Georeferencing:Collaboration and Automation

John Wieczorek1

Reed Beaman2

1Museum of Vertebrate ZoologyUniversity of California, Berkeley

2Center for Biodiversity ResearchUniversity of Kansas

Caveat:I’m going to over-simplify

everything.

Warning:Apertem os Cintos

Fasten your seat belts

What is georeferencing?

Georeferencing is the expression of a

terrestrial spatial description in

coordinates within a

frame of reference

Terrestrial Spatial Descriptions:

• Bakersfield• 10 mi E (by air) Bakersfield• 5 mi from Bakersfield• 2 mi E and 1.5 mi N of Bakersfield• 13 mi E (by road) Bakersfield• 10.2 mi E of Bakersfield• E of Bakersfield T29S R29E

Sec.34

Coordinates

• Points (have no spatial footprint)

• Shapes (have bounded footprint)

Polygons

Multipolygons

Coordinate Systems

• decimal degrees35.3733 -119.0178

• degrees minutes seconds35 22 23.88 N, 119 1 4.08 W

• degrees, decimal minutes 35 22.398 N, 119 1.068 W

• UTM Zone 11S 316695E 3916111N

• Innumerable other grid-based systems

Frames of Reference

• Australian Geodetic 1984

• Japanese Geodetic Datum 2000

• North American Datum 1983

• South American 1969

• World Geodetic System 1984

Geodetic Datums

• … over 100 others

Why is the datum important?

What is an ideal georeference?

I propose that it is a shape, with a frame of reference, which exactly describes the spatial extent of a terrestrial location.

The answer depends on the questions you want to address.

“The Shape Method”

“Davis, Yolo County, California”

“Davis, Yolo County, California”

Is this method currently practical?

• Requires sophisticated software to capture these data.

• Requires database capabilities beyond the scope of many collections

• Requires baseline digital data that are neither freely, nor globally available.

The remedy is costly.

What is practical?

Describe spatial extent using elements that can be captured and stored by anyone using current technology.

One possible solution

Describe the locality using one set of coordinates, the datum, and a bounding radius.

“The Point-Radius Method”

“Davis, Yolo County, California”

“Davis, Yolo County, California”

Coordinates: 35.32443 -119.32343Horizontal Geodetic Datum: NAD27Maximum Error Distance: 8325 m

Advantages

This remedy is relatively inexpensive.

• Describes the locality in a minimal element set.

• Obviates the need for investment in new technology.

• Establishes a maximum spatial scale of the locality.

• Does enable spatial visualization and a broad range of analytical applications

Disadvantages

The remedy will remain just as costly as before.

• This solution does not contribute toward the ideal solution.

• There may be future applications for spatial footprints that cannot be met by the data produced by the Point-Radius Method.

Who is georeferencing?

Who isn’t, and why not?

Who is georeferencing?

• MaNIS – 17 mammal collections; institutions in Canada, Mexico and the United States; global holdings; 1.4M specimens; 284k localities; 3 years; started Sep 2001.

http://elib.cs.berkeley.edu/manis

• HerpNet – 37 North American herpetological collections; global holdings; ca. 3M specimens; 5 years; first georeferencing North and Central American localities; starts 2003.

How are we georeferencing?

How are we georeferencing?

Collaboration

http://elib.cs.berkeley.edu/manis/search.shtml

Advantages

• Reduces overall cost of supplies – no duplication• Expands the pool of resources – geographic

expertise and reference material• Increases georeferencing rates – economy of

scale• Promotes standardization – methods• Increases skills in a community• Increases exposure and awareness inside and

outside of a community

Disadvantages

• Vulnerable to procrastinators, cheaters, and numbskulls.

• Can distance georeferencing process from useful primary resources (e.g., field notes).

• Introduces time sensitivity to the georeferencing process

• Requires project-level management

One way to improve upon the georeferencing process will be

to collaborate with a distributed query mechanism

already in place.

Reed will talk about another way we hope to improve the

georeferencing process.

Special Thanks

CONABIOBell Museum

Kansas State UniversitySan Diego Natural History

MuseumA. Townsend Peterson1

1University of Kansas Natural History Museum