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.

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2answers
656 views

Altitude Above channel in GRASS 6.4

i'm fairly new to the GIS world and GRASS (come from econometric background), i would like to do some species distribution modeling using R and GRASS. So i started to read the book of Tomislav Hengl ...
7
votes
1answer
416 views

Saving Command History/Outputs to a file - GRASS

Is there any way to save the commands typed and the outputs obtained in terminal under GRASS GIS to a text file? I have read that GRASS saves history for each mapset but I have no much idea about how ...
3
votes
1answer
422 views

Slope, aspect and beam in R.Sun (GRASS)

I'm starting to mess about with the solar radiation packages of GRASS and ArcGIS and have become rather stuck on the GRASS side of matters. I have a DSM area, and that is feeding into GRASS well ...
4
votes
1answer
121 views

Export Region definitions - GRASS GIS

I use two different Landsat datasets in different computers. But the region settings I work is the same. Is it possible to export the region settings in the form of a file in GRASS?
3
votes
1answer
266 views

Problem in r.resample

When I run r.resample to crop a map by using a vector and a mask, the resulting map has the same shape as the vector that I used but does not replicate (exactly) the portion of the raster map that I ...
4
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2answers
263 views

How to select a subset of separate bands in GRASS GIS?

As you know landsat data has separate files for different bands. Creating a subset is a wise option to work on region of our interest. Therefore, I used this method to subset my image - d.zoom || ...
3
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2answers
867 views

How to delete a base map in GRASS?

I'm trying to delete a map that I used as a mask before, but I cannot delete it using g.remove. It displays this: g.remove rast=raster_Mnorzagaray@PERMANENT [raster_Mnorzagaray@PERMANENT@PERMANENT] ...
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1answer
583 views

Is there any pseudocode for MFD (multiple flow direction) algorithm available?

Still stuck with the simulation system, is there any good pseudocode for the multiple flow direction (MFD) algorithm? I read a pseudocode example and implemented it, however the simulation was linear: ...
1
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2answers
370 views

How to compile in Fortran in order to use an add-on in GRASS?

I need to use the r.inund.fluv add-on in GRASS. I installed the gfortran compiler in order to use the script. The problem is, I do not know how to compile the files in gfortran. Im using windows Here ...
7
votes
1answer
967 views

GRASS - Will r.to.vect work on this scanned map?

Total GRASS noob here. I have several very large hand contoured maps to digitize, and this thread intrigues me. In the past I have spent hours upon hours digitizing these maps and revisions in ArcMap. ...
4
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2answers
3k views

How to install add-ons in GRASS?

How do I install the r.inund.fluv script in GRASS? https://svn.osgeo.org/grass/grass-addons/grass6/raster/r.inund.fluv/
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votes
1answer
641 views

How to use GRASS with HEC-RAS?

I am trying to use HEC-RAS for the flood modelling of my flood simulation. How do I use the text file output of HEC-RAS with the GRASS script r.inund.fluv?
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1answer
230 views

The resulting maps from a r.mapcalc script is not computed properly

This post is a continuation of my other post Why is my controlling shell script not working?. I created another post because this contains a separate issue that I encountered with the same scripts of ...
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vote
3answers
409 views

d.out.file is not working

I'm trying to use 'd.out.file' to save the displayed map to a PNG file. It failed and produced this message: "Command 'd.out.file' not yet implemented in the GUI. Try adding it as a command layer ...
0
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1answer
274 views

How to export a png file from a raster file? r.out.png has an error

I used r.out.png to export a png file, but it produced this error: (Sun Feb 27 00:26:32 2011) r.out.png input=raster_bulacanElevation ...
3
votes
1answer
809 views

Is there a way of cutting a raster map that is displayed in the GRASS GIS Map Display?

