Re: [GRASS-user] v.distance and optimizations
On 03/11/17 14:45, Eric Patton wrote: Hi, I am running v.distance on a massive point vector which represents coastline vertices, uploading the attributes of another point vector, in this case, the vectorized point version of a DEM slope raster. While the program is working as expected, (I have seen the output on smaller files, and it looks correct), it is extremely slow because the ‘from’ vector has ~ 700k points in it, and my search radius is 200 m for each point. I checked htop and v.distance is only using one CPU. The process has been running for about a week, and is at 69%. It would be interesting to find out if this is due to the actual distance algorithm, or more to database access. You might want to try using the -p flag and redirect the output to a file just to see if this is faster. I was wondering if there were any way to make v.distance use more than one CPU (I have four)? Or perhaps there is an environment variable I’m not aware of? AFAIK there is no parallelization in v.distance. Moritz ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.distance and optimizations
Hi, I am running v.distance on a massive point vector which represents coastline vertices, uploading the attributes of another point vector, in this case, the vectorized point version of a DEM slope raster. While the program is working as expected, (I have seen the output on smaller files, and it looks correct), it is extremely slow because the ‘from’ vector has ~ 700k points in it, and my search radius is 200 m for each point. I checked htop and v.distance is only using one CPU. The process has been running for about a week, and is at 69%. I was wondering if there were any way to make v.distance use more than one CPU (I have four)? Or perhaps there is an environment variable I’m not aware of? ~ Eric. ___ grass-user mailing list grass-user@lists.osgeo.org https://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance -a : how join output table to output lines?
On 08/10/13 13:52, Enrico Gallo wrote: Dear Micha, dear list, 2013/10/3 Micha Silver On 03/10/2013 12:42, Enrico Gallo wrote: Dear list, when using (GRASS 6.4.3) v.distance -a , points to lines, you get: 1. [output] vector theme, with no attribute table, with N elements 2. [table] , with N rows, optionally with source and target cat Any idea about joining the two outputs without spatial join? You probably want to look at the "upload=..." parameter the problem is a bit more complex than using the "upload" parameter, IMHO when using v.distance looking for all possible connections (not only the nearest one) v.distance -a from=vector_from to=vector_to output=connector upload=cat,dist column=cat_to,distance table=connector_attributes we get - a vector output with connecting lines - an output table with from_cat [by default], cat_to& distance fields, completely populated the output table seems to me a perfect attribute table for vector output, but no common field is given to join the two: Adding a table (v.db.addtable) and updating the cat field (v.to.db, cat) of vector output doesn't solve, as I am not able to add an autoincrement field in output table to perfom a join, without direct SQL tricks. Connecting the given output table (v.db.addtable) and then updating a cat field, doesn't help even, because v.to.db uses an "INSERT" statement with cat option , not the usual "UPDATE", so you have N records with no cat + N records with cat but without attributes. In both cases we are assuming the two "outputs" have the same order for elements , but I don't know how much robust is this assumption! But without a robust join, any spatial analysis of connecting lines is almost impossible... I am missing something trivial to bypass this impasse? No, what you are trying to do seems quite obvious, but is not implemented in v.distance AFAIK. I think you should file an enhancement request. I agree that being able to link the table resulting from -a to the vector map would be a nice addition. Moritz ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance -a : how join output table to output lines?
Dear Micha, dear list, 2013/10/3 Micha Silver > > On 03/10/2013 12:42, Enrico Gallo wrote: > > Dear list, > > when using (GRASS 6.4.3) v.distance -a , points to lines, you get: > 1. [output] vector theme, with no attribute table, with N elements > 2. [table] , with N rows, optionally with source and target cat > > Any idea about joining the two outputs without spatial join? > > You probably want to look at the "upload=..." parameter the problem is a bit more complex than using the "upload" parameter, IMHO when using v.distance looking for all possible connections (not only the nearest one) v.distance -a from=vector_from to=vector_to output=connector upload=cat,dist column=cat_to,distance table=connector_attributes we get - a vector output with connecting lines - an output table with from_cat [by default], cat_to & distance fields, completely populated the output table seems to me a perfect attribute table for vector output, but no common field is given to join the two: Adding a table (v.db.addtable) and updating the cat field (v.to.db, cat) of vector output doesn't solve, as I am not able to add an autoincrement field in output table to perfom a join, without direct SQL tricks. Connecting the given output table (v.db.addtable) and then updating a cat field, doesn't help even, because v.to.db uses an "INSERT" statement with cat option , not the usual "UPDATE", so you have N records with no cat + N records with cat but without attributes. In both cases we are assuming the two "outputs" have the same order for elements , but I don't know how much robust is this assumption! But without a robust join, any spatial analysis of connecting lines is almost impossible... I am missing something trivial to bypass this impasse? Regards, Enrico ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance -a : how join output table to output lines?
