Georeferencing

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*Note the contents of this wiki are under active revision and may change often.*

Georeferencing

As applied to natural history collections data, georeferencing is the process of determining geographic coordinates (typically latitude and longitude) from a textually described locality description. Measurements of uncertainty associated in the form of a radius from the determined point or a polygon encompassing the maximum possible extent of a locality description are usually included in the georeferencing process.


Geographic Concepts Related to Georeferencing

It is not uncommon for georeferencing to involve numerous resources from various sources using differing scale and geographic systems. Ensuring an accurate and reliable result in georeferencing requires a basic understanding of the following concepts.

Geodetic datum

A model of the earth used for geodetic calculations. A geodetic datum describes the size, shape, origin, and orientation of a coordinate system for mapping the surface of the earth.
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Coordinate System

A system used to denote direct or relative positions by coordinates; Examples of two-dimensional coordinate systems are Latitude/Longitude and Universal Transverse Mercator (UTM)
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Geographic Coordinate System

The net or graticule of lines of latitude (parallels) numbered 0° to 90° north and south of the equator, and lines of longitude (meridians) numbered 0° to180° east and west of the international zero meridian of Greenwich, used to define locations on the Earth's surface (disregarding elevation) with the aid of angular measure (degrees, minutes and seconds of arc).
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Projection

A projection is a representation of the earth's three-dimensional surface as a flat two-dimensional surface. This normally involves a mathematical model (of which there are many) that transforms the locations of features on the earth's surface to locations on a two- dimensional surface. Such representations distort one or more parameters of the earth's surface such as distance, area, shape, or direction.
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Georeference Practices

Click here for a ‘Guide to Best Practices for Georeferencing” - Chapman, A.D. and J. Wieczorek (eds). 2006


Specialized Georeferencing Tools

BioGeomancer Log.png

The BioGeomancer Project is a worldwide collaboration of natural history and geospatial data experts. The primary goal of the project is to maximize the quality and quantity of biodiversity data that can be mapped in support of scientific research, planning, conservation, and management. The project promotes discussion, manages geospatial data and data standards, and develops software tools in support of this mission.
To learn more about the BioGeomancer workbench click here (Warning some portions of this site are down, including the Workbench)

GeoLocate Logo.png

The GEOLocate project is an effort to develop software and services for translating textual locality descriptions associated with biodiversity collections data into geographic coordinates. In addition to the automated processing of locality description, one of the goals of was to provide an interface by which users could georeference records one by one or in batches from files, visualize and correct calculated coordinates and determine polygonal error descriptions.
In addition to manual and batch methods, GEOLocate also now includes a Collaborative Georeferencing client, a mechanism whereby groups of users can form communities to collaboratively georeference and verify a shared dataset. Verification and correction of the computer generated geographic coordinates is accomplished using the GEOLocate desktop and/or web application. GEOLocate allows users to login to their communities, retrieve and visualize results, make any necessary corrections, provide additional comments, define errors as polygons, and save the results back to the shared dataset. The verified results of georeferencing can then be downloaded via the portal’s data management interface for
re-import to the parent database.
Click here for further information

Georeferencing Calculator

The Georeferencing Calculator is a java applet created as a tool to aid in the georeferencing of descriptive localities such as those found in museum-based natural history collections. It was specifically designed for the Mammal Networked Information System (MaNIS) Project and has been adopted as well by HerpNet and ORNIS. The application makes calculations using the methods described in the Georeferencing Guidelines


Natural History Databases with Integrated Georeferencing Capabilities

Arctos

Specify

Symbiota


Selected Online Resources & Tools

*A more inclusive list can be found at herpnet*

Google Earth


MaNIS/HerpNet/ORNIS Georeferencing Guidelines


Georeferencing for Dummies

This document is a list of locality types based on Georeferencing guidelines (Chapman, A.D. and J. Wieczorek (eds). 2006), as well as providing what is considered the best for georeferencing and finding the extent and error for each type of locality.

Statoids

Provides geographic and administrative divisions, in addition to historical information related to many countries.


FAQ

Workshops

The First iDigBio GWG Train the Trainers Workshop: Expanding the Biodiversity Natural History Collections Georeferencing Community October 8 - 12, 2012


The Second iDigBio GWG Train the Trainers Workshop: Expanding the Biodiversity Natural History Collections Georeferencing Community Date TBD, 2013


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