john wieczorek museum of vertebrate zoology university of california, berkeley georeferencing...

John WieczorekMuseum of Vertebrate Zoology

University of California, Berkeley

Georeferencing Introduction: Collaboration to Automation

Georeferencing

Collaborations

Automation

Georeferencing

Collaborations

Automation

What is a georeference?

A numerical description of a place that can be mapped.

What is a georeference?

A numerical description of a place that can be mapped.

What is a georeference?

In other words…

ID Species Locality1 Lynx rufus Dawson Rd. N Whitehorse2 Pudu puda cerca de Valdivia3 Canis lupus 20 mi NW Duluth

9 Ursus arctos Bear Flat, Haines Junction

4 Felis concolor Pichi Trafúl5 Lama alpaca near Cuzco6 Panthera leo San Diego Zoo7 Sorex lyelli Lyell Canyon, Yosemite8 Orcinus orca 1 mi W San Juan Island

What we have:Localities we can read

Darwin Core Location Terms

–higherGeography–waterbody, island, islandGroup–continent, country, countryCode, stateProvince, county, municipality

– locality–minimumElevationInMeters, maximumElevationInMeters, minimumDepthInMeters, maximumDepthInMeters

What we want:Localities we can map

Darwin Core Georeference Terms

– decimalLatitude, decimalLongitude– geodeticDatum– coordinateUncertaintyInMeters– coordinatePrecision– pointRadiusSpatialFit– footprintWKT, footprintSRS,

footprintSpatialFit– georeferencedBy, georeferenceProtocol– georeferenceSources – georeferenceVerificationStatus– georeferenceRemarks

What is a georeference?

A numerical description of a place that can be mapped.

“Davis, Yolo County, California”

“point method”

Coordinates: 38.5463 -121.7425Horizontal Geodetic Datum: NAD27

Data Quality

• data have the potential to be used in ways unforeseen when collected.

• the value of the data is directly related to the fitness for a variety of uses.

• “as data become more accessible many more uses become apparent.” – Chapman 2005

• the MaNIS/HerpNET/ORNIS guidelines follow best practices (Chapman and Wieczorek 2006) to enhance data quality and value

What is an acceptable georeference?

A numerical description of a place that can be mapped

and that describes the spatial extent of a locality

and its associated uncertainties.

“Davis, Yolo County, California”

“bounding-box method”

Coordinates: 38.5486 -121.754238.545 -121.7394

Horizontal Geodetic Datum: NAD27

“Davis, Yolo County, California”

“point-radius method”

Coordinates: 38.5468 -121.7469Horizontal Geodetic Datum: NAD27Maximum Uncertainty: 8325 m

What is an ideal georeference?

A numerical description of a place that can be mapped

and that describes the spatial extent of a locality

and its associated uncertaintiesas well as possible.

“Davis, Yolo County, California”

“shape method”

“20 mi E Hayfork, California”

“probability method”

point easy to produce no data quality

bounding-box simple spatial queriesdifficult quality assessment

point-radius easy quality assessmentdifficult spatial queries

shape accurate representationcomplex, uniform

Method Comparison

probability accurate representationcomplex, non-uniform

MaNIS/HerpNET/ORNIS (MHO) Guidelines

http://manisnet.org/GeorefGuide.html

• uses point-radius representation of georeferences

• circle encompasses all sources of uncertainty about the location

• methodology formalizes assumptions, algorithms, and documentation standards that promote reproducible results

• methods are universally applicable

Darwin Core Georeference Terms

– decimalLatitude, decimalLongitude– geodeticDatum– coordinateUncertaintyInMeters– coordinatePrecision– pointRadiusSpatialFit– footprintWKT, footprintSRS,

footprintSpatialFit– georeferencedBy, georeferenceProtocol– georeferenceSources – georeferenceVerificationStatus– georeferenceRemarks

Georeferencing

Collaborations

Automation

Collaborative DistributedDatabases for Vertebrates

Collaborations

MaNIS Localities Georeferenced

n = 326k localities (1.4M specimens)r = 14 localities/hr (point-radius method)

t = 3 yrs (~40 georeferencers)

