Georeferencing of RMCA data An Tombeur HerpNET workshop Royal Museum for Central Africa December 2006

Overview RMCA data GIS processing – Resources for georeferencing – Visualization of localities – Case identification – Object digitization – Error and extent calculation – Connection with specimens Conclusion

RMCA data for HerpNET RMCA will contribute its entire registered amphibian collection (ca. 200,000 specimens) to GBIF and HerpNET ca unique localities mainly from DRC, Burundi, Cameroon, Ivory Coast and Togo stored in DataPerfect specimen records, linked with locality names (stations) (collector’s coordinates)

RMCA data: processing exported to spreadsheet georeferencing according to HerpNET protocol: – checking of coordinates – addition of radius (maximum error distance)

GIS processing use of GIS for georeferencing localities and calculation of extent and error

GIS processing Step 1: Resources maps of DRC, Burundi, Rwanda (mostly 1:200,000) scanned at 300 dpi detailed recording of map properties: – scale – projection – datum

GIS processing Step 2: Visualization of localities Georeferencing of the maps (ca. 5 reference points) with GIS Use map as background layer Plotting of the (working) localities

Visualization of localities Example

GIS processing Step 3: Case identification HerpNET locality types: – urban area – remote named place – near a named place – river –...  different calculation of extent & error each locality: identification of case

GIS processing Step 4: Object digitization digitization of necessary objects according to case: – case code – station (locality) ID

GIS processing – object digitization Example

GIS processing Step 5: Extent and error calculation digitized objects  coordinates & extent map specifications  error programming of algorithms & output table  point and radius

Example extent calculation (1) Named place (I) Named place on map  different types  different calculation of extent

Example extent calculation (1) Named place (II)

Example extent calculation (2) Voronoi approach (I)

Voronoi approach

GIS processing Step 6: Connection specimen records connecting locality ID (with point and radius) with specimen data export in desired format

Used software georeferencing of maps, digitizing of objects: MapInfo Pro 7.8 programming error calculation: MapBasic 4 compatible with: – QGIS – PostGIS

Conclusion Advantages of GIS processing: – alternative extent & error calculations possible – more precise – in term: faster – easy correction of errors – geographic analysis

Thanks to: Funding: HerpNET/MVZ Promotor (RMCA): Danny Meirte Co-promotor (RMCA): Patricia Mergen Technical support: – MVZ: Carol Spencer, Aaron Steele – RMCA: Garin Cael, Bart Meganck, Frank Theeten