[GRASS-user] areas with islands and v.generalize

Hi everyone, i'm trying to use v.generalize to smoothen polygon areas generated by r.to.vect. when using v.generalize in=cold out=cold_smooth method=douglas type=area thresh=0.1 the result remains the same as the input geometry. Leaving out type=area leads to smoothened results though islands

Re: [GRASS-user] areas with islands and v.generalize

Am 09.09.2011 15:04, schrieb Hamish: Georg wrote: i'm trying to use v.generalize to smoothen polygon areas generated by r.to.vect. when using v.generalize in=cold out=cold_smooth method=douglas type=area thresh=0.1 the result remains the same as the input geometry. try running

[GRASS-user] Re: areas with islands and v.generalize

Am 09.09.2011 15:44, schrieb Georg Kaspar: no difference. though i noticed that v.generalize does not get stuck a 62% when using the snakes algorithm - it just takes a long time to run. The result is nearly perfect though islands are still converted to polygons... problem solved by running

[GRASS-user] Re: v.proj

Am 09.09.2011 14:48, schrieb adm: I want to use v.proj to reproject vector files from another location. you need to specify the location of origin: v.proj in=file location=locationA mapset=name_of_mapset_in_locationA out=file best regards, Georg

[GRASS-user] Re: areas with islands and v.generalize

Am 09.09.2011 16:06, schrieb Georg Kaspar: problem solved by running v.extrude -d on the results. An by that i mean v.extract... sorry ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user

[GRASS-user] PyWPS and GRASS - Example?

Hi everyone, i'm looking for an examplary PyWPS process that makes use of GRASS GIS. So far I found a lot of tutorials concerning the setup of PyWPS but what I need is a working process - if possible with a fitting OpenLayers (or similar) frontend. Can anybody help me out? Thanks in advance,

Re: [GRASS-user] SMAP algorithm

Nikos wrote: Hi Georg. Did you find any (useful) material with respect to (i.)SMAP? Regards, Nikos I'm afraid no. You'll have to stick with the papers mentioned on the GRASS manual page - good luck! best regards, Georg ___ grass-user mailing list

[GRASS-user] Re: algorithm used in i.cluster

Markus Neteler wrote: Luckily it is open source :) and also quite well documented (at least it is possible to understand what's going on without being a C-guru) does anybody know which exact algorithm is used (k-means probably...)? I'm afraid that you need to compare it to a k-means

[GRASS-user] Re: algorithm used in i.cluster

Sorry for flooding the list, but i found an interesting note in Schowengerdt (2007), p. 400: The ISODATA algorithm (Ball and Hall, 1967) is a common modification of the K-means algorithm and includes merging of clusters if their separation is below a threshold, and splitting of a single

[GRASS-user] algorithm used in i.cluster

hi, a quote from Markus' Introduction to GRASS GIS Software (1998): [...] GRASS uses the minimum distance to means algorithm for deriving the clusters [...] minimum distance to means is described in Lillesand and Kiefer (2000), as a supervised classification technique which requires a

[GRASS-user] Pansharpening using PCA in R

Hi, I'm trying to apply pansharpening to a set of 4 quickbird channels by exchanging the first principal component with the panchromatic channel. Since an inverse PCA is not possible using GRASS (alone) I used the following workflow: R: 1. import data into R using spgrass6 2. eliminate NAs

Re: [GRASS-user] i.rgb.his/i.his.rgb not working properly

Markus Neteler wrote: On Tue, Sep 29, 2009 at 3:26 PM, Georg Kaspar ge...@muenster.de wrote: [1] d.rgb r=szene1_mul.4 g=szene1_mul.3 b=szene1_mul.2 -- http://img96.imageshack.us/img96/9487/screen1i.png are you sure about the channel order? yes, it's a false color composite. i set

[GRASS-user] Re: i.rgb.his/i.his.rgb not working properly

Georg Kaspar wrote: i converted the results back to rgb and it works. pansharpening was also possible using channel 8. unfortunately - it still doesn't work using quickbird data It work's, though i had to rescale all channels to 8bit using r.mapcalc. Is it possible that 16bit

