Re: [Qgis-user] Getting landuse information for several circular polygons
Hi Manuel, I also suggest you to consider the analysis tools provided by Sextante [1]. It offers bridges to other GIS analysis software, like GRASS and SAGA, and they have a lot of analysis functionalities and algorithms. For example GRASS has the r.li.* [1 ]set of commamds for landscape analysis. giovanni [1] http://plugins.qgis.org/plugins/sextante/ [2] http://grass.fbk.eu/grass64/manuals/html64_user/r.li.html 2012/7/17 Manuel Spínola mspinol...@gmail.com Thank you very much Simon. No offense at all, by the contrary, very helpful and very grateful for your message. I will check all the stuff you suggested. I teach landscape ecology and wildlife habitat evaluation for master students, I use R for some topics, but I want use more QGIS and stay away from commercial software. Our students (from all over Latin America) usually work under very restrictive budgets. Best, Manuel 2012/7/16 Simon Cropper simoncrop...@fossworkflowguides.com Manuel, I am not aware of any specific tutorials for doing this work in QGIS. No offense but these tasks are relatively basic. Your comment I found this task kind of difficult to do in QGIS is suggestive that you have difficulty in either basic GIS concepts or extrapolating your existing knowledge from a commercial package to QGIS. *Assuming you stick with QGIS* Micha Silver has provided a tutorial called GIS basics with Quantum GIS http://www.osgeo.org/node/1058 that may help you master the basics. The QGIS website has a great section called How do I do that in QGIS? that covers alot of material http://hub.qgis.org/projects/** quantum-gis/wiki/How_do_I_do_**that_in_QGIS#How-do-I-do-that-**in-QGIShttp://hub.qgis.org/projects/quantum-gis/wiki/How_do_I_do_that_in_QGIS#How-do-I-do-that-in-QGIS. Note the large number of videos on youtube -- sometimes seeing it done can help. *Assuming you are considering an alternative* The OSGeo Educational Content Inventory also has a wide variety of other educational material available that might also help fill in the gaps. http://www.osgeo.org/**educational_contenthttp://www.osgeo.org/educational_content Finally, QGIS is not the only fosGIS out there. Check out what is on offer on the LiveDVD (http://wiki.osgeo.org/wiki/**Live_GIS_Dischttp://wiki.osgeo.org/wiki/Live_GIS_Disc ). Personally, I found using gvSIG relatively easy when moving from ArcView. Unfortunately the bulk of the tutorials are in Spanish; unlike QGIS which are predominantly in English. See my website for details and a list of ecological tutorials I have prepared to date. *Final Comment* All this material is predicated by the premise that you actually know what things are called. Reprojection and transformation is a good example. Projection, SRS and CRS another. When stuck, posing a problem on the forums can help as others can help you with terminology and suggest methods to solve you problems. I hope this helps. On 17/07/12 11:50, Manuel Spínola wrote: What I am trying to do is a very common task in landscape ecology. The buffer could be considered a landscape for some species and some metrics could be obtained for these landscapes, however, I found this task kind of difficult to do in QGIS. Any input on this? Is there any oriented landscape ecology tutorial for QGIS. [snip] -- Cheers Simon Simon Cropper - Open Content Creator Free and Open Source Software Workflow Guides --**-- Introduction http://www.fossworkflowguides.**comhttp://www.fossworkflowguides.com GIS Packages http://www.fossworkflowguides.**com/gishttp://www.fossworkflowguides.com/gis bash / Python http://www.fossworkflowguides.**com/scriptinghttp://www.fossworkflowguides.com/scripting -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de ríohttps://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/ ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
[Qgis-user] Getting landuse information for several circular polygons
Dear list members, I have a landuse layer and another layer with 20 circular polygons (buffers) and I want to obtain the amount of each landuse category within each circular polygon. I tried clip from Geoprocessing Tools but I dont get the information individualized for each circular polygon. Is it possible to get the landuse within each circular polygon in one step? Best, Manuel -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/ ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Getting landuse information for several circular polygons
