Then we do a second reprojection with new automated vertex densification (here we use the default values for smax which is a 10km vertex distance in the reprojected map by default): v.proj box_latlong_10deg out=box_latlong_10deg_yes_densificationĮventually we can compare both reprojected maps: g.region vect=box_latlong_10deg_no_densificationĭ.vect box_latlong_10deg_no_densification color=redĭ. OGR interprets the string differently from PROJ.4 - internally it converts it to WKT format so I'm guessing that it requires the parameters to be specified, and because none are there it sets them to zero. Now we first reproject the map the “traditional way” (no vertex densification as in most GIS, here enforced by smax=0): v.proj box_latlong_10deg out=box_latlong_10deg_no_densification How g.proj works is it uses OGR functions to parse and validate the PROJ.4 string before converting it into GRASS format. Next we start GRASS GIS in a metric projection, here the EU LAEA: # EPSG 3035, metric EU LAEA: # generate the box according to current computational region: Fossies Dox: grass-8.2.0.tar. # for the ease of generating the box, set computational region: About: GRASS (Geographic Resources Analysis Support System) is a raster- and vector-based GIS, image processing system, graphics production system and spatial modeling system.
Proj info of pennsylvania grass gis download#
ExampleĪs an (extreme?) example, we generate a box in LatLong/WGS84 (EPSG: 4326) which is of 10 degree side length (see below for screenshot and at bottom for SHAPE file download of this “box” map): ~]$ grass70 ~/grassdata/latlong/grass7/ The needed improvement has been kindly added in v.proj by Markus Metz. The projection information is taken from the current PROJINFO files, as set and viewed with g.proj. This reduces the reprojection error for long lines (or polygon boundaries). PROJ pipeline for coordinate transformation DESCRIPTION¶ r.proj projects a raster map in a specified mapset of a specified location from the projection of the input location to a raster map in the current location.
This will override any datum contained in the input co-ordinate system, and discard any datum. Successful grass establishment has been impeded by overgrazing and. PROJ descriptions have very limited support for specifying datum names), a GRASS datum abbreviation can instead be supplied using the datum parameter. Expanded use of remotely sensed information for data collection helps in measuring. GRASS GIS 7 just got better: When reprojecting vector data, now automated vertex densification is applied. If datum information is incorrect or missing in the input co-ordinate system definition (e.g.
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