GRASS GIS (Geographic Resources Analysis Support System) is a free, open source geographical information system (GIS) capable of handling raster, topological vector, image processing, and graphic data.
1
vote
2answers
78 views
v.dissolve (and other scripts) not in GRASS path
I see that I have the v.dissolve module in my grass64/scripts dir, but it is not found in my path from the GRASS command line. I have the GRASS_ADDON_PATH environment variable set:
...
4
votes
1answer
99 views
Would it be possible to construct a stand-alone grass.script python package?
I would like to migrate dependency on ArcPy to grass.script without requiring the full installation of Grass. Would it be technically possible to have a portable directory containing grass.script and ...
3
votes
2answers
524 views
How to combine polygons in a vector with GRASS?
I need to combine polygons of similar geological classes which are stored in a vector file called geology. I was looking for somethiing like "union selected features" or similar. In the GRASS Book ...
1
vote
1answer
169 views
How can GRASS export an .flt file?
I am using GRASS and connecting it to another application. The other application needs an FLT file of the raster map which I should export from GRASS. The other application only reads FLT files. Can ...
1
vote
1answer
80 views
How do I convert my coordinates to the limit of geographic region (outer edge)?
I am trying to use r.in.bin. The parameters of north, south, east, and west needs values:
north=float
Northern limit of geographic region (outer edge)
south=float
Southern limit of geographic region ...
3
votes
1answer
852 views
Create filled contour map with GRASS
Background
I'm trying to make contour/isoline/isochrone maps to show what areas are within walking distance to schools for my pet project to help with the Safe Routes to School program. I followed ...
4
votes
1answer
169 views
Need to remove small areas, but only if they do not have adjoining boundary
I'm generalizing some lat/lon data in grass64 and as a precursor to the generalization, I am removing small areas from the data using 'v.clean'. The following command is working well:
$ v.clean ...
1
vote
2answers
139 views
Can r.mask be called from a batch file?
I am using a shell script that is called by a batch file. The shell script contains the GRASS scripts that I am using for my program. Every time I use the r.mask script, it displays the error r.mask: ...
3
votes
1answer
59 views
Can two versions of GRASS be installed in a computer and still run independently?
GRASS 6.4.0 is currently installed in my computer. The script that I am trying to run is present in 6.4.1. It is stated in my previous post. If I installed 6.4.1, will my 6.4.0 still run? I don't want ...
3
votes
1answer
285 views
How to make a transparent background image using r.out.png?
Can the white background of the r.out.png of GRASS be changed to transparent?
17
votes
3answers
2k views
How to smooth a DEM?
I have a SRTM DEM and I want to create a shaded relief from it. I created the shaded relief in GRASS and the result is very nice, but a little rough becouse the area is near flat and the DEM is 90m in ...
8
votes
2answers
518 views
How to convert a vector boundary to a raster map?
I need to output a PNG file of a raster map overlayed with boundaries present in a vector map. The problem is, the r.out.png script only exports a raster map. My boundaries are in a vector format. ...
10
votes
3answers
538 views
How to simplify a routable network?
I have a network graph that I need to simplify in the sense of reducing the number of edges. The idea would be to merge nodes that are located close together and remove the connecting short edges.
...
6
votes
1answer
2k views
How to create a point along a line given distance
I have been given a non-spatial database which contains the names of lines which I have a shapefile for. The database also has names of points and the distance of each point from the origin along the ...
0
votes
1answer
122 views
Problem running i.gensigset in Grass. Any ideas?
It just returns ERROR: Unable to create signature file. It doesn't say why... Anyone had this before and found a solution?
1
vote
2answers
404 views
How to import .flt files into GRASS?
I am trying to import a raster file (.flt) into GRASS. The raster file (.flt) was generated from HEC-RAS. The said raster format cannot be imported into GRASS (it shows the error "file not ...
3
votes
2answers
142 views
Can GRASS v.net.iso split between nodes?
Can GRASS's v.net.iso module split networks between nodes on the network, i.e., if I am finding the area within a cost of 400, and there is a line segment with a cost of 800 leaving the center node, ...
