Abstract:
The Eastern African Coastal and Marine Environment Resource Database is a comprehensive 1:250,000-scale vector database of the Kenya Coastal Zone. It consists of geographic, attribute, and textual data which can be accessed, queried, displayed, and modified. The database was developed under the Eastern African Action Plan, with the collaboration of UNEP/GRID-PAC, UNEP/OCA-PAC, and KEMFRI. The ... primary sources of data are the Survey of Kenya 1:250,000 series, National Museums of Kenya, Kenya Ports Authority, Coastal Development Authority, Kenya Wildlife Service, and Kenya Government Departments: Fisheries, Agriculture, Meteorology, Mines and Geology.
Data Sources The primary sources of data are the Survey of Kenya 1:250,000 series, Landsat Thematic Mapper images, and socio-economic data from various Government ministries, departments, and institutes.
Naming Conventions A naming convention was established to allow users to identify the contents of layers based on their name. Coverage names begin with a two letter abbreviation representing the country code (for example, KE:-Kenya) followed by a descriptive term representing the theme. The country code being two characters in length plus the descriptive term, which is usually six characters long, conforms to the Direct Operating System (DOS) naming convention. An example of this would be as follows:- the elevation coverage would be called KEELEVAT, the KE representing the abbreviation for Kenya and the ELEVAT representing elevation. A full list of country codes for the East African region is as follows:-
List by country name Country Name Data Code Comoros CN Kenya KE Madagascar MA Mauritius MP Mozambique MZ Reunion RE Seychelles SE Somalia SO Tanzania TZ
Edgematching Edgematching was done manually working from the top most map sheet (Kolbio: SA-37-8) to the bottom most (Mombasa: SB-37-3). In this way any errors would be distributed in a systematic way. The greatest errors are in the order of 750 meters on the ground which is 3 millimeters on the map. These errors occurred between the following map sheets:- Voi (SA-37-14) / Kilifi (SA-37-15)and Voi (SA-37-14) / Lushoto (SB-37-2).
Annotation All feature names which include points, lines or polygons have an entry in the attribute table describing the feature. Additional attributes may also exist for the particular feature, however this varies from feature to feature.
General production process Coverages developed for the database were derived from three sources: 1:250,000 scale paper maps prepared by the Survey of Kenya, Landsat Thematic Mapper Data, and socio-economic data from the Kenya Marine Fisheries Institute (KMFI), the Kenya Wildlife Service (KWS) and other Government Ministries and NGO's.
1:250,000 paper maps Twelve TIC's (control points) were selected from the map sheet, based on the latitude/longitude grid on the sheet. The reason for this is that one of the other sheets only has a latitude/longitude grid where as the others have both a latitude/longitude grid as well as a UTM grid. In this way, consistency is being maintained between all the map sheets covering the Kenya coastal zone.
Arc/info conversion MACRO PROGRAMME was used to convert a standard ASCII text file of Latitude/Longitude coordinates into Universal Transverse Mercator coordinates.
SML TO PROJECT DECIMAL DEGREES FILE INTO UTM ZONE 37 INPUT PROJECTION GEOGRAPHIC SET INPUT UNITS AS DECIMAL DEGREES UNITS DD SPHEROID CLARKE1880 PARAMETERS OUTPUT PROJECTION UTM UNITS METERS YSHIFT 10000000 PARAMETERS 39 00 00 00 00 00 END [ARC] Createcov ***tic {ARC} Tables > Select ***tic.tic > Add > TICID = ? > XTIC = ? > YTIC = ? This is done for all 12 UTM Tic Ids and coordinates. >List This is done to check that the Tic Ids and coordinates are correct. > Q stop A tile boundary was then added to the coverage to help in the digitization of the map sheet. This coverage <***tic> was then used in the creation of all the other coverage layers that were digitized from the map sheet.
1:250,000 paper maps were used due to lack of stable mylar or acetate copies. All features:- points, lines, and polygons were digitized using PC Arc/Info 3.4D Plus software running on a Gateway 2000 P5-90 PC and a CalComp 9100 digitizing board. Editing was carried out to eliminate obvious errors, after which the data was plotted at scale using a Hewlett Packard Design Jet 650 C inkjet plotter and then compared to the source for positional accuracy, completeness, and topological correctness. All of the data layers were checked using this method and all edits were verified.
Line and Point attribute codes were assigned interactively at the time of initial data capture. Polygon attributes were assign after topology had been reached. Editing was carried out to eliminate obvious errors, after which the data was plotted at scale and then compared to the source correctness. All of the data layers were checked using this method and all edits were verified.
All the data was finally plotted at scale in a single composite and attribute code value validity, attribute code consistency, topology errors, attribute field definition correctness, and internal data structure correctness were checked. In addition Arc/View 2.1 was used to carry out a quick visual check on the data.
Landsat Thematic Mapper Data Two full scenes and one quad were used in the land cover classification, more details concerning the methodology used in the classification can be found in Annex 3.
Line and Point attribute codes were assigned interactively at the time of initial data capture. Polygon attributes were assigned after topology had been reached. Editing was carried out to eliminate obvious errors, after which the data was plotted at scale and then compared to the source correctness. All of the data layers were checked using this method and all edits were verified.
All the data was finally plotted at scale in a single composite and attribute code value validity, attribute code consistency, topology errors, attribute field definition correctness, and internal data structure correctness were checked. In addition Arc/View 2.1 was used to carry out a quick visual check on the data.
Socio-economic Data These data came in various forms (from digital data to reports), which were then converted into
Line and Point attribute codes were assigned interactively at the time of initial data capture. Polygon attributes were assigned after topology had been reached. Editing was carried out to eliminate obvious errors, after which the data was plotted at scale and then compared to the source correctness. All of the data layers were checked using this method and all edits were verified.
All the data was finally plotted at scale in a single composite and attribute code value validity, attribute code consistency, topology errors, attribute field definition correctness, and internal data structure correctness were checked. In addition Arc/View 2.1 was used to carry out a quick visual check on the data.
