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Georeferencing of RMCA data

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

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Georeferencing of RMCA data

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

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

  3. RMCA data for HerpNET • RMCA will contribute its entire registered amphibian collection (ca. 200,000 specimens) to GBIF and HerpNET • ca. 3000 unique localities • mainly from DRC, Burundi, Cameroon, Ivory Coast and Togo • stored in DataPerfect • specimen records, linked with locality names (stations) (collector’s coordinates)

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

  5. GIS processing • use of GIS for georeferencing localities and calculation of extent and error

  6. GIS processingStep 1: Resources • maps of DRC, Burundi, Rwanda (mostly 1:200,000) • scanned at 300 dpi • detailed recording of map properties: • scale • projection • datum

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

  8. Visualization of localitiesExample

  9. GIS processingStep 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

  10. GIS processingStep 4: Object digitization • digitization of necessary objects according to case: • case code • station (locality) ID

  11. GIS processing – object digitizationExample

  12. GIS processingStep 5: Extent and error calculation • digitized objects  coordinates & extent • map specifications  error • programming of algorithms & output table  point and radius

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

  14. Example extent calculation (1)Named place (II)

  15. Example extent calculation (2)Voronoi approach (I)

  16. Voronoi approach

  17. GIS processingStep 6: Connection specimen records • connecting locality ID (with point and radius) with specimen data • export in desired format

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

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

  20. 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

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