I have a raster map that I generated from cropping/masking from a bigger raster map. It produced a map with only a portion of not null values. I only want to have a map that is zoomed in to the ...
8
votes
3answers
2k views

R: Download a large DEM, change projection, and adjust to smaller scale

This is a process that takes just a few seconds in GIS software. My attempt to do it in R uses a large amount of memory then fails. Is there something wrong in my code, or is this just something R ...
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1answer
402 views

Grass GUI integration

Is it possible to embed the GRASS map display to a C# application? I know that a PNG image can suffice but to make the application more interactive it could perhaps be integrated. In essence I would ...
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1answer
339 views

Shell script commands

I have this shell script: #!/bin/sh r.mapcalc water = 120 d.rast water i=1 while [ $i != 100 ] do n=1 while [ $n != 10 ] do r.mapcalc < water.mapcalc d.rast ...
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1answer
243 views

Why is my controlling shell script not working?

I updated my post after I resolved the previous errors, but additional errors were produced. I want to create a controlling shell script that contains water.mapcalc within it. The problem is, I do ...
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vote
1answer
373 views

How to link an application to grass?

I am creating an application (C#) and I want to connect it to GRASS, mainly run grass scripts from my application. This might seem to be a repeated question however I am thinking of the possibility ...
12
votes
1answer
1k views

How do you use GRASS's v.kernel?

I am flummoxed on how to use GRASS's v.kernel. I have a vector layer of around 2.5 million points. I want to make a heat map using v.kernel to show concentrations, since I have variable instances ...
2
votes
2answers
149 views

Can the arrows produced by the d.rast.arrow GRASS script be queried or stored?

I have created a map with the flow directions using the d.rast.arrow. Can i query on the map to know where the direction of the arrows are? I am going to use the arrow directions in an algorithm. Or, ...
4
votes
2answers
1k views

How to delete a map from the GRASS interface?

I want to delete a map that I generated from GRASS. I tried removing a map from the "Map Layers for each display" tab in the GRASS GIS Layer Manager, but it only removed the map from the list and not ...
3
votes
2answers
191 views

How to make the arrows in d.rast.arrow GRASS script visible?

I'm trying to create a Flow or directional raster map (with arrows) from an SRTM elevation map that I downloaded from CGIAR. I already created an aspectMap to be used for the d.rast.arrow. I used ...
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1answer
652 views

GRASS v.out.dxf 3D into AutoCAD

So continuing with my last question (Create 3D dxf with OGR) I have decided to give the GRASS option a go. I have imported my polylines into GRASS using v.in.ogr and converted them to 3D using ...
2
votes
2answers
122 views

GRASS 6.4.0 and GRASS 6.4.SVN

What is the difference between GRASS 6.4.0 and GRASS 6.4.SVN? Thanks
8
votes
4answers
1k views

Flood modelling insights

I am trying to create a flood modelling system. The system consists of two parts mainly a river flooding simulation and rainfall simulation. To do this I am running the latest version of GRASS 6.4. ...
1
vote
1answer
280 views

Error in r.terraflow

I used r.terraflow.short in GRASS, but it displayed this error: r.terraflow.short elevation=raster_bulacanElevation \ filled=raster_bulacanElevationFlooded1 \ ...
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2answers
469 views

How to create GRASS scripts in C# in Windows

Most of the tutorials that I have seen are under Python and Linux. Is it Possible to create GRASS scripts in C# or atleast in Windows. I can create scripts using a different language as a compromise ...
1
vote
1answer
155 views

How to resolve GRASS error “Execution failed: 'gproj -p' ”?

I installed the WinGRASS-6.4.0-1-Setup.exe 55M from http://grass.osgeo.org/grass64/binary/mswindows/native/. I'm using a x64. After installation, I tried opening the demoLocation but it failed and ...
0
votes
1answer
123 views

How to create a new table for a vector file?

I will use v.db.connect but i want to use a new table, and not an existing table to connect it to. What is the GRASS script for it? Thanks!
4
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3answers
744 views

How to get the elevation of the areas in a raster file from SRTM?

I have an SRTM elevation map. How do I get the elevation of each point in the map? I am using GRASS. Is there a GRASS script to do such?
3
votes
1answer
402 views

How to get the Flow or directional raster map using GRASS?