On 03/10/2013 12:42, Enrico Gallo wrote: Dear list, when using (GRASS 6.4.3) v.distance -a , points to lines, you get: 1. [output] vector theme, with no attribute table, with N elements 2. [table] , with N rows, optionally with source and target cat Any idea about joining the two outputs without spatial join? You probably want to look at the "upload=..." parameter Many thanks Enrico Gallo This mail was received via Mail-SeCure System. ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user This mail was received via Mail-SeCure System. -- Micha Silver GIS Consulting 052-3665918 http://www.surfaces.co.il ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.distance -a : how join output table to output lines?
Dear list, when using (GRASS 6.4.3) v.distance -a , points to lines, you get: 1. [output] vector theme, with no attribute table, with N elements 2. [table] , with N rows, optionally with source and target cat Any idea about joining the two outputs without spatial join? Many thanks Enrico Gallo ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance anything to anything
On 16/10/12 10:02, Markus Metz wrote: On Tue, Oct 16, 2012 at 12:52 AM, Moritz Lennert wrote: On 15/10/12 16:30, Markus Metz wrote: So how does it calculate the distance between two lines (lines or boundaries) ? Between closest vertices ? What about lines that cross several other lines, or lines that cross each other at several points ? For lines to lines, say line A to line B, it calculates shortest distance of each vertex in A with each segment (not vertex) in B. So far, this is the same like in the original version, results are identical. The original version did not have line to line... What I meant was that this is equivalent to the shortest distance of several points to a line, regarding points as line vertices. Ok. Much better, thanks ! Just one issue still with the area2area case for the test polygon with cat=2: http://164.15.12.207/grass/v_distance_areas2.png The connection line/point doesn't touch the the polygon in the from map. But it is inside the polygon of the 'from' map. In this implementation, any shared location is as good as any other. Calculating an intersection is costlier than to check if a vertex is inside a polygon. The vertex of the boundary of the 'to' area is inside the 'from' area, thus a common location. For speed reasons, the distance is set to zero and no further tests are done. Ok, this makes it clear. Thanks ! The results can be unexpected for 'to' areas with isles, because v.distance (in all versions) does not require a 'to' feature to have a category, which also means that isles inside areas which themselves can be areas without centroids are regarded as valid 'to' features, just without category. But even though the results can be unexpected, I would leave them as such, otherwise 'to' feature would need to have a category, potentially leading to also different results for points to lines which has always been supported. Yes, that's why documentation is so important on all this. Moritz ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance anything to anything
On Tue, Oct 16, 2012 at 12:52 AM, Moritz Lennert wrote: > On 15/10/12 16:30, Markus Metz wrote: > >>> So how does it calculate the distance between two lines (lines or >>> boundaries) ? Between closest vertices ? What about lines that cross >>> several >>> other lines, or lines that cross each other at several points ? >> >> >> For lines to lines, say line A to line B, it calculates shortest >> distance of each vertex in A with each segment (not vertex) in B. So >> far, this is the same like in the original version, results are >> identical. > > > The original version did not have line to line... What I meant was that this is equivalent to the shortest distance of several points to a line, regarding points as line vertices. > > >>> >>> In GRASS 6, v.distance can calculate distances only from point,centroid to point,line,boundary,centroid,area. >>> >>> >>> >>> AFAIK, this was due to the conceptual issue mentioned above. I think that >>> the answer has to be clearly explained in the manual because they are not >>> as >>> straightforward. And a first rapid test shows that these issues seem to >>> be >>> problematic in your implementation: >>> >>> http://164.15.12.207/grass/v_distance_lines.png >>> http://164.15.12.207/grass/v_distance_areas.png >>> >>> red: from features (quickly digitized test data available here: >>> http://164.15.12.207/grass/v_distance_testdata.tgz) >>> black: to features (roadsmajor and urbanarea from nc_spm_08) >>> green: connecting lines between from and to feature >> >> >> Thanks for testing! These issues should be fixed, at least conforming >> to my explanation above, in r53401. > > > Much better, thanks ! Just one issue still with the area2area case for the > test polygon with cat=2: > > http://164.15.12.207/grass/v_distance_areas2.png > > The connection line/point doesn't touch the the polygon in the from map. But it is inside the polygon of the 'from' map. In this implementation, any shared location is as good as any other. Calculating an intersection is costlier than to check if a vertex is inside a polygon. The vertex of the boundary of the 'to' area is inside the 'from' area, thus a common location. For speed reasons, the distance is set to zero and no further tests are done. The results can be unexpected for 'to' areas with isles, because v.distance (in all versions) does not require a 'to' feature to have a category, which also means that isles inside areas which themselves can be areas without centroids are regarded as valid 'to' features, just without category. But even though the results can be unexpected, I would leave them as such, otherwise 'to' feature would need to have a category, potentially leading to also different results for points to lines which has always been supported. Markus M ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance anything to anything
