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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6
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2answers
1k 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
6k 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 ...
11
votes
4answers
4k 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
736 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
592 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
2k 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 ...
3
votes
1answer
2k 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
1k 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 ...
63
votes
6answers
32k views

How to build effective heat-maps?

Using ArcGIS, QuantumGIS, Grass, and/or GVSIG What are some of the tools and processes involved in building effective heat maps? What are the plugins involved? What are the major data requirements? ...
9
votes
5answers
2k views

Are there any open source tools to detect and fill sinks on a DEM?

Are there any open source or inexpensive tools to detect and fill sinks on a DEM? ArcGIS Spatial Analyst is just out of my price range.