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.

learn more… | top users | synonyms

0
votes
1answer
24 views

GRASS Gis v 6.4.4. KeyError: 'version' when start

When I try to start the GRASS it gives me the following error GRASS 6.4.4 (Hellas):~ > ERROR: MAPSET Hellas - permission denied Traceback (most recent call last): File ...
1
vote
1answer
27 views

How to visualize a point cloud in 3D with GRASS?

I'm new with qgis and grass so I'm sorry if there is a straightforward answer for this question but I can't seem to get it done. I've imported a pointcloud into qgis from a datafile. Now i'd like to ...
0
votes
1answer
20 views

GRASS 7.0.0beta3 / statistics change after TIF import?

I'm new to this forum, and pretty much a beginner with GRASS (7.0.0beta3 installed atm). So my question is the following: Statistics (mean, min, max) change quite a lot after importing a .TIF grid ...
0
votes
0answers
31 views

setting null values to 0 Landsat 8 Grass 7.1

I am working with Landsat8 images and need to run the albedo function in Grass 7.1.svn. In order to do this, I need to set the null values to 0 to eliminate the black border around the images. This ...
1
vote
1answer
25 views

Error in executing commands in GRASS GIS

I'm using Grass 6.4.3RC2. I have a problem because when I execute the command: r.radcov csv_file=cell_list_hataDEM_umts_amc_testTEST.csv dem_map-AlbSRTMdem@PERMANENT clutter_map=AlbClut@PERMANENT ...
0
votes
1answer
14 views

How to import and layer stack seperate ndvi bands to grass gis?

I have 20 separate single band NDVI files. I have to import this into GRASS and stack them into a single 20 band image. How can I do that?
2
votes
2answers
198 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
0answers
42 views

Hydropower Calculation

I have assigned the elevation and the volume flow to each point at a river (with v.to.db and v.what.rast). Now I want to calculate the Elevation difference between each pair of points and then ...
1
vote
0answers
21 views

How to load “soil types” in QGis?

I want to show soil transmissivity per pixel. Thus, I determine water holding capacity of each pixel (ignored other effective parameters). Respectively, I wonder, What is the soil data format and How ...
0
votes
1answer
54 views

r.composite gives blank image output in GRASS GIS

While running r.composite in GRASSGIS GUI command the image formed looks absolutely blank. The data I used is listed here below. IRS-LISS III Multispectral coverages. (i.e. band 2, 3 and 4 for Blue, ...
4
votes
2answers
180 views

95 percent volume contour

I generated, from point data, a kernel density map using GRASS, and I would like to identify the 95% volume contour in it. Is it possible in GRASS? Thank you
1
vote
0answers
99 views

Assessing Flood Hazard Risk Zones using DEM

My Question: What is the best effective way to quickly estimate flood hazard risk areas using DEM data? Ideally I am looking for guidance to move forward and perform this process over large areas ...
1
vote
0answers
59 views

Error when creating a new mapset with GRASS in QGIS

When I try to create a New Mapset with the GRASS plugin in QGIS I get an error or the program crashes. QGIS 2.6.1 (32-bit install, Win7). QGIS crashes completely when clicking "Finish" in the New ...
4
votes
1answer
67 views

How to calculate “water accumulated in each cell” using QGis?

I create channel network and catchment area from a DEM with SAGA GIS. I know that flow is starting from a cell to an other cell. Firstly, a cell is filled with water and then it is starting to flow ...
1
vote
1answer
25 views

How to do a looping for importing and interpolating a lot of LIDAR files?

I'm quite new to Grass Gis and I'm trying to make DEM (digital elevation model) for modelling flooding. I have 170 *.xyz files, which need to be scanned for extents (r.in.xyz -s input=...\filename.xyz ...
0
votes
0answers
30 views

Horton Stream Order as Category for r.fixed.segmetpoints with GRASS?

I'm working with Grass GIS. I want to use v.segment to set discrete, equidistant Streampoints (starting from each mouth). Since the water network is too large, it is impossible to define the rules ...
0
votes
0answers
30 views

How to decide when flood started depending on the rainfall data?