3
votes
1answer
272 views
Standard Colors for Landcover Maps
I have classified Landsat images into five classes - A variety of Palm, Water bodies, built-up/open area, other vegetation and miscellaneous. I used GRASS GIS for the process and the final classified ...
4
votes
2answers
322 views
Monthly Average Solar Maps (R.Sun) in Grass
I'm trying to create monthly average maps as described in R.Sun in Grass. I have my DSM. In reading the page on OSGEO it mentions that it is possible without showing how. Ideas? I assume I will need ...
2
votes
1answer
317 views
Scripting in GRASS
Can anyone suggest me web-links to learn scripting in GRASS GIS (its utilities, examples etc.) other than those available in GRASS official Wiki/Sites?
2
votes
1answer
405 views
How to clean vector segment intersect errors in GRASS
I'm using GRASS to process a vector map.
When I export back to .SHP and do a 'Check Geometry Validity' in Quantum GIS it lists several errors of this type...
3,segments 199 and 203 of line 0 ...
2
votes
1answer
661 views
How to handle multiple layers when importing a polygon shapefile into GRASS?
When I import a shapefile into GRASS, it seems to arrive as 3 layers.
I.e. they appear in the qGIS toolbox browser as:
myMap 0_polygon, myMap 1_polygon, myMap 2_polygon
Is there a way to merge ...
4
votes
1answer
1k views
Convert shapefile lines to a polygon in GRASS
I have a shapefile of a map that is the outline of a number of islands. I would like to convert the lines into polygons (ie all islands filled in) using GRASS. I searched on how to do this with GRASS ...
5
votes
6answers
365 views
Southern hemisphere projections for Landsat upsets GRASS
Hi All
does anyone have the last word on why Landsat scenes don't project in the southern hemisphere. This causes no end of trouble in GRASS, less so in QGIS.
What I mean is, take an original scene ...
2
votes
2answers
287 views
Layer Stacking in GRASS
Similar to layer stack feature in ERDAS what functionality is available in GRASS. I am aware of r.composite, but it can accept only 3 layers. To obtain a stack of more than 3 layers what can be done?
2
votes
1answer
85 views
Can the concentration of values in a raster map be known?
I have a generated raster map containing different flood levels. Is there a grass script to determine the percentage of values in a raster map? I'm thinking of using r.mapcalc to solve this, but I'm ...
1
vote
0answers
257 views
gdal-grass plugin for gdal 1.8 [closed]
I'm facing a big issue...i moved from the ubuntugis version of grass to the svn one.
I managed to compile the svn (releasebranche6.4) version nicely but i can't download the gdal-grass plugin for ...
1
vote
1answer
207 views
Command r.sunmask in GRASS
I have hypsometric model of relief, and I need to visualize shadows. I was suggested to use GRASS command r.sunmask, so I tried to set time values and run command, but it gives me an error
"ERROR: ...
2
votes
1answer
284 views
Compilation of GRASS 6.4.trunk on Win7
you may have seen my other posts, at the point now where I am trying to use the landsat plugins in a lower version of GRASS. Markus N noted that the 6.4.2 might be better, since that is not out yet I ...
1
vote
1answer
319 views
Win7 GRASS 7 & i.landsat.toar
Hello has anyone got experience running i.landsat.toar ?
The output files I get are empty, the command takes but a moment to complete. However when run in verbose mode all the calculations are done, ...
1
vote
2answers
322 views
GDAL-GRASS building fails
When I run ./configure --with-grass=/usr/local/grass-6.5.svn/ I get the following errors:
..........
checking for gdal-config... /usr/bin/gdal-config
using /usr/lib/gdalplugins as GDAL shared library ...
3
votes
1answer
181 views
SVN Version of GRASS and QGIS
I have GRASS6.5 SVN installed and wanted to go for SVN installation of Quantum GIS in Ubuntu 11.04. So as instructed in QGIS Wiki, I added the qgis repository to my sources.list file. Now I am able to ...
6
votes
3answers
313 views
Grass v.rast.stats returning null values
I have a vector layer (polygon) and a raster layer. The raster layer holds values for height above bald earth in a field called "value". I'd like the vector layer to inherit either the mean or the ...
3
votes
2answers
166 views
Is there a shortcut in GRASS for importing vector files?
