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.
14
votes
3answers
288 views
How to do kernel density estimation with a physical barrier/ boundary in QGIS?
Does anyone know of a programme that will allow kernelling that takes a boundary into account in its calculation rather than simply masking areas that are impossible?
So far I have found:
GME add on ...
0
votes
2answers
60 views
How do I reproject one raster to match another's in GRASS
I have two raster layers, A and B, which have information about the same location but have different projections and datums.
How can I reproject layer A to match the projection and datum of layer B?
...
0
votes
2answers
82 views
Error from ps.map in GRASS. How to fix?
I'm trying to learn how to use ps.map in GRASS. I thought that running it in interactive mode from the command line would be a good place to start, but I'm getting the following error:
> ps.map ...
6
votes
1answer
235 views
How to perform unsupervised classification of LANDSAT time series using Grass?
I'm using GRASS to perform an unsupervised classification on a time series of LANDSAT images (monthly temporal res, over 30 years), in order to compare land cover change in a particular area.
I'm ...
4
votes
1answer
76 views
Help installing add-on in GRASS, I get an error message
My Grass gives me this error message, Grass_info_error(4816,1):'make' required. Please install 'make' first. This happens when I attempt to fetch an add-on (r.viewshed). What am I doing wrong? and ...
3
votes
1answer
77 views
Autocorrelated DEM with QGIS or Grass
I was wondering if there is a way to make an Autocorrelated DEM within QGIS or Grass. I am looking to do this with stereo aerial photography. I am able to do this with a number of COTS tools, but I ...
2
votes
1answer
66 views
GRASS : r.resamp.rst error : “Not enough disk space--cannot write files”
Today, I am confronted to a difficulty I cannot manage.
When I try to use the tool "r.resamp.rst", it gives me as answer:
*r.resamp.rst input=map@PERMANENT ew_res=11 ns_res=11 pcurv=curv
...
2
votes
1answer
62 views
Issue while running grass from subprocess
I have a map based web application using geodjango. I needed to display the crime hotspots within a selected polygon area. I found that v.kernel is very good for generating heatmaps/hotspots. So in my ...
1
vote
1answer
53 views
Showing map in Grass Layer Manager/Map Display via Python
I've created some raster(tif) maps using Grass libraries in Python. I want to opem them automatically in Grass GIS Map Display or Layer Manager after creation. I don't want to use GUI for this. What ...
0
votes
1answer
17 views
how to loop grass command in python and put variable in output file
anyone,
first day Grass programming with python scripting;
first prob;
simple I want to reclass the same raster several times;
and save the file with the value loop variable at the end ...
can not ...
0
votes
1answer
31 views
Problem opening GRASS GUI: libgeos-3.3.6.so: cannot open shared object file:
I have been using GRASS to process some Landsat imagery but very recently, and as far as I am aware - after having done nothing different or changing the settings, I am trying to use GRASS and on ...
0
votes
1answer
83 views
Sextante grass folder incorrect?
What is the correct grass folder in Sextante? I alway get this message:
The specified GRASS folder does not contain a valid set of GRASS
modules. Please, go to the SEXTANTE settings dialog, and ...
0
votes
1answer
44 views
Why can't I load more than 12 elevation files into NVIZ?
I have a large set of rasters in a GRASS mapset, which I would like to use as frames in an animation, visualizing the raster data as elevation. NVIZ is an obvious tool for this, but I'm having trouble ...
0
votes
1answer
108 views
How do you use 'reclass' in GRASS?
It could be user error, but for some reason, the reclass tool is just hanging and hanging...
QGIS 1.8
Compiled against GDAL/OGR 1.9.2
Ubuntu 12.04.1
Running the tool from the Sextante toolbox
Input ...
5
votes
0answers
206 views
SEXTANTE toolbox - GRASS error
I am trying to use the SEXTANTE module GRASS (and SAGA) for vector analysis but whatever function I use I always get the same error:"Could not load layer: G:/closest.shp
Check the SEXTANTE log to look ...
4
votes
0answers
52 views
Is r.cost equivalent to diffusion interpolation with barriers?
I want to perform interpolation using cost distances rather than euclidean distances similar to Greenberg et al. (2011). In that paper they use r.cost in GRASS to compute cost distances for each ...