On 15/10/12 16:30, Markus Metz wrote: So how does it calculate the distance between two lines (lines or boundaries) ? Between closest vertices ? What about lines that cross several other lines, or lines that cross each other at several points ? For lines to lines, say line A to line B, it calculates shortest distance of each vertex in A with each segment (not vertex) in B. So far, this is the same like in the original version, results are identical. The original version did not have line to line... Now if line A is a line or boundary, it calculates the shortest distance of each vertex in B to each segment in A. Additionally, it checks for intersections. In case of intersections, the first intersection found is used and the distance set to zero. For lines to areas, it behaves similar to the original version. If a line is inside an area, the distance is set to zero. The first point of the line inside the area is used as common point. The distance is also set to zero if the line intersects with the outer ring or any of the inner rings (isles), in which case the fist intersection is used as common point. For areas to areas, the module checks first for overlap or if one area is (partially) inside the other area. This is computationally quite intensive. If the outer rings of the two areas do not overlap, the distance is calculated as above for lines to lines, treating the outer rings as two lines. Again, the first point encountered falling into an area is used as common point, or the first intersection point. For anything else than points to lines, there can be several common points with distance = zero, and the closest location could then be several points or several lines or several areas (result of overlay). For v.distance, I choose to select a single point, and not create an overlay like v.overlay. Thanks. I think this should go into the man page. In GRASS 6, v.distance can calculate distances only from point,centroid to point,line,boundary,centroid,area. AFAIK, this was due to the conceptual issue mentioned above. I think that the answer has to be clearly explained in the manual because they are not as straightforward. And a first rapid test shows that these issues seem to be problematic in your implementation: http://164.15.12.207/grass/v_distance_lines.png http://164.15.12.207/grass/v_distance_areas.png red: from features (quickly digitized test data available here: http://164.15.12.207/grass/v_distance_testdata.tgz) black: to features (roadsmajor and urbanarea from nc_spm_08) green: connecting lines between from and to feature Thanks for testing! These issues should be fixed, at least conforming to my explanation above, in r53401. Much better, thanks ! Just one issue still with the area2area case for the test polygon with cat=2: http://164.15.12.207/grass/v_distance_areas2.png The connection line/point doesn't touch the the polygon in the from map. Moritz ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance anything to anything
On Mon, Oct 15, 2012 at 3:09 PM, Moritz Lennert wrote: > On 13/10/12 15:51, Markus Metz wrote: >> >> In GRASS7, v.distance can now calculate distances from >> point,line,boundary,centroid,area to >> point,line,boundary,centroid,area. > > > So how does it calculate the distance between two lines (lines or > boundaries) ? Between closest vertices ? What about lines that cross several > other lines, or lines that cross each other at several points ? For lines to lines, say line A to line B, it calculates shortest distance of each vertex in A with each segment (not vertex) in B. So far, this is the same like in the original version, results are identical. Now if line A is a line or boundary, it calculates the shortest distance of each vertex in B to each segment in A. Additionally, it checks for intersections. In case of intersections, the first intersection found is used and the distance set to zero. For lines to areas, it behaves similar to the original version. If a line is inside an area, the distance is set to zero. The first point of the line inside the area is used as common point. The distance is also set to zero if the line intersects with the outer ring or any of the inner rings (isles), in which case the fist intersection is used as common point. For areas to areas, the module checks first for overlap or if one area is (partially) inside the other area. This is computationally quite intensive. If the outer rings of the two areas do not overlap, the distance is calculated as above for lines to lines, treating the outer rings as two lines. Again, the first point encountered falling into an area is used as common point, or the first intersection point. For anything else than points to lines, there can be several common points with distance = zero, and the closest location could then be several points or several lines or several areas (result of overlay). For v.distance, I choose to select a single point, and not