Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
Il giorno mar, 01/03/2011 alle 23.31 -0800, Dan Putler ha scritto: > Thanks for your advise. Glad you liked it. I must add, another advantage is that writing your script is most easily done through QGIS, where you can test each individual command, playing with options and parameters, and simply copying the readymade command line to a text file. All the best, and let us know how it is going. -- http://www.faunalia.it/pc ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
Hi Paolo, Your point is well taken. What seem to be the best solutions involve reading in a shapefile and then writing out a new one. I was starting to lean toward either PostGIS or Spatialite by using a SQL script sourced within the relevant cli shell since my guess was that they would scale much better than any Python code I was likely to write. I think I could automate things more with GRASS shell scripts than with SQL scripts (there are over 3000 counties in the US). The geometry cleaning GRASS does is a two edged sword, having all the benefits you indicate, but at the cost of increased processing time. However, my guess is that the benefits of the cleaning are worth the cost. Thanks for your advise. Dan On 03/01/2011 10:57 PM, Paolo Cavallini wrote: Il giorno mar, 01/03/2011 alle 23.25 +0100, Paolo Corti ha scritto: Your only option here could be to use GRASS, but as far as I know you need to import your shapefile to the GRASS database, use a GRASS command (v.reclass [0]) and export back to shapefile the result, so it is not very direct. Not very direct, but it's only one more command (v.in.ogr), with the additional bonus that importing into GRASS you can clean up invalid topologies, close empty gaps, remove unwanted overlaps, etc. All the best. ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
Il giorno mar, 01/03/2011 alle 23.25 +0100, Paolo Corti ha scritto: > Your only option here could be to use GRASS, but as far as I know you > need to import your shapefile to the GRASS database, use a GRASS > command (v.reclass [0]) and export back to shapefile the result, so it > is not very direct. Not very direct, but it's only one more command (v.in.ogr), with the additional bonus that importing into GRASS you can clean up invalid topologies, close empty gaps, remove unwanted overlaps, etc. All the best. -- http://www.faunalia.it/pc ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
Hi Paolo, Simon, and Noli, Thanks for this. It both answered my question as to whether there was an existing command line tool I had just overlooked (the answer is "no"), and what were my choices for something that could fairly easily be implemented if there wasn't an existing tool (the answer is "several"). At this point I'm going to look more deeply into several of these recommendations. Thanks again, Dan On 03/01/2011 06:55 PM, Noli Sicad wrote: Hi Simon, That sounds great. I thought I remembered having read somewhere that Spatialite could accept commands in this way but could not find a link to the webpage when putting together my reply. Can you provide a step by step outline of the code necessary to do this? It is in Spatialite Google Groups, here are the links. http://groups.google.com/group/spatialite-users/browse_thread/thread/7ecd6ccae76d3495/8683876813398de5?lnk=gst&q=Shapefile+#8683876813398de5 ST_Union http://groups.google.com/group/spatialite-users/browse_thread/thread/2c8cc54d4b253979/78bc0b7eae6b1c38?lnk=gst&q=GUnion#78bc0b7eae6b1c38 Why is it necessary to create a CSV? Can't Spatialite manipulate shapefiles directly in a virtual table? It is needed for matching e.g. ~~ CREATE TABLE workplan AS SELECT * FROM property_mp JOIN planning ON (property_mp.PR_PROPNUM = planning.PR_PROP_No); ~~ where planning.PR_PROP_No is from CSV table. You can manipulate Shapefile as Virtual Shapefile. However, you need a table for the criteria to be join and dissolve. It is easier to get the attribute table you need from the shapefile, if you like. Using MMQGIS plugin in QGIS you can export the attribute table into CSV file with ease. Noli ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
Hi Simon, > That sounds great. > > I thought I remembered having read somewhere that Spatialite could > accept commands in this way but could not find a link to the webpage > when putting together my reply. > > Can you provide a step by step outline of the code necessary to do this? It is in Spatialite Google Groups, here are the links. http://groups.google.com/group/spatialite-users/browse_thread/thread/7ecd6ccae76d3495/8683876813398de5?lnk=gst&q=Shapefile+#8683876813398de5 ST_Union http://groups.google.com/group/spatialite-users/browse_thread/thread/2c8cc54d4b253979/78bc0b7eae6b1c38?lnk=gst&q=GUnion#78bc0b7eae6b1c38 > Why is it necessary to create a CSV? Can't Spatialite manipulate > shapefiles directly in a virtual table? It is needed for matching e.g. ~~ CREATE TABLE workplan AS SELECT * FROM property_mp JOIN planning ON (property_mp.PR_PROPNUM = planning.PR_PROP_No); ~~ where planning.PR_PROP_No is from CSV table. You can manipulate Shapefile as Virtual Shapefile. However, you need a table for the criteria to be join and dissolve. It is easier to get the attribute table you need from the shapefile, if you like. Using MMQGIS plugin in QGIS you can export the attribute table into CSV file with ease. Noli ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