2
votes
0answers
32 views
How to create a topologically correct dataset in PostGIS (with GRASS)?
I have shapefiles which I have loaded in postgis and now i am trying to use geometric function in postgis like ST_intersect and they fail because the data is not topological correct.
I have tried to ...
2
votes
0answers
84 views
Flow modeling and FOSS GIS; lahars and HEC-RAS
What are the options for FOSS flow modeling of dilute debris flows in QGIS or GRASS?
Have you, or can you refer me to studies where the authors, tested these models/plugins/functions/etc. for use in ...
2
votes
0answers
53 views
How to join nodes to network lines ( and not the other points)
I'm trying to do a shortest path analysis on my network. In order to prepare the network and attach polygon centroids to the roads, I used GRASS' V.NET operation=connect. the problem with this ...
2
votes
0answers
42 views
Temporal GRASS GIS framework
I am trying to follow the tutorial posted here. When I get to this part "Extraction of seasonal mean temperature" and run this code:
t.rast.extract \
input=temperature_mean_1950_2011_seasonal \
...
2
votes
0answers
116 views
Topology problems with QGIS/GRASS
*edited file links below
I'm working on several NGO projects at the moment, all of which are reliant on being able to use a district level map with some 490+ features, and I am running into some ...
2
votes
0answers
88 views
Export to shapefile qgis
I am trying to develop hotspot map showing point density in our gis based web application. After searching for an option I have decided to use v.kernel command. I have a table containing some point ...
2
votes
0answers
149 views
GRASS GIS - r.water.outlet - What is my mistake?
I'm new to GIS - more so in GRASS GIS. I installed GRASS GIS 6.4.3svn in my Windows 7 machine. No problem in installation.
Downloaded SRTM-Geotiff file
Location, Mapset all o.k
Used r.in.gdal to ...
2
votes
0answers
263 views
Simulate flood to assess Asset inundation footprints
I am trying to evaluate a number of flood gauges to assess at what levels of river height different flood risks would need to be issued. The gauges are currently set to warn of flood a couple of ...
2
votes
0answers
108 views
How to fix Graphserver warning “osmdb has no edges!”?
I'm really new to GIS.
I have some shapefiles data that I'm trying to import in graphserver. I'm doing:
gs_osmdb_compile output3.osm output3.osmdb
And the result is: WARNING: osmdb has no edges!.
...
1
vote
0answers
24 views
GRASS v.overlay.or Error when trying to split a polygon with a line
I am using the Grass plugin in QGIS for Windows (1.8.0). I am trying to split a polygon with a line feature. I am using the v.overlay.or function within the QGIS Grass plugin. I have the line layer ...
1
vote
0answers
59 views
GRASS Plugin to QGIS error
I am installing QGIS and GRASS as part of an FOSS GIS class I'll be teaching this summer. I used the OsGeo4W installer. This installer has always worked flawlessly for me except on the machines at the ...
1
vote
0answers
42 views
How to create the fuel models & live fuel moisture rasters for Wildfire simulation?
Has anybody done wildfire modelling in GRASS? Where could I obtain / how do I create the fuel models and live fuel moisture rasters to determine rate of spread (r.ros)?
1
vote
0answers
17 views
How to remove coastlines from Admin 0 data set using GRASS?
I have a set of international borders that I would like to overlay on top of a different data layer that represents coastlines ("land" essentially). I would like to convert my Admin 0 polygons into ...
1
vote
0answers
85 views
Heat Map trouble: Is this a data formating problem?
I'm playing with the heat map plugin with QGIS. I've run through QGIS tutorial:
http://docs.qgis.org/html/en/docs/user_manual/plugins/plugins_heatmap.html,
using the airports data set as explained ...
1
vote
0answers
59 views
GRASS python script runs twice
Is there a reason that every script I have written for GRASS in python runs twice? I start them using the GUI script launcher tool, and they all begin with:
#!/usr/bin/python
import grass.script as ...
1
vote
0answers
81 views
How to handle/ avoid intersect errors when clipping the difference between two layers?
Using QGIS + Grass, I've added a shapefile of coastline and islands to my map.