On 16/07/2012 20:22, Manuel Spínola wrote: Dear list members, I have a landuse layer and another layer with 20 circular polygons (buffers) and I want to obtain the amount of each landuse category within each circular polygon. I tried clip from Geoprocessing Tools but I dont get the information individualized for each circular polygon. Is it possible to get the landuse within each circular polygon in one step? Not exactly one step but... If you don't mind to drop the vectors into spatialite, then a query can update the buffers layer with area of each landuse category as follows: Suppose buffers has a label column, and there are landuse categories lu1, lu2, lu3, then: SELECT b.label AS Buffer, ST_Area(ST_Intersection(b.Geometry, l.Geometry)) AS LandUse1 FROM buffers AS b, landuse AS l WHERE l.category='lu1' AND ST_Intersects(b.Geometry, l.Geometry) GROUP BY b.buff_id; If you add columns to the buffers table to hold total area for each landuse category:: ALTER TABLE buffers ADD COLUMN lu1_area float; ALTER TABLE buffers ADD COLUMN lu2_area float; then you'd update each column like so: UPDATE buffers SET lu1_area=( SELECT ST_Area(ST_Intersection(b.Geometry, l.Geometry)) AS LandUse1 FROM buffers AS b, landuse AS l WHERE l.category='lu1' AND ST_Intersects(b.Geometry, l.Geometry) AND b.label=buffers.label ); HTH, Micha Best, Manuel -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mailto:mspin...@una.ac.cr mspinol...@gmail.com mailto:mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/ This mail was received via Mail-SeCure System. ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user This mail was received via Mail-SeCure System. ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Getting landuse information for several circular polygons
Thank you very much Micha. Your suggestion is based on writing a code, right? I am doing this for teaching purposes, is it possible to do the same based on the menu of QGIS? Best, Manuel 2012/7/16 Micha Silver mi...@arava.co.il On 16/07/2012 20:22, Manuel Spínola wrote: Dear list members, I have a landuse layer and another layer with 20 circular polygons (buffers) and I want to obtain the amount of each landuse category within each circular polygon. I tried clip from Geoprocessing Tools but I dont get the information individualized for each circular polygon. Is it possible to get the landuse within each circular polygon in one step? Not exactly one step but... If you don't mind to drop the vectors into spatialite, then a query can update the buffers layer with area of each landuse category as follows: Suppose buffers has a label column, and there are landuse categories lu1, lu2, lu3, then: SELECT b.label AS Buffer, ST_Area(ST_Intersection(b.**Geometry, l.Geometry)) AS LandUse1 FROM buffers AS b, landuse AS l WHERE l.category='lu1' AND ST_Intersects(b.Geometry, l.Geometry) GROUP BY b.buff_id; If you add columns to the buffers table to hold total area for each landuse category:: ALTER TABLE buffers ADD COLUMN lu1_area float; ALTER TABLE buffers ADD COLUMN lu2_area float; then you'd update each column like so: UPDATE buffers SET lu1_area=( SELECT ST_Area(ST_Intersection(b.**Geometry, l.Geometry)) AS LandUse1 FROM buffers AS b, landuse AS l WHERE l.category='lu1' AND ST_Intersects(b.Geometry, l.Geometry) AND b.label=buffers.label ); HTH, Micha Best, Manuel -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mailto:mspin...@una.ac.cr mspinol...@gmail.com mailto:mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/** site/lobitoderio/ https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/** This mail was received via Mail-SeCure System. __**_ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/**mailman/listinfo/qgis-userhttp://lists.osgeo.org/mailman/listinfo/qgis-user This mail was received via Mail-SeCure System. -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/ ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Getting landuse information for several circular polygons
Manuel, Once you clip the layers, break the multi-part components apart use the following menu sequence Vector Geometry Tools Multiparts to Single Parts -- then they can be summed. You will need to relate you bits back to your buffer layers however, to match which bit goes in which buffer. Alternatively, and easier in my mind, you could Union your layers. This creates an exploded layer where each bit has attributes of both parent layers. You can then delete those elements that do not have a buffer value. Two steps but less messy. On 17/07/12 03:22, Manuel Spínola wrote: Dear list members, I have a landuse layer and another layer with 20 circular polygons (buffers) and I want to obtain the amount of each landuse category within each circular polygon. I tried clip from Geoprocessing Tools but I dont get the information individualized for each circular polygon. Is it possible to get the landuse within each circular polygon in one step? Best, Manuel -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mailto:mspin...