create an overlay like v.overlay. > > >> In GRASS 6, v.distance can calculate distances only from >> point,centroid to point,line,boundary,centroid,area. > > > AFAIK, this was due to the conceptual issue mentioned above. I think that > the answer has to be clearly explained in the manual because they are not as > straightforward. And a first rapid test shows that these issues seem to be > problematic in your implementation: > > http://164.15.12.207/grass/v_distance_lines.png > http://164.15.12.207/grass/v_distance_areas.png > > red: from features (quickly digitized test data available here: > http://164.15.12.207/grass/v_distance_testdata.tgz) > black: to features (roadsmajor and urbanarea from nc_spm_08) > green: connecting lines between from and to feature Thanks for testing! These issues should be fixed, at least conforming to my explanation above, in r53401. Markus M ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance anything to anything
On 13/10/12 15:51, Markus Metz wrote: In GRASS7, v.distance can now calculate distances from point,line,boundary,centroid,area to point,line,boundary,centroid,area. So how does it calculate the distance between two lines (lines or boundaries) ? Between closest vertices ? What about lines that cross several other lines, or lines that cross each other at several points ? In GRASS 6, v.distance can calculate distances only from point,centroid to point,line,boundary,centroid,area. AFAIK, this was due to the conceptual issue mentioned above. I think that the answer has to be clearly explained in the manual because they are not as straightforward. And a first rapid test shows that these issues seem to be problematic in your implementation: http://164.15.12.207/grass/v_distance_lines.png http://164.15.12.207/grass/v_distance_areas.png red: from features (quickly digitized test data available here: http://164.15.12.207/grass/v_distance_testdata.tgz) black: to features (roadsmajor and urbanarea from nc_spm_08) green: connecting lines between from and to feature Moritz ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance anything to anything
Yip, great stuff. On 14 October 2012 04:06, Paulo van Breugel wrote: > + Great improvement > > > On Sat, Oct 13, 2012 at 3:51 PM, Markus Metz < > markus.metz.gisw...@gmail.com> wrote: > >> In GRASS7, v.distance can now calculate distances from >> point,line,boundary,centroid,area to >> point,line,boundary,centroid,area. >> >> In GRASS 6, v.distance can calculate distances only from >> point,centroid to point,line,boundary,centroid,area. >> >> Markus M >> ___ >> grass-user mailing list >> grass-user@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/grass-user >> > > > ___ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > > ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance anything to anything
+ Great improvement On Sat, Oct 13, 2012 at 3:51 PM, Markus Metz wrote: > In GRASS7, v.distance can now calculate distances from > point,line,boundary,centroid,area to > point,line,boundary,centroid,area. > > In GRASS 6, v.distance can calculate distances only from > point,centroid to point,line,boundary,centroid,area. > > Markus M > ___ > grass-user mailing list > grass-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/grass-user > ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.distance problem
Hi v.distance is not transferring attributes and I can't figure out why. It's worked before on similar data but not this time around: v.distance --overwrite from=route1pavementnodes@PERMANENT to=route1stands@PERMANENT to_type=area output=route1pavementnodes_conn_lines dmax=2 upload=to_attr column=stand_id to_column=stand_id ... 100% 6702 categories read from the map 6702 categories exist in the table 6702 categories read from the map don't exist in the table 0 records updated v.distance complete. output lines are generated but no attributes transferred. Is there some data preparation step I'm missing perhaps? GRASS 6.4.1 Gavin ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] 'v.distance'
Dear List, I have a points vector file, which I use as input in 'v.distance' to create a new vector file of lines (showing the minimum distance to the coast). The output is naturally a vector file that contains lines between each point and the sea. However, I realize that the output map cannot be queried. Even if I have GRASS connect the new (lines) vector file with the points as the second layer, querying of the lines does not return results. What I want to do is to assign CAT numbers to each line (it can be same with the CAT# of its point of origin) so that I can display lines individually in the new lines vector file for further analyses. Thank you for your help! Bulent ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] V.distance - to_angle
Hi, Trying to capture directions in v.distance. The manual says that to_angle is measured: "Counterclockwise from positive x axis, in radians, which is between -PI and PI inclusive." But: I'm getting a value of 0.83 for something which on a compass would be about 170 degrees from North. If I assume that a line in this direction is -Pi > ...then I would expect that as we rotate to here <- ...we approach 0 So I would expect something pointing nearly south to be a value of about 1/2 Pi - not 0.8, anyhow. Or have I misread the manual? Richard ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.distance bug (got the right module name this time!)