Is there a keyboard or command shortcut in GRASS for importing vector files? If you know link where I can find maybe whole list of shortcuts for GRASS, that would be awesome. Thank you.
4
votes
2answers
528 views
What's a good toolchain to reproject some PNGs in plate carre to UTM?
I have some PNGs produced from Canadian DEM data. They're 1201px by 1201px heightmaps. Each one represents one quarter of a degree latitude and one quarter of a degree longitude.
But I want to work ...
4
votes
4answers
915 views
Where can I find a tutorial for installing an addon to GRASS GIS that a six-year-old could understand?
I want to use the r.stream.distance addon in GRASS GIS 6.4 on ubuntu 10.04 (64 bit).
I've installed grass from the repositories and that works fine but I can't seem to figure out how to install this ...
4
votes
1answer
544 views
How can I calculate the vertical distance to the nearest water?
Summary:
I would like to create a raster where each cell contains the vertical distance to the nearest water (a decent approximation would be acceptable). The problem is that I'm not sure how to go ...
10
votes
4answers
712 views
Large shapefile to raster
I have a large shapefile (1 gb) and need to rasterise it. I have tried the following already.
1.) Import it into GRASS using v.in.ogr this failed with the error message: ERROR: G_realloc: unable to ...
8
votes
1answer
484 views
Kriging on GRASS+R
I'm trying to do a groundwater elevation map with an Ordinary Kriging on R, but always resulting on the lack of memory
cannot allocate vector of size 146.5 Mb
allocation (windows xp 32bit). ...
3
votes
3answers
502 views
How do I draw on a vector map in GRASS?
I have a vector map that has two lines. I want to have the two connected. Is there a way for me to draw a line to connect the two? I am using GRASS gis by the way. The two lines that I want to connect ...
3
votes
3answers
292 views
Can a raster map in GRASS be saved in JPEG/BMP format?
I'm trying to save a raster map in GRASS in jpeg/bmp format without using the GUI for d.out.file/d.save. Is there a script to do it? I tried r.out.gdal but it produced a map that is black and white.
11
votes
2answers
1k views
Is there a way to automate the preprocessing of LANDSAT data?
I'm currently enrolled in a remotesensing course, using LANDSAT data.
Part of my course is about standardizing the scenes based on radiance values. I assume that because this is such a tedious task, ...
5
votes
2answers
443 views
Raster to Vector: Displaying classes in Vector Layer - GRASS GIS
I use Maximum Likelihood classification to classify Landsat image into two landuse classes - one of my interest and rest including all others. Inorder to assess the accuracy I export it in vector ...
2
votes
1answer
141 views
Error in using/installing v.digit: GRASS GIS
When I wanted to edit a shapefile in GRASS I got this message:
Unable to start wxGUI vector
digitizer. Do you want to start TCL/TK
digitizer (v.digit) instead?
Details: No module named
...
1
vote
1answer
264 views
How to use r.patch with two maps having different colortables?
I am using r.patch to combine two raster maps in order to fill in the null values of the other. Is there a way to use r.patch but still maintaining the colortables of the separate raster maps? I do ...
0
votes
1answer
296 views
How to convert .ps to .png in a ps.map script?
I already managed to create a .ps file. How do I convert it to .png using a GRASS script?
4
votes
5answers
455 views
How to save a raster and vector into a single PNG file in GRASS?
I am trying to save a raster and vector into a PNG file. The vector is overlayed on top of the raster map. I was only able to save the raster file into a png using r.out.png but without the vector.
3
votes
1answer
344 views
spgrass6 and GIS_LOCK
I would like to thank's everyone first, i learn a lot here (gis.stackexchange) about GIS. I have one question about the use of GRASS within R session, i'm able to do some basic task, but i have one ...
5
votes
2answers
1k views
How to return raster values based on polygon (shapefile) boundaries in QGIS?
How to return raster values based on polygon (shapefile) boundaries in QGIS?
Is this an elementary question, because I am finding it hard.......
Ideally I would like a neat workflow as I am likely to ...
0
votes
1answer
96 views
d.legend script is not working
I'm using the d.legend script in grass but it is not working. I can only show/hide the legend using the 'add legend' option in the Map Display window in GRASS. I need to make d.legend script to work ...
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