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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1answer
36 views

QGIS - best fit to the sectoral terrain (SRTM 30m resolution data)

i need a help to find out the Slope of "best fit to the sectoral terrain". here is in details about the area of calculation. we have a reference point, from the reference point our sectoral area ...
5
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6answers
3k views

How to pansharpen LANDSAT 8 in GRASS?

Having used QGIS for quite some time for mapping, I was 'forced' to dig into GRASS as pansharpening is not directly executable in QGIS. After understanding more or less the structure, I did some ...
1
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0answers
37 views

GRASS gis: treating certain cells as starting points in mapcalc

I am attempting to calculate the vertical height from horizontal of every point on a slope. I want to use stream beds (the lowest points in my DEM) as my starting spot, with the horizontal plane ...
1
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1answer
51 views

Question about Using r.mapcalculator in Python console

According to the following conversation: Using r.mapcalculator in Python console? I tried: ##NoData Background=name ##RASTERLAYER_BAND=raster ##nodatabackground=output raster import processing ext ...
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1answer
203 views

Using r.mapcalculator in Python console?

I'm trying to use the r.mapcalculator algorithim in a python script, but I'm having problems in using the r.mapcalculator to tranform a raster layer with float values into integers. Using the ...
3
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1answer
69 views

GRASS r.reclass QGIS 2.14. error: “the following layers were not correctly generated”

I am getting a strange error message when running the GRASS r.reclass algorithm. The error states that: "The following layers were not correctly generated *reclassified You can check the ...
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0answers
34 views

n-dimensional visualization software

I am using Grass 7.04 standalone. I have made a 3d view of dem raster. How can I have a high resolution image file of it to work with photoshop? It seems that the only tool to have it is Nviz but it ...
1
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1answer
22 views

How to open .jp2 with GRASS 7.0.3

Does anyone know if I can use Grass to open a .jp2 image file? I am aiming to do some image classification on the image and when I try to import the image into the program a stream of errors comes up ...
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0answers
7 views

plotting a proportional sized snowfall fall pin ( also the numerical number) for 150 kal local ng positions on a us map

just starting to learn Grass. Need to learn how to have a usa outline map. (Is this spearfish?) On the map place pins ( for a given latitude and longitude) proportional in height for annual ...
3
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1answer
302 views

How do I open GRASS layers in QGIS

I'm quite a newbie to QGIS and GRASS.. I have installed QGIS 2.10.1 with GRASS 6.4.3 on my Windows 7 laptop and wish to open GRASS layers in QGIS. If I got it right, you can use the QGIS built-in ...
3
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1answer
119 views

QGIS GRASS raster to GeoTiff

First of all: Windows 8.1 QGIS 2.8.2 Wien I used the GRASS module r.watershed to delineate watersheds and get flows with a DEM. It worked fine so everything is OK so far. But now what I want to do ...
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0answers
20 views

Problem with i.landsat.acca on GRASS

I have a problem with my Landsat Tree Cover Continuous Field. The images are fully of clouds and shadows, so unreadable. The problem is the following: when I try to use i.landsat.acca to remove ...
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2answers
43 views

Error installing addons in GRASS 7.0.2: File is not a zip file?

When I attempt to install an addon in GRASS Setting->Install Extension from Addons and select the addon i want from the list (r.stream.order) i get the following error: "ERROR: File is not a zip file: ...
1
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0answers
66 views

Is this error “invalid context…fatal error” due to GRASS GIS bug or the system?

Copy of error message that appears in the terminal (Macbook Pro, OS X 10.9.5): MacBook-Pro.local Python[2653] :CGContextRestoreGState: invalid context 0x0. This is a serious error. This ...
0
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1answer
27 views

How to calculate stream order in GRASS 7.0.2?

I would like to calculate Strahler's and other stream hierarchy from my input raster but I am not sure how. This manual suggests tat I should use r.stream.order command, however in version 7.0.2 "...
2
votes
1answer
453 views

How to extract percentage of land cover from a raster according to multiple shapefiles?

I have a raster map that represents land cover of a region, and different shapefiles (total 120) in the same region. I want to know the percentage of every land cover for each shapefile. For example, ...
5
votes
2answers
1k views

How to properly open an ASTER data?