Running Grass-6.4.0RC5, using the v.distance -a option (all features), the creation of an output table shows a bug. If I try to use two output columns, v.distance is only picking up one column name. Example in Spearfish: v.distance from=archsites to=bugsites -a upload=dist,to_attr column=distant,to_cat to_column=cat ...works fine to output results to screen. Add the table option: v.distance from=archsites to=bugsites -a upload=dist,to_attr column=distant,to_cat to_column=cat table=distance_report ...brings the following error: DBMI-DBF driver error: Column 'distance' already exists (duplicate name) Cannot create table. Error in db_execute_immediate() Unable to create table: 'create table distance_report (from_cat integer, distance double precision, distance double precision )' The same error occurs using the MySQL and Sqlite drivers. For now, I'll pipeline the screen output to a text file. Richard C ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance "debug" option removed
Richard wrote: > I only just noticed that in the new versions, v.distance > has had the debug option removed. > > That's a pity, because I was using it as a feature, to > preserve the overlap areas between buffered areas as > distinct objects. > > So - how hard would it be to return debug=buffer to > v.distance? are you sure it wasn't v.buffer? If so, it's a totally new module. Hamish ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.distance "debug" option removed
Hi, I only just noticed that in the new versions, v.distance has had the debug option removed. That's a pity, because I was using it as a feature, to preserve the overlap areas between buffered areas as distinct objects. So - how hard would it be to return debug=buffer to v.distance? Richard ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance warning (WARNING: more cats of to_layer)
Hi, it means that some of areas have multiple assigned categories, try to open with v.digit and check categories of area centroids. or print categories using v.category module, e.g. v.category map type=centroid option=print layer=1 where layer is same as to_layer from your v.distance calling (probably 1) you will find some multiple categories, e.g. ... 24 25 21/22/23/24/28 29 ... In this case v.distance use only cat '28' (last found). Martin 2008/3/14, Corrado <[EMAIL PROTECTED]>: > Dear Martin, > > does that mean that there are several areas (that is more than one) in the to > vector that satisfy the condition (for example: dmax=100) for each point in > the from vector? > > > On Wednesday 12 March 2008 15:23:46 Martin Landa wrote: > > Hi, > > > > in your case the vector map (given as 'to' in v.distance) contains > > some areas (bunch of boundaries and centroid inside). Category number > > of area is assigned to the centroid. Geometry feature (point, line, > > boundary, centroid, face or kernel) can have more categories in > > general. The message from v.distance warns you that there are more > > categories assigned to the area (i.e. centroid) in given layer > > (to_layer). The last found category in given layer is taken for > > computation, maybe v.distance should be fixed to handle also multiple > > categories in one layer(?) > > > > Martin > > > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > > Dear Martin, > > > > > > I do not understand what you mean. Could you please explain? > > > > > > On Wednesday 12 March 2008 14:09:46 you wrote: > > > > Hi, > > > > > > > > it means that given vector feature from 'to' map (layer 'to_layers') > > > > has more then one category. Maybe it would make sense to change > > > > warning text to something less cryptic. > > > > > > > > Martin > > > > > > > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > > > > Dear Martin, > > > > > > > > > > I am using 6.2.3. > > > > > > > > > > On Wednesday 12 March 2008 13:31:49 you wrote: > > > > > > Hi, > > > > > > > > > > > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > > > > > > what does the warning: > > > > > > > > > > > > > > WARNING: more cats of to layer > > > > > > > > > > > > > > mean, when you execute the command v.distance? > > > > > > > > > > > > which GRASS version are you using? I cannot find such kind of > > > > > > message in grass_trunk. > > > > > > > > > > > > Martin > > > > > > > > > > Best Regards > > > > > -- > > > > > Corrado Topi > > > > > > > > > > Global