@una.ac.cr mspinol...@gmail.com mailto:mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/ ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user -- Cheers Simon Simon Cropper - Open Content Creator Free and Open Source Software Workflow Guides Introduction http://www.fossworkflowguides.com GIS Packages http://www.fossworkflowguides.com/gis bash / Pythonhttp://www.fossworkflowguides.com/scripting ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Getting landuse information for several circular polygons
Thank you very much Simon. That works, specially the second option. What I am trying to do is a very common task in landscape ecology. The buffer could be considered a landscape for some species and some metrics could be obtained for these landscapes, however, I found this task kind of difficult to do in QGIS. Any input on this? Is there any oriented landscape ecology tutorial for QGIS. Best, Manuel 2012/7/16 Simon Cropper simoncrop...@fossworkflowguides.com Manuel, Once you clip the layers, break the multi-part components apart use the following menu sequence Vector Geometry Tools Multiparts to Single Parts -- then they can be summed. You will need to relate you bits back to your buffer layers however, to match which bit goes in which buffer. Alternatively, and easier in my mind, you could Union your layers. This creates an exploded layer where each bit has attributes of both parent layers. You can then delete those elements that do not have a buffer value. Two steps but less messy. On 17/07/12 03:22, Manuel Spínola wrote: Dear list members, I have a landuse layer and another layer with 20 circular polygons (buffers) and I want to obtain the amount of each landuse category within each circular polygon. I tried clip from Geoprocessing Tools but I dont get the information individualized for each circular polygon. Is it possible to get the landuse within each circular polygon in one step? Best, Manuel -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mailto:mspin...@una.ac.cr mspinol...@gmail.com mailto:mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/**site/lobitoderio/https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/** __**_ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/**mailman/listinfo/qgis-userhttp://lists.osgeo.org/mailman/listinfo/qgis-user -- Cheers Simon Simon Cropper - Open Content Creator Free and Open Source Software Workflow Guides --**-- Introduction http://www.fossworkflowguides.**comhttp://www.fossworkflowguides.com GIS Packages http://www.fossworkflowguides.**com/gishttp://www.fossworkflowguides.com/gis bash / Python http://www.fossworkflowguides.**com/scriptinghttp://www.fossworkflowguides.com/scripting __**_ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/**mailman/listinfo/qgis-userhttp://lists.osgeo.org/mailman/listinfo/qgis-user -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/ ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Getting landuse information for several circular polygons
Manuel, I am not aware of any specific tutorials for doing this work in QGIS. No offense but these tasks are relatively basic. Your comment I found this task kind of difficult to do in QGIS is suggestive that you have difficulty in either basic GIS concepts or extrapolating your existing knowledge from a commercial package to QGIS. *Assuming you stick with QGIS* Micha Silver has provided a tutorial called GIS basics with Quantum GIS http://www.osgeo.org/node/1058 that may help you master the basics. The QGIS website has a great section called How do I do that in QGIS? that covers alot of material http://hub.qgis.org/projects/quantum-gis/wiki/How_do_I_do_that_in_QGIS#How-do-I-do-that-in-QGIS. Note the large number of videos on youtube -- sometimes seeing it done can help. *Assuming you are considering an alternative* The OSGeo Educational Content Inventory also has a wide variety of other educational material available that might also help fill in the gaps. http://www.osgeo.org/educational_content Finally, QGIS is not the only fosGIS out there. Check out what is on offer on the LiveDVD (http://wiki.osgeo.org/wiki/Live_GIS_Disc). Personally, I found using gvSIG relatively easy when moving from ArcView. Unfortunately the bulk of the tutorials are in Spanish; unlike QGIS which are predominantly in English. See my website for details and a list of