Biological data: georeferencing

Monica Papeş

University of Kansaspmonica@ku.edu

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Potential issues with NHM occurrence data• Taxonomy: unidentified or wrong identifications; outdated taxonomy • Sample bias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