Climate Change and Biodiversity > > > > > Area 18,Department of Biology > > > > > University of York, York, YO10 5YW, UK > > > > > Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] > > > > > > Best Regards > > > -- > > > Corrado Topi > > > > > > Global Climate Change and Biodiversity > > > Area 18,Department of Biology > > > University of York, York, YO10 5YW, UK > > > Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] > > Best Regards > -- > Corrado Topi > > Global Climate Change and Biodiversity > Area 18,Department of Biology > University of York, York, YO10 5YW, UK > Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] > -- Martin Landa * http://gama.fsv.cvut.cz/~landa * ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance warning (WARNING: more cats of to_layer)
Dear Martin, does that mean that there are several areas (that is more than one) in the to vector that satisfy the condition (for example: dmax=100) for each point in the from vector? On Wednesday 12 March 2008 15:23:46 Martin Landa wrote: > Hi, > > in your case the vector map (given as 'to' in v.distance) contains > some areas (bunch of boundaries and centroid inside). Category number > of area is assigned to the centroid. Geometry feature (point, line, > boundary, centroid, face or kernel) can have more categories in > general. The message from v.distance warns you that there are more > categories assigned to the area (i.e. centroid) in given layer > (to_layer). The last found category in given layer is taken for > computation, maybe v.distance should be fixed to handle also multiple > categories in one layer(?) > > Martin > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > Dear Martin, > > > > I do not understand what you mean. Could you please explain? > > > > On Wednesday 12 March 2008 14:09:46 you wrote: > > > Hi, > > > > > > it means that given vector feature from 'to' map (layer 'to_layers') > > > has more then one category. Maybe it would make sense to change > > > warning text to something less cryptic. > > > > > > Martin > > > > > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > > > Dear Martin, > > > > > > > > I am using 6.2.3. > > > > > > > > On Wednesday 12 March 2008 13:31:49 you wrote: > > > > > Hi, > > > > > > > > > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > > > > > what does the warning: > > > > > > > > > > > > WARNING: more cats of to layer > > > > > > > > > > > > mean, when you execute the command v.distance? > > > > > > > > > > which GRASS version are you using? I cannot find such kind of > > > > > message in grass_trunk. > > > > > > > > > > Martin > > > > > > > > Best Regards > > > > -- > > > > Corrado Topi > > > > > > > > Global Climate Change and Biodiversity > > > > Area 18,Department of Biology > > > > University of York, York, YO10 5YW, UK > > > > Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] > > > > Best Regards > > -- > > Corrado Topi > > > > Global Climate Change and Biodiversity > > Area 18,Department of Biology > > University of York, York, YO10 5YW, UK > > Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] Best Regards -- Corrado Topi Global Climate Change and Biodiversity Area 18,Department of Biology University of York, York, YO10 5YW, UK Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance warning (WARNING: more cats of to_layer)
Hi, in your case the vector map (given as 'to' in v.distance) contains some areas (bunch of boundaries and centroid inside). Category number of area is assigned to the centroid. Geometry feature (point, line, boundary, centroid, face or kernel) can have more categories in general. The message from v.distance warns you that there are more categories assigned to the area (i.e. centroid) in given layer (to_layer). The last found category in given layer is taken for computation, maybe v.distance should be fixed to handle also multiple categories in one layer(?) Martin 2008/3/12, Corrado <[EMAIL PROTECTED]>: > Dear Martin, > > I do not understand what you mean. Could you please explain? > > > On Wednesday 12 March 2008 14:09:46 you wrote: > > Hi, > > > > it means that given vector feature from 'to' map (layer 'to_layers') > > has more then one category. Maybe it would make sense to change > > warning text to something less cryptic. > > > > Martin > > > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > > Dear Martin, > > > > > > I