84 4.4.7 Treatment of special areas ......................... 84 4.4.8 Symbols used during the field mapping .............. 85 4.4.9 Numbering the enumeration areas .................... 87 4.4.10 Large enumeration areas ............................ 88 4.4.11 Sub-Location boundary problems ..................... 89 4.5 Conclusion . ........................................ 91 5. Chapter 5 The census geographical coding methodology ........................................ 9 6 5.1 Introduction . 9 6 5.2 The census areal units ............................. 97 3 5.3 The code scheme . ................................... 99 5.3.1 The province and District codes .................... 101 5.3.3 Location codes . ................................... 105 5.3.4 Sub-Location codes ................................. 106 5.3.5 EA codes . • • . 10 7 5.4 Conclusion ......................................... 109 6. Chapter 6 Monitoring the census maps and documents .......................................... 110 6.1 Introduction ................. o o o o • o •••••••••••••••• 110 6.2 The need for a filing and indexing system .......... 111 6.3 Indexing and filing the census maps and documents .. 113 6.4 Thetopographicmaps ............................... 114 6.5 TheSub-Locationfiles .....•....................... 118 6.6 The drafted enumeration area maps .................. 121 6.7. Conclusion . ........................................ 123 7. Chapter 7 - Preparation and reproduction of census enumerationareamaps .•............................ 125 7.1 Introduction . ...................................... 12 5 7.2 Map specifications and general layout .............. 126 7.3 EAmapcompilation ................................. 131 7.4.1 Determining the scale of each EA map ............... 136 7.4.2 Tracing Sub-Location outlines .....••......•....... 137 7.4.3 Enlarging Sub-Location outlines to the required scale .. .................................. 138 7.4.4 Plotting extra information on the map compilation . ...................................... 139 7.4.5 Checking and verification of map compilation ....... 140 4 7. 5 Fair drafting of EA maps ••••••••...••••.•........•. 140 7 • 6 Map reproduction ••••••••••••• o o o • o o o o o • o o o • o o o o o o •• 14 2 7 o 7 Conclusion. o o o o o o o o o o o o o o o o o o o o o o o o o o o . o .•.••.•...• 145 8. Chapter 8 - Digitising the 1989 population census geographical base .................................. 149 8o1 Introduction . ..................................... 149 8o2 System and Equipment o o o o o o o o o o o o o o o •• o o • o o o •• o o o o • o150 8.2 Map sources . ....................................... 151 8.3 Preparing the maps for digitising. o ... o •.......... o155 8o4 Data capture ........................................ 158 8o4o2 Digi tising the coverage features o o o o o o . o ......... o . 160 8o4o3 Errors detected during digitising •• o .•... o •... o o ••. 160 8o4o4 Coverage topology and attribute tables o .• o o • o • o •.. o162 8o5 Editing the coverage features o • o o o ••••• o o ••.• o •• o . o 170 8o5o1 Selecting a coverage to edit. o o o o o o o o • o • o • o • o •. o o •• 17 2 8o5o2 Drawingcoveragefeatures •••••••••• o.oooo•••ooooo•o173 8.5o3 Adding arcs and label points o o o o o o o o o ••• o o o ••••• o •• 17 4 8o5.5 Removingpseudonodesooooooooooooooooo•o•o•oo••••oo175 8o5o6 Snappingnodestogetherooooooooooooooooooo••••ooooo175 8o5o7