ORNIS Localities Georeferenced

n = 267k localities (1.4M specimens)r = 30 localities/hr (point-radius method)

t = 2 yrs (~30 georeferencers)

Scope of the Problem for Natural History Collections

~2.5 Giga-records

Scope of the Problem for Natural History Collections

~2.5 Giga-records

~6 records per locality*

~14 localities per hour*

* based on the MaNIS Project

Scope of the Problem for Natural History Collections

~2.5 Giga-records

~6 records per locality*

~14 localities per hour*

~15,500 years

* based on the MaNIS Project

Scope of the Problem for Natural History Collections

~2.5 Giga-records

~6 records per locality*

~14 (30) localities per hour*

~15,500 (7233) years

* based on the MaNIS (ORNIS) Project

Georeferencing

Collaborations

Automation

http://www.biogeomancer.org

Automation

Combining the Best in Georeferencing

GeoLocate

DIVA-GIS

MaNIS Georeferencing Calculator

BioGeomancer Classic

• Geodetic Datum:defines the position of the origin, scale, shape, and orientation of a 3-dimensional model of the earth. Example: WGS84.

• Coordinate System: defines the “units of measure” of position with respect to the datum. Example: latitude, longitude in degrees, minutes, seconds

Geographical Concepts:

Map Projections:• mathematical

transformations of the 3-D model of the surface of the earth onto a 2-D map.

• there are many (e.g., conical, cylindrical, azimuthal) - they all suffer from distortions (area, shape, distance, or direction), but some preserve areas or distances.

• When measuring distances on paper maps, use an equal distance projection, if available, otherwise understand the implications.

Named place: a place of reference in a locality description. Example: “Davis” in “5 mi N of Davis”

Areal extent: the geographic area covered by a named place (feature). Example: the area inside the boundaries of a town.

Linear extent: the distance from the geographic center to the furthest point of the areal extent of a named place.

Georeferencing Concepts

• Offset: the distance from a named place. Example: “5 mi” in “5 mi NE of Beatty”.

• Heading: the direction from a named place. Example: “NE” in “5 mi NE of Beatty”.

Georeferencing Concepts

• coordinateUncertaintyInMeters:“The horizontal distance (in meters) from the given decimalLatitude and decimalLongitude describing the smallest circle containing the whole of the Location. Leave the value empty if the uncertainty is unknown, cannot be estimated, or is not applicable (because there are no coordinates). Zero is not a valid value for this term.” (from Darwin Core)

• Maximum Error Distance: same as coordinateUncertaintyInMeters, except the units are the same is in the locality description, not necessarily meters.

Georeferencing Concepts

Sources of uncertainty:

Coordinate Uncertainty

Map scale

The extent of the locality

GPS accuracy

Unknown datum

Imprecision in direction measurements

Imprecision in distance measurements (1km vs. 1.1 km)

20° 30’ N 112° 36’ WScale Uncertainty (ft) Uncertainty (m)

1:1,200 3.3 ft 1.0 m

1:2,400 6.7 ft 2.0 m

1:4,800 13.3 ft  4.1 m

1:10,000 27.8 ft 8.5 m

1:12,000 33.3 ft 10.2 m

1:24,000 40.0 ft  12.2 m

1:25,000 41.8 ft 12.8 m

1:63,360 106 ft 32.2 m

 1:100,000 167 ft 50.9 m

1:250,000 417 ft 127 m

Georeferencing Calculator Example

Locality:0.5 km N of Little mermaid, Copenhagen,

DK

Start with original coordinates for the mermaid:

55° 41' 34.18" N 12° 35' 56.73" E

Then use the Georeferencing Error Calculator to determine the final coordinates AND the uncertainty.

Georeferencing Error Calculator:0.5 km N of Little mermaid, Copenhagen, DK

55° 41' 34.18" N 12° 35' 56.73" E

Capture georeferences in database or spreadsheet (we will use an Excel template for examples)

Georeferencing Templates