Hot answers tagged grass
8
GRASS is usually used for scientific purposes. So unless you want to do some sophisticated spatial analysis or routine, just stick with QGIS. Also GRASS works with its own formats so you will have to import/export data to exchange data with someone. Even if you will need sophisticated spatial analysis or routine at some point you will be able to do it with ...
3
In the master version, the Sextante plugin is integrated into the application/bundle and may conflict with older versions installed in the .qgis folder.
There are daily versions, not stable by definition, which have errors that, often, are resolved in the next version, or not, and you have installed one of these versions .
One of the objectives of these ...
2
GRASS is written in C and have a ctypes python lib and recently an improved high level python library called pygrass. see pygrass documentation here. To work with raster data please refer to raster section of pygrass.
I would suggest you to start with python than using shell programming because all shell scripts are ported to python for cross-platform ...
2
What do you use to extract contours from LiDAR data? Every how many meters are your contours?
If you start from a raster derived from the LiDAR data you could try to run a smoothing filter over the raster and then extract the contours: dangles and islands derive from sudden changes in heights (e.g.. sometimes outliers).
PS I know that running a smoothing ...
2
My favorite saying from one of my professors is, "Garbage in, Garbage Out." No matter the algorithm or method used, there will be no "magic button" that will fix a crummy dataset. Sometimes, the tools will make the data less accurate. No errors, but incorrect.
Each project you will work on will have different requirements. I don't feel a quick map made ...
1
The GRASS tutorial looks like the ticket. Following along your steps, are you converting the contours to raster somewhere between 1 and 4?
Last paragraph in the About section:
A number of the r.surf.* modules want the input data to be in raster
form already, so we rasterize the contour lines, using the level
column for the height values. Also some ...
1
Isn't it obvious that you need to install SAGA first? If SAGA is installed check in SEXTANTE settings if it is activated. Install python-saga module. Also check out this post on setup SEXTANTE for Ubuntu.
If none of this helps the reason may be that SEXTANTE is looking for SAGA modules in the wrong directory. The default path to SAGA algorithms is ...
1
Thank you for your reply and helpful information. I was actually able to track down the missing Python modules (importlib and psycopg2), and install them. The importlib module was available from here:
https://pypi.python.org/pypi/importlib
After downloading the module, it was simply a matter of running the setup.py file with the following command: ...
1
While I suspect a simple error in the setting of the Computational region, you can use r.univar to check the univariate statistic of each raster map in order to identify the map which causes the problems. With r.univar you'll see if any NULL data layer is present.
1
The proper way to set the -q flag in a GRASS-Python script inside a grass.run_command() is quiet = True. In the example given in the question (for grass64), that would be:
grass.run_command("r.stats", flags='l', input=<file>, output=<*.csv file>, fs=',', quiet = True)
Read also the GRASS-Wiki page GRASS_Python_Scripting_Library for examples.
1
Your question is poorly stated. It as at once general, as it asks if anyone has ideas about how to implement MFDs, and specific, as it seems to ask what is wrong with you code. I'll try to answer this second conceptualization of your question here.
You claim that the code you've posted is not optimized. I have rewritten the code below as I think you should ...
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