biological data: georeferencing monica papeş university of kansas [email protected]
TRANSCRIPT
Sources of occurrence data
• Natural history museum collections (many in distributed databases) – contains the bulk of species’ distribution information
• Literature citations (monographs, papers, etc)
• Surveys
Potential issues with NHM occurrence data• Taxonomy: unidentified or wrong identifications; outdated taxonomy • Sample bias
• Locality description too vague, misspelled, unreadable handwriting, etc.
• Faulty georeferencing
What is georeferencing?(simple response)
• Assigning geographic coordinates to a locality description
USA, Georgia, Augusta, Wheeless Rd., 0.5 mi S of Gordon Hwy
locality georeferenced to Latitude: 33.444642 Longitude:-82.045296
Where to find coordinates?
1. Gazetteers
- Paper based
- Online databases
Where to find coordinates of localities?
1. Gazetteers
- Paper based
- Online databases
GeoNet Names Server – worldwide coverage, no maps
http://gnswww.nga.mil/geonames/GNS/index.jsp
GeoNet Names Server – worldwide coverage, no maps
http://gnswww.nga.mil/geonames/GNS/index.jsp
Another example of online databases:
Alexandria Digital Library – worldwide coverage, with maps
http://middleware.alexandria.ucsb.edu/client/gaz/adl/index.jsp
Where to find coordinates of localities1. Gazetteers
- Paper based
- Online databases
2. Maps
- Paper based
- Electronic (digitized)
*Exhaustive list of sources can be found on HerpNet website:
http://www.herpnet.org/Gazetteer/GeorefResources.htm
Georeferencing… more in depth look
• e.g.1: Lawrence
• e.g.2: Lawrence, Douglas Co, Kansas, USA
• e.g.3: 5 km E of Lawrence, DG, KS, USA
• e.g.4: 5 km SE of Lawrence, DG, KS, USA
• …
More in depth look… issues
• Assumptions: localities are accurate and complete
• Locality string has to be interpreted
e.g. USA, KS, Dickinson Co, Jct I-70 & KS Hwy 15 in Abilene, 1 mi S, 3.5 mi W
• There are inherent uncertainties with each locality description
(even with GPS coordinates!)
Causes of uncertainty:
•The extent of the locality – can be estimated using:The extent of the locality – can be estimated using:
→ →bounding box methodbounding box method
→ →point-radius methodpoint-radius method
-... in future: shape method: complex, -... in future: shape method: complex,
complete representationcomplete representation
• Imprecision in distance or direction measurements; Imprecision in distance or direction measurements; map scale; unknown datum; GPS accuracymap scale; unknown datum; GPS accuracy
Thus… we need to calculate a “confidence interval” for
georeferencing done. Luckily, there is a CALCULATOR for this
purpose! http://manisnet.org/gci2.html
Automated, batch processing tools
(The future looks bright!)
GEOLocate – georeferencing without error estimatesdesigned for North America; recently expanded to include the whole world
• http://www.museum.tulane.edu/geolocate/default.aspx
BioGeomancer – georeferencing with error estimatesStill in the developing stage, but improving fast
• http://www.biogeomancer.org/
Everything there is to know about georeferencing:
Guide to Best Practices for GeoreferencingEdited by Arthur D. Chapman and John Wieczorek (2006)
Available for download:
http://www.gbif.org/prog/digit/Georeferencing
Very bad localities…. REAL LOCALITIES FROM MaNIS project
T-shirt: http://herpnet.org/gbif/tshirt.html
Requires specific knowledgeNon-sensical
Biologically unlikelyVague