I created a raster with the point values (mm) of rainfall data by interpolation in the raster menu. So I have a raster rainfall data and a DEM. With this rainfall data and a DEM corresponding to ...
0
votes
1answer
57 views

Grass 7 on Ubuntu 14.04. Can't start Grass

I attempted to install GRASS GIS 7 on ubuntu 14.04 using these instructions. When I call grass70 from the command line I get a welcome message and a prompt to continue. I then get two error messages: ...
2
votes
2answers
26 views

Harvesting pixels using GRASS GIS

having a binary raster map of pixels of interest, a road network, and a target point, my goal is to get a raster map with network pixels having as value the number of pixels of interest they allow to ...
0
votes
1answer
44 views

Isochrone driving/public transport map : Grass or postgis?

I have to do Isochrone driving / public transport map. It would seem that the two better open-source solutions are grass and postgis. Could you tell me which one is the better? the easier to ...
1
vote
1answer
27 views

Calculate River Runoff Volume (Q) with GRASS

I want to calculate Hydropower between points at a River. I already created a Rivernetwork and the Accumulationmap (without weighting) with r.watershed. My next Step was to set equivalent points along ...
1
vote
1answer
30 views

GRASS 7.1 (dev.) i.landsat.toar error

I am working with Landsat 8 image acquired in 2014. I am trying to convert the raw image (DN) to Top Of Atmosphere Reflectance/Radiance (i.landsat.toar) in Grass 7.1 (still under development). The ...
0
votes
1answer
15 views

tutorial for deriving solar insolation estimates from high resolution Digital surface model

I want to estimate solar insolation using grass gis. I have a high resolution DSM generated from Large Format Digital camera.Being a novice in this field i Would like to have a tutorial and steps to ...
0
votes
1answer
20 views

How can I fill the category field in a raster using GRASS

I have a tiff file with land use data. The land use class in in the value field, but the label field is empty. Now I want to find out which is the area covered by each land use class, but GRASS does ...
0
votes
0answers
15 views

automatic extraction of dtm using grass gis

i have generated dsm using erdas lps tool which is in img format. i want to import this file in grass gis and extract dtm. can you please tell me how to input the data , in which format it should be, ...
1
vote
0answers
18 views

What is the background processing of rainfall thresholding?

I want to create a flood map using Quantum GIS. First of all I create catchment area (flow accumulation). Then, I delineate a Channel Network by applying a threshold to flow accumulation. So I want to ...
3
votes
1answer
378 views

Solar irradiation calculation using r.sun

I am trying to compute the global solar irradiation for a region and the run times seem to be a bit too high. I have as inputs a Digital Surface Model with the buildings and a Digital Terrain Model ...
0
votes
0answers
11 views

How to visualize insolation rasters over color orthophoto in grass

I have generated insolation time raster map using DSM, slope, aspect for day 100 and time 10.95 hrs using r.sun module in grass. The output insolation raster map (color table) i want to overlay on ...
1
vote
4answers
467 views

Determining gradient of road segment

I've a shapefile of roads data. It contains information about terrain of road segments, i.e., hilly, flat, undulating, etc. I want to determine gradient of every road segment. I know this might ...
0
votes
1answer
27 views

How to change the Map Units in Grass?

because v.segment measures all offsets in map units, i have to change it. (I want to put all of 50 meters a point) So I checked g.proj -p: -PROJ_UNITS------------------------------------------------ ...
1
vote
0answers
22 views

problem with running raster calculator in grassgis

When I was trying to do NDVI with grassGIS I faced a problem. I cannot run the raster calculation. When I looked to the command console I see that (Sat Feb 21 12:41:58 2015) r.mapcalc ddes = ( ...
1
vote
1answer
104 views

How to create a mosaic in QGIS with cutline and feathering for Landsat-8 imagery

1 - I have two scenes Landsat-8 RGB 6/5/4 and I need to mosaic them: 2- This is my cutline in polygon format that will smooth the overlapping area: 3 - So, I need to create a mosaic with ...
0
votes
0answers
16 views

Color polygon centroid according to attribute value in GRASS

I have many polygons in GRASS and want to color them according to their T-value. I can use v.colors and define a color table. That works fine when I plot the areas of the polygons. However, I would ...
0
votes
1answer
15 views

Overlaying of raster in GRASS for visualization?

