Multiple v.net.path parameters
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In reply to this post
by J. Holden
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In reply to this post
by J. Holden
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In reply to this post
by Daniel Bundala
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..with attachment
Hello Daniel (and others), I ran the module successfully, but only with a network, where every line ends with the next node. In attached example it is possible to calc path from 1 to 4 and from 5 to 6, but not from 1 to 2,3,5,6 or from 5 to anywhere expect 6 and so on. Do you have an idea how to handle this? Especially: do you know if "breaking the lines" (eg. dark green one at point 5) is possible with networking techniques? Sorry for asking you directly, but I hopefully thought you are deep inside the topic at the moment. Thanks anyway for your work! Achim Daniel Bundala schrieb > > Hello all, > > > > I have finished v.net.distance module as a part of my Google Summer of > > Code project. The (source code of) module can be downloaded from grass > > add-ons repository (vector/net.analyze). I recommend to download the > > entire directory to avoid any compilation issues. Additionally, you > > get an access to some latest network analysis modules! Anyway, simple > > make command in the net.analyze directory should compile the modules > > (and library). There is no documentation (yet), however, the interface > > should be similar to the one used in v.net.path and/or v.distance. > > Finally, here is a couple of nice pictures: > > > > http://people.ksp.sk/~dano/grass/nd.png > > http://people.ksp.sk/~dano/grass/ndt.png > > http://people.ksp.sk/~dano/grass/ndtd.png > > > > Blue and orange lines show the shortest length and time paths > > > > Best, > > Daniel > > > > On Wed, Jul 1, 2009 at 5:56 PM, Moritz > > Lennert<[hidden email]> wrote: >> >> On 01/07/09 04:44, J. Holden wrote: >>> >>> Hello, >>> >>> >>> >>> I am looking to use v.net.path to determine the distance of many >>> >>> different points to many different other points on a network. >>> >>> >>> >>> Is it possible to send multiple parameters to v.net.path? For >>> >>> instance, I have (in theory) 4 points connected to a network. I want >>> >>> to find the distance of the line segments between points 1 and 4, 2 >>> >>> and 4, & 3 and 4. >>> >>> >>> >>> I want to: run v.net.path once by passing multiple parameters; get >>> >>> vector line output of each of these three paths found by v.net.path >>> >>> in one output file; calculate the distance of each line from the >>> >>> using v.to.db. >>> >>> >>> >>> Since this is not a module of GRASS which I have worked with in the >>> >>> past, I am wondering if this is possible. >> >> Sure, as mentioned on the man page: >> >> >> >> "Nodes can be piped into the program from file or from stdin. The >> >> as follows: >> >> >> >> id start_point_category end_point_category >> >> >> >> or >> >> >> >> id start_point_x start_point_y end_point_x end_point_y" >> >> >> >> >> >> So to take your example, and assuming that 1,2,3,4 are category >> >> existing points: >> >> >> >> Create a file containing: >> >> >> >> 1 1 4 >> >> 2 2 4 >> >> 3 3 4 >> >> >> >> and feed it to v.net.path with the file= parameter. >> >> >> >> You will then get one vector map with severals lines which have >> >> values used in the first column of your file. >> >> >> >> Moritz >> >> _______________________________________________ >> >> grass-user mailing list >> >> [hidden email] >> >> http://lists.osgeo.org/mailman/listinfo/grass-user >> >> > > _______________________________________________ > > grass-user mailing list > > [hidden email] > > http://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [hidden email] http://lists.osgeo.org/mailman/listinfo/grass-user |
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In reply to this post
by achim
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Hello Daniel,
thanks you very much for helping. > If I understand your description and image correctly, then the line > from 1 to 4 is one single line and nodes 2 and 3 lie on it. If this is You understand me right. I thought, you maybe knew a way, doing the breaking of the lines at the "on line laying" points. I thought its there is a way like "automatically(!) adding a little road to a big one from one side (not crossing) and integrating it to the network"? Greetings, Achim PS: The bug is in the v.edit tool=break, as I mentioned before: breaking one selected line on a desired coordinate works well, but selecting two or more (or all) (eg. yellow and red, point 2) breaking on the same point, I get artifacts. This depends on the direction of the yellow