I then buffer this shapefile to create a coastal zone of a known width. At this stage the buffer consists of the ...
1
vote
0answers
73 views
i.maxlik cannot read i.class output signature file
I'm trying to perform a supervised classification using i.class. I'm then using i.maxlik, but this is returning the following error:
GRASS 6.4.3svn (India_01):~ > i.maxlik group=test_group@test ...
0
votes
0answers
26 views
GRASS - Creating an Attribute Based on Driving Distance
Is it possible to calculate the driving distance for each node of one layer (fire stations) to each node of another (address points)? After doing so, I need to sort all of the distances from shortest ...
0
votes
0answers
56 views
Grass won't import shapefiles
I have a problem involving the import vector data command, specifically importing shape files. I installed QGIS on a pc at work and there I could import shape files into GRASS GIS 6.4.3RC2 (which is ...
0
votes
0answers
34 views
SEXTANTE “could not load layer:…”
When I try to do a GRASS command via SEXTANTE in Qgis I always get the error:
"Could not load layer:...." check log file
Does not matter wether it should be saved in temp or another folder.
I found ...
0
votes
0answers
47 views
HELP! Starting up GRASS - Error messages.
I am just trying to start using GRASS, but am having problems setting up.
This is the error message I get:
WELCOME TO GRASS Version 6.4.2 2012
1) Have at your side all ...
0
votes
0answers
20 views
query for adjacent polygons in GRASS?
i need to create a table of each district in india's adjacent districts.
i found this query but couldnt get it to work for me: SELECT p1.PK_UID, p1.Name FROM Polys p1, Polys p2 WHERE p2.PK_UID=1 AND ...
0
votes
0answers
77 views
qgis plugin: “WindowsError: [Error 6] The handle is invalid”
OS: Windows 7 64bit
GIS: QGIS 1.8 (qgis.org/downloads/QGIS-OSGeo4W-1.8.0-2-Setup.exe)
path variable:
GISBASE=C:\Program Files (x86)\Quantum GIS Lisboa\apps\grass\grass-6.4.3RC2
...
0
votes
0answers
89 views
Help in GRASS/QGIS/Python
I have Idea about ArcGIS, and a bit of QGIS and zero programming knowledge, which I am trying for thesedays. I saw GRASS GIS and have started working with shapefiles, which are not being loaded... :( ...
0
votes
0answers
43 views
Add GRASS Addon to Sextant within QGIS
I have successfully installed r.viewshed as an add-on in GRASSS 6.4.2. I would like the command to show up in the list of algorithms within Sextante. Is there a way to make Sextante "aware" of ...
0
votes
0answers
48 views
Why don't libgrass.so.1.8.0 and libqgissqlantconnection.so.1.8.0 load?
I have compiled Qgis 1.8 at Ubuntu 12.10, but some phyton plugins does'nt work, like sextante.
Trying to solve this problem, some files don't have been load. They are: libgrass.so.1.8.0 and ...
0
votes
0answers
43 views
How to begin with tool development for GRASS gis or QGIS GRASS
I wanted to begin with customized tool development in Grass GIS or QGIS grass. How should i begin in to develop the tool. I search a lot in google search engine for begin with tool development in ...
0
votes
0answers
28 views
Why are there strange black and white rows and columns in my aspect map?
I would have a problem with aspect map in GRASS. I'm not an expert, so I think you easily can help me. I have created this aspect map, from dtm, but the result was an image with strange black and ...
0
votes
0answers
51 views
GRASS i.landsat.toar returns empty raster
I am trying to use the GRASS module i.landsat.toar.
Currently the files created are empty and it spits out:
So it seems that it is not picking up something? The location is set to the extent of ...
0
votes
0answers
211 views
How to resample a raster in QGIS?
I've got a boundary file that I would like to resample the raster file from a 30m grid to a 10m grid inside the boundary file. When I try and do it in Qgis or Grass all I get is one big raster cube ...
0
votes
0answers
109 views
Making a Bridge Classification tool in GRASS GIS
I'm working on a tool for classifying bridges with GRASS. I have been using examples online but I've come to a standstill as how to actually make this tool in GRASS. I have my raster of my area and ...