I have generated insolation time rasters map in grass using r.sun module. How to overlay insolation time rasters over DSM depicting the color table for visualization?
1
vote
1answer
35 views

Export of group = multiband raster to another format not works in GRASS

I am really new in GRASS and my question is really basic but I dont realize where I am wrong. I have a set of single layers in my PERMANENT from some Landsat images (1 landsat = 7 one layer ...
1
vote
1answer
20 views

How to change GRASS language within QGIS?

I use GRASS plugin inside QGIS on Japanese version of windows 7 x64. As I start GRASS tools, all the content show in English but when I try to execute a tool, tools option dispalys in Japanese ...
0
votes
2answers
30 views

Export GRASS raster as GeoTiff : nodata values exported as -nan (what happens in R?)

I am using the package raster to work with GeoTiff raster files which I expoerted from GRASS using r.out.gdal. GRASS assigned the value -nan to some raster files (type FLOAT32) for missing values. ...
2
votes
1answer
46 views

Can QGIS or GRASS convert layer files to shapefiles?

Should I be downloading QGIS or GRASS? I want the program with the most features. Most importantly, I have a lot of .lyr files. Can either of these softwares convert to shp and if so, how can I do ...
0
votes
3answers
64 views

Discrete Waterpoints with Grass

I've been working with Grass GIS for about two months. I have to develop a method for the identification of target regions of small hydropower plants. Boundary conditions are a predetermined minimum ...
1
vote
0answers
8 views

GRASS GIS: Network analysis doesn't work correctly

I got a problem with the Network Analysis function v.net.iso in GRASS. I tried it so many times but the function doesn't work correctly. I tried to calculate isolines via the function v.net.iso, based ...
1
vote
0answers
17 views

Raster Mosaicking GRASS Issue

I have a project where I have to download DEMs from USGS and mosaic them. So I downloaded them from EarthExplorer and imported them into GRASS. When I start the GUI version of r.patch using the ...
0
votes
1answer
310 views

Can't launch GRASS GIS 6.4.3 GUI on windows 8.1

As title, I downloaded GRASS GIS from this website: GRASS GIS - Home, and I choose winGRASS 6.4.3 standalone installer to download. After I installed, I click on its icon: I can't launch it even ...
2
votes
1answer
96 views

GRASS GIS 7 in QGIS 2.6.1, Windows 7 64bit - Missing dependency

I am using QGIS Brighton 2.6.1. Today I have installed Grass GIS 7.0.0 RC2 to try its topology functions in QGIS. I have activated the provider, set the paths, but everytime I try to use any Grass ...
5
votes
0answers
58 views

Is it possible to generate a boustrophedon pattern which fill a vector Region with GRASS?

Every thing is in the title... I have a vector region in GRASS. And I would like to generate a vector (a polyline) beeing the bostrophedon pattern which fill this region. In the picture bellow, I ...
0
votes
1answer
185 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
0answers
128 views

Empty raster returned after GRASS i.atcorr with Landsat8 data

I've searched at length on previous forums but no solution seems to work for me. I'm trying to run the i.atcorr module on GRASS (version 6.4.3 on a Macbook Pro, Mavericks OSX) with Landsat8 imagery. ...
1
vote
2answers
470 views

LANDSAT 8 i.landsat.toar error GRASS 7

I am a bit new to GRASS, but I have managed to get a lot of good work done thus far. However, the following error is really throwing me off, because I can't find any help anywhere for it. I am using ...
0
votes
0answers
13 views

r.watershed outputs different depending on use of console and toolbox

I am returned two different outputs despite same input parameters from r.watershed depending on whether I run it from the console or from the GRASS toolbox. The threshold for both is 5000. They both ...
1
vote
0answers
10 views

r.water.outlet returning blank raster

I am trying to delineate a watershed using r.water.outlet. I have created a flow direction raster using r.watershed (threshold = 50) (cell size is 300m). I use this flow direction raster in ...
2
votes
3answers
375 views

Raster map in different zone () than region ()

I am new to QGIS (just installed QGIS 2.0.1) and am having problems running any spatial analysis tools. I followed the instructions on how to call GRASS tools into QGIS, but when I try to run the ...