line. (like http://lists.osgeo.org/pipermail/grass-user/attachments/20090814/816f9568/break-0001.jpg) If you have an idea..its welcome! Not being in touch with the structure of the program, sadly I am not capable of fixing the bug in acceptable time, Daniel Bundala schrieb: > the case then the module does not find a path from, say, 1 to 5. The > reason is, as you mentioned in your email, that "the module runs > successfully, but only with a network, where every line ends with the > next node" and the module "ignores" intermediate nodes. I did not test > it, but I think you get the same behaviour with v.net.path as well. In > general, this is not a bug. The thing is that the line lengths/costs > are read from a table and may represent anything and so if you know > that the cost of traversing from 1 to 4 is X then this does not tell > you what the cost of traversing from 1 to 2 or 2-3 should be. So to > fix it, you need to break the lines that is, to break line 1-4 to > lines 1-2, 2-3, 3-4. > > Hope this helps, > Daniel > > On Mon, Aug 17, 2009 at 3:07 PM, achim<[hidden email]> wrote: >> Hello Daniel (and others), >> >> I ran the module successfully, but only with a network, where every line >> ends with the next node. >> >> In attached example it is possible to calc path from 1 to 4 and from 5 >> to 6, but not from 1 to 2,3,5,6 or from 5 to anywhere expect 6 and so on. >> >> Do you have an idea how to handle this? >> >> Especially: do you know if "breaking the lines" (eg. dark green one at >> point 5) is possible with networking techniques? >> >> Sorry for asking you directly, but I hopefully thought you are deep >> inside the topic at the moment. >> >> Thanks anyway for your work! >> Achim >> >> >> >> Daniel Bundala schrieb >> >>> Hello all, >>> >>> I have finished v.net.distance module as a part of my Google Summer of >>> Code project. The (source code of) module can be downloaded from grass >>> add-ons repository (vector/net.analyze). I recommend to download the >>> entire directory to avoid any compilation issues. Additionally, you >>> get an access to some latest network analysis modules! Anyway, simple >>> make command in the net.analyze directory should compile the modules >>> (and library). There is no documentation (yet), however, the interface >>> should be similar to the one used in v.net.path and/or v.distance. >>> Finally, here is a couple of nice pictures: >>> >>> http://people.ksp.sk/~dano/grass/nd.png >>> http://people.ksp.sk/~dano/grass/ndt.png >>> http://people.ksp.sk/~dano/grass/ndtd.png >>> >>> Blue and orange lines show the shortest length and time paths respectively. >>> >>> Best, >>> Daniel >>> >>> On Wed, Jul 1, 2009 at 5:56 PM, Moritz >>> Lennert<[hidden email]> wrote: >>>> On 01/07/09 04:44, J. Holden wrote: >>>>> Hello, >>>>> >>>>> I am looking to use v.net.path to determine the distance of many >>>>> different points to many different other points on a network. >>>>> >>>>> Is it possible to send multiple parameters to v.net.path? For >>>>> instance, I have (in theory) 4 points connected to a network. I want >>>>> to find the distance of the line segments between points 1 and 4, 2 >>>>> and 4, & 3 and 4. >>>>> >>>>> I want to: run v.net.path once by passing multiple parameters; get >>>>> vector line output of each of these three paths found by v.net.path >>>>> in one output file; calculate the distance of each line from the file >>>>> using v.to.db. >>>>> >>>>> Since this is not a module of GRASS which I have worked with in the >>>>> past, I am wondering if this is possible. >>>> Sure, as mentioned on the man page: >>>> >>>> "Nodes can be piped into the program from file or from stdin. The syntax is >>>> as follows: >>>> >>>> id start_point_category end_point_category >>>> >>>> or >>>> >>>> id start_point_x start_point_y end_point_x end_point_y" >>>> >>>> >>>> So to take your example, and assuming that 1,2,3,4 are category values of >>>> existing points: >>>> >>>> Create a file containing: >>>> >>>> 1 1 4 >>>> 2 2 4 >>>> 3 3 4 >>>> >>>> and feed it to v.net.path with the file= parameter. >>>> >>>> You will then get one vector map with severals lines which have the category >>>> values used in the first column of your file. >>>> >>>> Moritz >>>> _______________________________________________ >>>> grass-user mailing list >>>> [hidden email] >>>> http://lists.osgeo.org/mailman/listinfo/grass-user >>>> >>> _______________________________________________ >>> grass-user mailing list >>> [hidden email] >>> http://lists.osgeo.org/mailman/listinfo/grass-user _______________________________________________ grass-user mailing list [hidden email] http://lists.osgeo.org/mailman/listinfo/grass-user |
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