Online resources for georeferencing
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Online resources for georeferencing

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Online resources for georeferencing

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Google Maps


  • Search & directions

    • Free text search, zoom -dependent

    • Directions for travelling by car, bike, public transport and foot

    • Data compiled from different sources

  • Maps

    • Datum: WGS84

    • Views: map, satellite (= aerial photography), terrain, Google Street View + various layers of information

    • Data compiled from different sources (indicated at the bottom of each map)

  • Third Party Plug-ins extend functionality

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Google Maps - Searching

Search now with suggestions

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Google Maps - Viewing



Terrain (under ‘More’)

Earth (plug-in required)

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Google Maps – Street View

I collected here

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Google Maps – Getting coordinates

  • Requires additional widgets or plug-ins

    • Activate LatLng Marker in Google Maps Labs

    • Install a mapplet like GPS Location or Position Finder in ‘My Maps > Browse the directory’. Now deprecated!

    • Use Canadensys LatLong Crosshairs bookmarklet:

  • Use Distance Measurement Tool to measure extent

  • Use My Maps to save markers, create maps, share with others (including kml import)

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Google Maps – Getting coordinates

Google Maps Labs

LatLng Marker

Right-click and‘Drop LatLng Marker’

(activate in ‘Labs’ first)

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Google Maps – Getting coordinates

Canadensys bookmarklet

Click to toggle


Pan map to change position

Click to get coordinates

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Google Maps – Measuring extent

Distance Measurement Tool

(activate in ‘Labs’ first)

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Google Earth


  • 3D globe desktop application

  • Same data as Google Maps

    • Datum: WGS84

    • No Map or Terrain view

  • Similar functionalities as Google Maps

    • Search more limited than Google Maps (no suggestions)

    • Right-click and choose ‘Get Info’ for coordinates

    • Use ruler to measure extent

    • Several coordinate formats

    • Numerous information layers (format: kml)

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  • Google Maps interface

    • Datum: WGS84 (& NAD27)

    • Map, satellite, hybrid and terrain

    • Topo, DOQ, NEXRAD and Mapnik

    • Free text search not Zoom level-dependent

    • Markers cannot be moved, but new markers can be placed at crosshairs (click ‘Mark’)

    • Several coordinate formats for each marker + heading and distance from crosshairs

    • Saves all markers automatically

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  • Worldwide gazetteer for citiesand towns

  • Google Map basemaps

  • Great for hard to find localities, especially outside US

    • Datum: WGS84

    • Search with country or worldwide

    • Provides DMS, DD, UTM coordinates

    • Includes contours (but spotty coverage)

  • Example: Qandahar or Kandahar, AF

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GEOnet Names Server (GNS)


  • Worldwide data from NGA andUS BGN

    • NIMA = National Imagery andMapping Agency

    • Datum: WGS84

    • Degrees minutes seconds,precision to nearest minute

    • Feature type

    • Used as a source for many gazetteers

  • For US data, use Geographic Names Information System (GNIS):

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Geographical Name Search Service (GNSS)


  • Canadian data by the CanadianGeographical Names Service(CGNS)

    • Datum: NAD83

    • Degrees minutes seconds anddecimal degrees

    • Feature type

  • Full Canadian Geographical Names datasets can be downloaded from GeoBase:

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Falling Rain


  • Worldwide gazetteer for citiesand towns

  • Great for hard to find localities,especially outside US

    • Datum: WGS84

    • Degrees minutes (seconds), based on NIMA

    • Browse to find locality (no search)

    • Provides hierarchy, alternative names, topo maps, altitude, weather information and location of nearby towns in nautical miles (nm). Tip: Use Google/Chromey to translate nm into km.

  • Example: Qaryeh-ye Gol`alam, Velayat-e Lowgar, AF

  • You can also check against Statoids:

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Getty Thesaurus of Geographic Names (TGN)


  • Worldwide gazetteer byThe Getty

  • Useful for finding alternativeand old names

    • Feature types

    • Geographical hierarchy

    • Coordinates only to minutes (or not at all)! Use recent name and search in Google Maps

  • Example: Big Apple, inhabited place, United States

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FuzzyG – JRC Fuzzy Gazetteer


  • Worldwide gazetteer designed for bad spelling!

  • Useful for finding alternative, doubtful spelling,old names

    • Feature types

    • By continent

    • Coordinates only to minutes (or not at all)! Use recent name and search in Google Maps

  • Example: Narobi, Africa

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  • UTM = Universal Transverse Mercator

    • Divides earth in 60 UTM zones = 6 degrees per zone

    • Datum: WGS84 and others

    • Notation: Zone Easting Northing = 17N 630084 4833438

    • Zone includes hemisphere (17N) or latitude band (17T): MGRS

    • Default extent: 30m (if recorded with GPS receiver)


    • UTM Calculator:

  • MTM = Modified Tranverse Mercator

    • Used in Canada: zones are 3 degrees, different codes, false easting and scale, etc.

    • UTM/MTM Calculator:

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UTM – 17T 630084 4833438 (CN Tower in Toronto)

Equator = 0m northing

4833438m northof equator

Equator = 10,000,000m

false northing for

Southern Hemisphere

Central meridian= 500,000mfalse easting

130084m east ofcentral meridian

Georeferencing workshop - Online resources - 2010.06.05


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Public Land Survey System (PLSS)

  • Mainly used in the US West, Midwest and some Southern states in early surveys

  • System of Township-Range-Section (TRS):T13N-R14E-S15, Arizona, Coconino County

  • Graphical Locator:

    • Translates TRS in decimal degrees

    • Datum: NAD27

  • Determine state and meridian (BLM):

  • For extents:

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Other Resources

  • GPS Visualizer:

    • Use to translate a file with coordinates into kml or a picture

    • Similar: for publications

  • GeoLocate:

    • Georeferencing desktop and web application

    • Useful for roads and rivers (US only)

  • Statoids:

    • Information about administrative divisions (provinces, counties) and their history, area, population, codes, etc.

    • No coordinates!

    • Similar: CIA World Factbook

  • See for more…