On 02/03/11 12:41, Noli Sicad wrote: Dan, I am using Spatialite CLI for to this job. 1. Import shapefile into Spatialite 2. Create CSV.file for the counties 3. Use Vitual table for counties.csv 4. Use ST_UNION to create a new table with dissolved boundaries 5. Dump the new spatialite table to Shapefile file Noli On 3/2/11, Simon Cropper wrote: On 02/03/11 08:37, Dan Putler wrote: All, Is there a FOSS command line tool that runs under Linux for dissolving polygon boundaries based on a field in an attribute table that (ideally) works directly with shapefiles? There are a number of non-cli tools out there, but I'm working with all US counties on a county by county basis, and wanted to avoid importing each individual county into another product. Dan ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss Dan, My understanding is that SAGA can be accessed using the command line. Check out this page... http://sourceforge.net/apps/trac/saga-gis/wiki/Executing%20Modules%20with%20SAGA%20CMD If you intend to create a bash script to dissolve your shapefiles, it would be just as easy I presume to write a script that opens the shapefile, dissolves the polygons, then closes it; progressively working through the list of counties. Remember most packages have the ability to run script. gvSIG uses Jpython, QGIS python, etc. I fact from what I can tell you can actually import QGIS modules into python. http://desktopgisbook.com/Creating_a_Standalone_GIS_Application_1 -- Cheers Simon Simon Cropper Principal Consultant Botanicus Australia Pty Ltd PO Box 160, Sunshine, VIC W: www.botanicusaustralia.com.au ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss Noli, That sounds great. I thought I remembered having read somewhere that Spatialite could accept commands in this way but could not find a link to the webpage when putting together my reply. Can you provide a step by step outline of the code necessary to do this? Why is it necessary to create a CSV? Can't Spatialite manipulate shapefiles directly in a virtual table? -- Cheers Simon Simon Cropper Principal Consultant Botanicus Australia Pty Ltd PO Box 160, Sunshine, VIC W: www.botanicusaustralia.com.au ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
Dan, I am using Spatialite CLI for to this job. 1. Import shapefile into Spatialite 2. Create CSV.file for the counties 3. Use Vitual table for counties.csv 4. Use ST_UNION to create a new table with dissolved boundaries 5. Dump the new spatialite table to Shapefile file Noli On 3/2/11, Simon Cropper wrote: > On 02/03/11 08:37, Dan Putler wrote: >> All, >> >> Is there a FOSS command line tool that runs under Linux for dissolving >> polygon boundaries based on a field in an attribute table that (ideally) >> works directly with shapefiles? There are a number of non-cli tools out >> there, but I'm working with all US counties on a county by county basis, >> and wanted to avoid importing each individual county into another product. >> >> Dan >> ___ >> Discuss mailing list >> Discuss@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/discuss >> >> > > Dan, > > My understanding is that SAGA can be accessed using the command line. > Check out this page... > http://sourceforge.net/apps/trac/saga-gis/wiki/Executing%20Modules%20with%20SAGA%20CMD > > If you intend to create a bash script to dissolve your shapefiles, it > would be just as easy I presume to write a script that opens the > shapefile, dissolves the polygons, then closes it; progressively working > through the list of counties. Remember most packages have the ability to > run script. gvSIG uses Jpython, QGIS python, etc. I fact from what I can > tell you can actually import QGIS modules into python. > http://desktopgisbook.com/Creating_a_Standalone_GIS_Application_1 > > > > -- > Cheers Simon > > Simon Cropper > Principal Consultant > Botanicus Australia Pty Ltd > PO Box 160, Sunshine, VIC > W: www.botanicusaustralia.com.au > ___ > Discuss mailing list > Discuss@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/discuss > ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
On 02/03/11 08:37, Dan Putler wrote: All, Is there a FOSS command line tool that runs under Linux for dissolving polygon boundaries based on a field in an attribute table that (ideally) works directly with shapefiles? There are a number of non-cli tools out there, but I'm working with all US counties on a county by county basis, and wanted to avoid importing each individual county into another product. Dan ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss Dan, My understanding is that SAGA can be accessed using the command line. Check out this page... http://sourceforge.net/apps/trac/saga-gis/wiki/Executing%20Modules%20with%20SAGA%20CMD If you intend to create a bash script to dissolve your shapefiles, it would be just as easy I presume to write a script that opens the shapefile, dissolves the polygons, then closes it; progressively working through the list of counties. Remember most packages have the ability to run script. gvSIG uses Jpython, QGIS python, etc. I fact from what I can tell you can actually import QGIS modules into python. http://desktopgisbook.com/Creating_a_Standalone_GIS_Application_1 -- Cheers Simon Simon Cropper Principal Consultant Botanicus Australia Pty Ltd PO Box 160, Sunshine, VIC W: www.botanicusaustralia.com.au ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
Re: [OSGeo-Discuss] Command line tool for dissolving polygon boundaries
> Is there a FOSS command line tool that runs under Linux for dissolving > polygon boundaries based on a field in an attribute table that (ideally) > works directly with shapefiles? There are a number of non-cli tools out > there, but I'm working with all US counties on a county by county basis, and > wanted to avoid importing each individual county into another product. Hi Dan What you need to do could easily be accomplished with GDAL and GEOS (for example with Python) or GeoTools and JTS (with Java), but as far as I know you should write yourself a script for performing this action. I don't know it there may already be production ready scripts performing what you need with this technologies. Your only option here could be to use GRASS, but as far as I know you need to import your shapefile to the GRASS database, use a GRASS command (v.reclass [0]) and export back to shapefile the result, so it is not very direct. best regards P [0] http://grass.fbk.eu/gdp/html_grass64/v.reclass.html -- Paolo Corti Geospatial software developer web: http://www.paolocorti.net twitter: @paolo_corti ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
[OSGeo-Discuss] Command line tool for dissolving polygon boundaries
All, Is there a FOSS command line tool that runs under Linux for dissolving polygon boundaries based on a field in an attribute table that (ideally) works directly with shapefiles? There are a number of non-cli tools out there, but I'm working with all US counties on a county by county basis, and wanted to avoid importing each individual county into another product. Dan ___ Discuss mailing list Discuss@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/discuss