Aside from using r.fill.dir in GRASS, is this the script to produce the Flow or directional raster map? Is this the output for the script ...
1
vote
1answer
183 views

Why is the geonames not loading?

I want to import a geonames file. I downloaded the geonames .txt file from http://download.geonames.org/export/dump/ I used: v.in.geonames input=PH.txt output=ph but it displayed ...
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1answer
897 views

How to select a raster file that is under a polygon in a vector file?

I am using: v.db.select map=PHL_adm1 where=NAME_1='Bulacan' My vector map is over the raster map. I want to select the part of the raster map under the polygon(NAME_1='Bulacan') of a vector. Is it ...
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1answer
2k views

How to combine a vector and a raster file?

I want to combine a raster and a vector file. After combining, can I query on the resulting map to obtain a specific area? How?
4
votes
1answer
311 views

How to know contents of column names in GRASS?

I am using GRASS to extract a specific area from a vector map. Here is the script that I am running: v.extract PHL_map out=makati where="AREA_NAME = 'Makati" The problem is, I don't know what are ...
2
votes
2answers
556 views

How to query data from a vector map (shapefile)?

We want to obtain the specific place of the boundaries of a shapefile. We want to be able to get the points of each polygon corresponding to a specific place in order to use these data in an ...
6
votes
1answer
870 views

How to calculate difference in altitude along lines using GRASS?

Using SRTM altitude information and OpenStreetmap roads, I want to calculate altitude differences (sum of meters uphill and downhill separated = two values) per road element. What would be the ...
14
votes
3answers
2k views

Rubber sheeting in GRASS or QGIS

We are in the process of getting our property boundaries corrected and a side effect of this is that we need to move any assets that have been drawn relative to the property boundaries, so they are ...
12
votes
4answers
4k views

Shaded relief from DEM in GRASS and QGIS

I have been trying to get a good looking shaded relief model out of GRASS and Qgis for a day or so now and just can't seem to get it. The biggest problem I'm having is the valleys look like ...
6
votes
2answers
958 views

Moving raster to different mapset GRASS GIS

I have a raster DEM that I created in one mapset but I would like to copy it to another mapset for another purpose. Is this possible within GRASS or can I just copy some files over in the ...
4
votes
2answers
4k views

How do you Turn on the GRASS plugin in Quantum GIS?

I downloaded and installed Quantum GIS 1.5.0 with GRASS using the OSGeo4W installer on my Windows XP machine. Unfortunately, when I go to Plugins>Manage Plugins I cannot find the GRASS plugin. When ...
9
votes
4answers
3k views

Code to calculate elevation profile along line from a DEM

Given a DEM (Digital Elevation Model) say in and a line (x1,y1) --> (x2,y2) (paired coordinates (x,y)), how can one calculate the elevation profile or cross-section projected on that line ? I am ...
5
votes
1answer
596 views

What is north-up projection?

How do I know what projection to use for north-up or 0 rotation? I have a gtiff (ND83-nf) that gives me the error when importing to Grass. Should I re-project or recreate the image with the rotation ...
2
votes
1answer
523 views

How to import SpatiaLite data into GRASS?

How can I import SpatiaLite tables into GRASS? Are there any restrictions I should be aware of? How does GRASS cope with columns that don't have a specific type (Sqlite tends to create such columns ...
7
votes
3answers
1k views

How to interpret GRASS v.kernel results?

GRASS manual reads: v.kernel - Generates a raster density map from vector points data using a moving 2D isotropic Gaussian kernel ... Ok, but how do I interpret the results? I understand that ...
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vote
1answer
1k views

GRASS GIS: How do I run a batch (bash?) script?

I am in a GRASS database (in command shell), where I want to run a loop function. For example, I want to do an operation on many raster files that are in the database. I know this must be done through ...
8
votes
1answer
751 views

How to apply a Majority filter in GRASS GIS?

I was wondering if someone could help me write a majority filter for GRASS GIS. I have this map (see below) which I need to run a filter over to make the red areas a bit more dominant. I know I can ...