Yesterday i downloaded an Aster L1B image from USGS's website. If i load it in QGIS, it doesn't get displayed properly(location wise). Even after i've enabled "On the fly" option, it's not reading the ...
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0answers
16 views

GRASS 7.0.3 - Script to automate multiple simulations?

I am working in GRASS 7.0.3 and want to conduct a complex analysis of Least-Cost Paths of the many-to-many type. Specifically, I do have my elevation raster (ASTER DEM) and point data of 300 random ...
1
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1answer
74 views

Positive Topographic Openness - do any FOSS tools (other than SAGA) provide this?

I'm looking for a FOSS GIS tool to provide Positive Topographic Openness on 32-bit Ubuntu. (which rules out ArcGIS) Normally I use SAGA GIS for this, but my Ubuntu setup is a bit messed-up after a ...
0
votes
1answer
19 views

R.patch creating enormous file size

I'm using r.patch (within QGIS, GRASS 7) to patch two Float32 rasters both of which have a respective filesize of under 200MB. When I save the memory layer raster created by the r.patch function, the ...
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0answers
15 views

Grass Gis i.atcorr for Aerial data

Can Grass GIS i.atcorr module be customized for Aerial sensor? Attempted for Aerial sensor which has altitude of 13km. but module is failed .if the satellite altitude is changed to 100 km, module is ...
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0answers
24 views

Raster Precision QGIS

I am using r.patch extension in QGIS to join a number of LiDAR tiles, some of which overlap hence i am carrying out this task before utilising in a hydraulic model. R.Patch works fine, however the ...
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0answers
42 views

OS X Yosemite: copy / paste into shell GRASS 6.4.4. within QGIS 2.14.0

I want to know How to copy/paste into GRASS 6.4.4. shell within QGIS 2.14.0. I'm working with OS X Yosemite and the right mouse button doesn't work neither shortcut (cmd+c/cmd+v)
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2answers
30 views

How to export vector file in GrassGIS to QGIS

I am using GrassGIS to analyze watershed. I created a stream vector extracted from raster elevation data, how to extract the stream vector file so I can open it using QGIS?
2
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0answers
27 views

How do I merge a point attribute table to a polygon attribute table in QGIS or GRASS?

I have a point layer containing the following data: I want the following polygon areas to be added to the point attribute table as all the points occur inside the various features of the polygon ...
3
votes
1answer
71 views

GRASS r.in.lidar problem on Windows 10: 'no such file or directory'

I'm having problems to load .las files into Grass GIS 7.0.3 for Windows 10. I use the module r.in.lidar but I get the following message: What can I do? How can I solve the problem?
2
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2answers
236 views

QGIS 2.14.1 Processing Toolbox GRASS 7 .NVIZ Not working

I have a problem with the command GRASS 7 .nviz in QGIS 2.14.1 installed through QGIS-OSGeo4W-2.14.1-1-Setup-x86_64.exe.md5sum all GRASS commands work exept .nviz / nviz7 images: I test with ...
2
votes
2answers
152 views

Where is the nviz tool in qgis 2.14 with GRASS 7.0.3?

I hope Im not blind but I looked in the grass tools (modules) and qgis plugins but couldnt find it. When i try to run nviz from GRASS the whole programme chrashes just before concluding. Its a ...
1
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1answer
61 views

How to design a flood with water elevation on a specific point?

Actually I have to know the flooding area caused by a rise of the water level due to the implementation of a dam. So I would like to know if there is an extension or any tool in QGIS or GRASS which ...
4
votes
1answer
294 views

Cannot locate GRASS plugin in QGIS 2.14.1 on Linux

I am trying to load the GRASS plugin in QGIS but it is not shown in the plugin manager (no matter if I turn on experimental and deprecated plugins). Under processing / options / providers GRASS GIS 7 ...
1
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1answer
16 views

Grass GIS animation tool: zoom in to area of interest

The Grass GIS animation tool is great, but I'm struggling to be able to zoom into an area of the original rasters. Do I have to clip the rasters to achieve this, or can I use the advanced section of ...
5
votes
2answers
294 views

filling up a depression to create new surface

A collegue here has a problem I cannot help with. She has the surface (as raster) of a landslide release area (from AFTER the slide) and wants to calculate the calculate the theoretical/approximate ...
4
votes
2answers
5k views

Converting point grid to raster using GRASS?