am using 6.2.3. > > > > > > On Wednesday 12 March 2008 13:31:49 you wrote: > > > > Hi, > > > > > > > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > > > > what does the warning: > > > > > > > > > > WARNING: more cats of to layer > > > > > > > > > > mean, when you execute the command v.distance? > > > > > > > > which GRASS version are you using? I cannot find such kind of message > > > > in grass_trunk. > > > > > > > > Martin > > > > > > Best Regards > > > -- > > > Corrado Topi > > > > > > Global Climate Change and Biodiversity > > > Area 18,Department of Biology > > > University of York, York, YO10 5YW, UK > > > Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] > > > Best Regards > -- > Corrado Topi > > Global Climate Change and Biodiversity > Area 18,Department of Biology > University of York, York, YO10 5YW, UK > Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] > -- Martin Landa * http://gama.fsv.cvut.cz/~landa * ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance warning (WARNING: more cats of to_layer)
[fwd to list] Hi, it means that given vector feature from 'to' map (layer 'to_layers') has more then one category. Maybe it would make sense to change warning text to something less cryptic. Martin 2008/3/12, Corrado <[EMAIL PROTECTED]>: > Dear Martin, > > I am using 6.2.3. > > > On Wednesday 12 March 2008 13:31:49 you wrote: > > Hi, > > > > 2008/3/12, Corrado <[EMAIL PROTECTED]>: > > > what does the warning: > > > > > > WARNING: more cats of to layer > > > > > > mean, when you execute the command v.distance? > > > > which GRASS version are you using? I cannot find such kind of message > > in grass_trunk. > > > > Martin > > > > Best Regards > -- > Corrado Topi > > Global Climate Change and Biodiversity > Area 18,Department of Biology > University of York, York, YO10 5YW, UK > Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] > -- Martin Landa * http://gama.fsv.cvut.cz/~landa * -- Martin Landa * http://gama.fsv.cvut.cz/~landa * ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] v.distance warning (WARNING: more cats of to_layer)
Hi, 2008/3/12, Corrado <[EMAIL PROTECTED]>: > what does the warning: > > WARNING: more cats of to layer > > mean, when you execute the command v.distance? which GRASS version are you using? I cannot find such kind of message in grass_trunk. Martin -- Martin Landa * http://gama.fsv.cvut.cz/~landa * ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.distance warning (WARNING: more cats of to_layer)
Dear friends, what does the warning: WARNING: more cats of to layer mean, when you execute the command v.distance? Best Regards -- Corrado Topi Global Climate Change and Biodiversity Area 18,Department of Biology University of York, York, YO10 5YW, UK Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] v.distance with upload=to_attr: is it possible to specify more than one column?
Dear friends, when using v.distance with upload=to_attr is it possible to specify more than one column? In other words, is it possible to update more than one column from the "to table"? Example of what I tried to do: v.distance from=species to=sssi dmax=0 upload=to_attr to_colum=cat,gid col=sssi_cat,sssi_id but I get warnings! Is there another way to do it? Best Regards -- Corrado Topi Global Climate Change and Biodiversity Area 18,Department of Biology University of York, York, YO10 5YW, UK Phone: + 44 (0) 1904 328645, E-mail: [EMAIL PROTECTED] ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
Re: [GRASS-user] V.distance
On Jan 8, 2008 11:54 PM, Richard Chirgwin <[EMAIL PROTECTED]> wrote: > What algorithm does V.distance use for calculations? For cartesian coordinate systems it currently uses 2D/3D Pythagoras. Vect_line_distance() in http://trac.osgeo.org/grass/browser/grass/trunk/lib/vector/Vlib/line.c For LatLong it uses geodesic distance calculation (reference): Vect_line_geodesic_length() in http://trac.osgeo.org/grass/browser/grass/trunk/lib/vector/Vlib/line.c which calls http://trac.osgeo.org/grass/browser/grass/trunk/lib/gis/geodist.c Markus PS: please update your address book to use grass-user@lists.osgeo.org ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
[GRASS-user] V.distance
What algorithm does V.distance use for calculations? Richard Chirgwin ___ grass-user mailing list grass-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/grass-user