[GRASS-user] i.rgb.his/i.his.rgb not working properly

Hi, I'm having some problems using i.rgb.his/i.his.rgb to convert quickbird data from RGB to IHS and vice versa (original purpose was pan sharpening). The results look totally weird and I don't know why. Here is a protocol along with some screenshots: [1] d.rgb r=szene1_mul.4 g=szene1_mul.3

Re: [GRASS-user] i.rgb.his/i.his.rgb not working properly

Hamish wrote: try setting all maps with r.colors color=grey255 still the same. i also rescaled the data using r.rescale.eq and r.mapcalc but to no gain. ___ grass-user mailing list grass-user@lists.osgeo.org

[GRASS-user] Re: Problems with HIS conversion

Georg Kaspar schrieb: ok, I just found out that the data is stored using more than 1 byte: r.info -r szene1_mul.1 min=0 max=2047 how can I convert it to a range of [0,255]? r.mapcalc szene1_mul_1byte.1 = 255*(szene1_mul.1/2047) would that be appropriate? I'll give it a shot ;) ok

[GRASS-user] extracting probabilities from i.maxlik

Hi, as mentioned before, I need to extract probability-values from i.maxlik that are computed for each pixel for each class. Is there an 'easy' way to achieve this? If I need to dig into the source code, can anybody help me to find the right line in the right class? I'm not that much of a C

[GRASS-user] probabilistic label relaxation

Hi there, I'm planning to implement probabilistic label relaxation for grass as part of my diploma thesis. To achive this, I need to know if I can extract probability values from modules like i.maxlik. Since its output is generated from a set of probabilities for each pixel, describing the

[GRASS-user] shortest / less steep path in DEM

Hi, to calculate the shortest path from a mountain top into the valley, I ususally use r.flow, but what if I do not want the shortest but the less steepest path? thanks, Georg ___ grass-user mailing list grass-user@lists.osgeo.org

[GRASS-user] Re: shortest / less steep path in DEM

On Tue, 17 Feb 2009 13:39:15 +, Georg Kaspar wrote: Hi, to calculate the shortest path from a mountain top into the valley, I ususally use r.flow [...] sorry, I meant r.drain... ___ grass-user mailing list grass-user@lists.osgeo.org http

[GRASS-user] Re: Python scripting

On Fri, 13 Feb 2009 14:14:47 +, Glynn Clements wrote: It's part of the GRASS source code: lib/python/grass.py. It should get installed into $GISBASE/etc/python during the build process, and Init.sh should add that directory to PYTHONPATH. Also, it's only present in 6.4, 6.5 and 7.0, not

[GRASS-user] Python scripting

Hi, I'm sorry but I just can't find the python grass module anywhere on the internet. Where can I get it from? Everytime I triy to run a python script I get ImportError: No module named grass. thanks, Georg ___ grass-user mailing list

[GRASS-user] Re: 6.4 installation on ubuntu

On Tue, 03 Feb 2009 12:21:49 +0100 Markus Neteler wrote: I guess it is called grass64 Does this help? Markus yes, helps :) I also had to change permissions to 755 and now it's working! thanks! ___ grass-user mailing list

[GRASS-user] 6.4 installation on ubuntu

Hi, today I succesfully compiled GRASS 6.4 with PostgreSQL support. After that I created a deb-file using checkinstall. Now, after installing the deb file I cannot run grass anymore. This is the message I receive: The program 'grass' is currently not installed. You can install it by typing:

[GRASS-user] Re: understanding r.watershed

If these lakes have an outflow, i.e. water is leaving these lakes, the results will be more realistic when you omit the depression input to r.watershed and only use the (not filled) DEM. If you are talking about the basins output having NULL values around these depression, this is because

[GRASS-user] Re: understanding r.watershed

On Mon, 02 Feb 2009 19:31:06 +0100 Markus Metz wrote: Generally there is no need to purge the input DEM from depressions, why do you insist on doing so? The difference between purging a DEM and providing an option depression=map with real depressions has been explained before in this thread