Projection

Projections and Datum Transformations

Brief introduction to projections and spatial transformations in GRASS

A GRASS location is referenced with a single projection and coordinate system (or unreferenced as XY location). When creating a new location from an existing raster or vector map using the tools available from the startup screen or the map import commands, projection and coordinate system are defined. To change the projection of maps, a new location has to be created and the desired maps have to be reprojected into it from the source location as explained below.

Read on in projectionintro...

Creation of a GRASS location

• for the concept, see Location and Mapsets
• for creating a location, see GRASS Location Wizard
• Reprojection, see Map Reprojection

Support Material

• Vector data: have enough vertices in your vector data:

  

  Results in EU LAEA (EPSG: 3035)

• Ready to use .PRJ files (in the usual WKT format) as used by recent versions of ESRI ArcView: download

See also

View Map Projections

• http://map-projections.net/singleview.php
• Cartographical Map Projections by Carlos A. Furuti

Lists

• EPSG Dataset
• ASPRS Grids and Datum
• Projections Transform List (PROJ4)
• MapRef - The Collection of Map Projections and Reference Systems for Europe
• Information and Service System for European Coordinate Reference Systems - CRS

Related to Germany:

• http://support.esri-germany.de/files/support/KoordinatensystemeInDeutschland.pdf
• http://support.esri-germany.de/files/support/KoordinatensystemeNachbarnDeutschlands.pdf
• http://support.esri-germany.de/files/support/KoordinatensystemeWeltweit.pdf

Related to Austria:

• Projection parameters of Austria

Google Map Projection

Also called "pseudo-mercator" - note that there are many issues with this projection! Handle with care.

• http://www.sharpgis.net/2007/07/27/TheMicrosoftLiveMapsAndGoogleMapsProjection.aspx
• http://cfis.savagexi.com/articles/2006/05/03/google-maps-deconstructed