If I load the original .csv file, I then have a map of the African continent represented by 14069 data points covering it at 40x40km resolution. Each data point shows solar radiation means across the ...
5
votes
2answers
121 views

GRASS r.in.lidar tool generates incomplete rasters

I have been trying to import a huge LIDAR file (10.5) Gb to GRASS GIS using r.in.lidar. It does the task, but only for part of the image, as shown below: Canopy Height Model (CHM) generated with ...
1
vote
1answer
20 views

Matching Python and GRASS projection

I have a colleague producing maps with the following Python Basemap projection: from mpl_toolkits.basemap import Basemap m = Basemap(width=6000000,height=3900000, resolution='l',projection='...
2
votes
1answer
116 views

Cost Distance Map in QGIS

My question is very similar to Cost Distance Analyst In QGIS? However, I'm looking for a means by which I can create a raster displaying the cumulative cost of each pixel to a specified destination ...
1
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2answers
29 views

Issue running r.region in GRASS command line

I'm currently attempting to use r.region to preform analysis on a specific area of a raster image. I'm receiving Lat/Long data from the step before me, but I'm having issues use that data in r.region....
1
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1answer
22 views

To display custom data on a Shape file

I have a shape file which is a district map. There are close to 800 districts. There are around 30 funding agencies. There are 4 different health programs. The different funding agencies fund specific ...
1
vote
2answers
792 views

How to create a time series with a NetCDF raster from Ensembles E-OBS using GDAL, R, GRASS GIS or SAGA GIS

I downloaded a NetCDF file that contains daily precipitation values from 1-1-1950 to 30-6-2013. The raster has 23191 bands. http://eca.knmi.nl/download/ensembles/download.php My goal is to analyze ...
3
votes
1answer
36 views

Is it possible to start the GRASS GUI from R?

I am using the rgrass7 package in R in order to work with GRASS GIS. After having set the needed enviornment variables, I can now launch a GRASS session from R and and work on my GRASS data using ...
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2answers
27 views

What does the max_slope_length option do in GRASS r.watershed?

What does the max_slope_length option do to the r.watershed program in grass? According to the manual, it should limit the length of a stream. Does this mean a max_slope_length equal to the raster ...
0
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0answers
30 views

Problems with QGIS 2.14.1 and GRASS 7.0.3 [duplicate]

I been having problems with modules GRASS / GRASS 7.0.3 in QGIS 2.14.1 I did the installation with Standalone Installer QGIS Version 2.14 (64bit) QGIS-OSGeo4W-2.14.1-1-Setup-x86_64.exe My OS: ...
2
votes
0answers
80 views

Grass processing not configured in OSGEO4w QGIS 2.14.1

I get the below error when I try to use grass processing from within QGIS. The error is given on all commands and I have got this error on 2 machines. I am using windows. "This algorithm cannot ...
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vote
1answer
252 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 ...
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0answers
22 views

Process road polylines to not overlap building polygons

Is anyone aware of a processing tool in Grass or similar which will find segments of polylines which overlap polygons in another dataset and reroute the polyline to avoid the collision? My problem is ...
8
votes
3answers
160 views

Why are the holes in my polygons not generalized?

I have one polygon layer with many holes. I would like to generalize it. I used v.generalize of grass. With it, I used chaiken algorithm. But, only the borders of polygons were generalized, the holes ...
3
votes
1answer
74 views

Convert xyz points to topography and calculate mean slope

I am working on point data (x, y, z) in meters from origin. I have between 24 and 35 points for each plot (10mx10m), with random locations. I would like to modelise topography over the whole plot in ...
2
votes
1answer
56 views

command r.stream.order not found in grass 7.0.3 how to install r.stream module?

I have installed QGIS 2.14.1 and GrassGIS 7.0.3 I found in OSGEO Grass wiki page a command that calculate Strahler's and Horton's stream order Hack's main streams and Shreeve's stream magnitude from ...
4
votes
3answers
3k views

How to calculate LS Factor of Watershed for RUSLE Calculation?

I managed to get subbasins for my catchment (7 km^2) with their areas but I haven't figured out how to get the LS factor (see Revised Universal Soil Loss Equation) from it. I have the vector file ...
3
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0answers
13 views

What does the blocking option do in GRASS r.watershed?

What does the blocking option do to the r.watershed program in grass? According to the manual, it should stop water from being routed past that location, but it appears to have no effect. I'm trying ...