ecological tutorials I have prepared to date. *Final Comment* All this material is predicated by the premise that you actually know what things are called. Reprojection and transformation is a good example. Projection, SRS and CRS another. When stuck, posing a problem on the forums can help as others can help you with terminology and suggest methods to solve you problems. I hope this helps. On 17/07/12 11:50, Manuel Spínola wrote: What I am trying to do is a very common task in landscape ecology. The buffer could be considered a landscape for some species and some metrics could be obtained for these landscapes, however, I found this task kind of difficult to do in QGIS. Any input on this? Is there any oriented landscape ecology tutorial for QGIS. [snip] -- Cheers Simon Simon Cropper - Open Content Creator Free and Open Source Software Workflow Guides Introduction http://www.fossworkflowguides.com GIS Packages http://www.fossworkflowguides.com/gis bash / Pythonhttp://www.fossworkflowguides.com/scripting ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
Re: [Qgis-user] Getting landuse information for several circular polygons
Thank you very much Simon. No offense at all, by the contrary, very helpful and very grateful for your message. I will check all the stuff you suggested. I teach landscape ecology and wildlife habitat evaluation for master students, I use R for some topics, but I want use more QGIS and stay away from commercial software. Our students (from all over Latin America) usually work under very restrictive budgets. Best, Manuel 2012/7/16 Simon Cropper simoncrop...@fossworkflowguides.com Manuel, I am not aware of any specific tutorials for doing this work in QGIS. No offense but these tasks are relatively basic. Your comment I found this task kind of difficult to do in QGIS is suggestive that you have difficulty in either basic GIS concepts or extrapolating your existing knowledge from a commercial package to QGIS. *Assuming you stick with QGIS* Micha Silver has provided a tutorial called GIS basics with Quantum GIS http://www.osgeo.org/node/1058 that may help you master the basics. The QGIS website has a great section called How do I do that in QGIS? that covers alot of material http://hub.qgis.org/projects/** quantum-gis/wiki/How_do_I_do_**that_in_QGIS#How-do-I-do-that-**in-QGIShttp://hub.qgis.org/projects/quantum-gis/wiki/How_do_I_do_that_in_QGIS#How-do-I-do-that-in-QGIS. Note the large number of videos on youtube -- sometimes seeing it done can help. *Assuming you are considering an alternative* The OSGeo Educational Content Inventory also has a wide variety of other educational material available that might also help fill in the gaps. http://www.osgeo.org/**educational_contenthttp://www.osgeo.org/educational_content Finally, QGIS is not the only fosGIS out there. Check out what is on offer on the LiveDVD (http://wiki.osgeo.org/wiki/**Live_GIS_Dischttp://wiki.osgeo.org/wiki/Live_GIS_Disc ). Personally, I found using gvSIG relatively easy when moving from ArcView. Unfortunately the bulk of the tutorials are in Spanish; unlike QGIS which are predominantly in English. See my website for details and a list of ecological tutorials I have prepared to date. *Final Comment* All this material is predicated by the premise that you actually know what things are called. Reprojection and transformation is a good example. Projection, SRS and CRS another. When stuck, posing a problem on the forums can help as others can help you with terminology and suggest methods to solve you problems. I hope this helps. On 17/07/12 11:50, Manuel Spínola wrote: What I am trying to do is a very common task in landscape ecology. The buffer could be considered a landscape for some species and some metrics could be obtained for these landscapes, however, I found this task kind of difficult to do in QGIS. Any input on this? Is there any oriented landscape ecology tutorial for QGIS. [snip] -- Cheers Simon Simon Cropper - Open Content Creator Free and Open Source Software Workflow Guides --**-- Introduction http://www.fossworkflowguides.**comhttp://www.fossworkflowguides.com GIS Packages http://www.fossworkflowguides.**com/gishttp://www.fossworkflowguides.com/gis bash / Python http://www.fossworkflowguides.**com/scriptinghttp://www.fossworkflowguides.com/scripting -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA mspin...@una.ac.cr mspinol...@gmail.com Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río https://sites.google.com/site/lobitoderio/ Institutional website: ICOMVIS http://www.icomvis.una.ac.cr/ ___ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user
