Tagged Questions
9
votes
2answers
212 views
Can I add an ArcToolbox tool to QGIS?
I have been using a publicly available tool in ArcGIS called SPreAD-GIS. It is a series of python scripts that are "implemented as an ArcGIS toolbox" (with tbx file).
I am new to QGIS. Is there a ...
1
vote
0answers
68 views
How to calculate weighted mean coordinates within polygons?
I'm using QGIS 1.8 on OSX 10.8.3.
I have a polygon shapefile of all of the US state legislative districts.
I also have a layer of points that are centroids of US Census Tracts, with a field for the ...
2
votes
0answers
47 views
How to use Memory layers in QGIS plugin to store results of Geoprocessing tools
I'm building a plugin to perform Multi Criteria Analysis (yes another one...). As part of my workflow intersecting vectorlayers is needed. I use QgsOverlayAnalyzer.intersection (a pity union is not ...
0
votes
0answers
55 views
How to set tolerance value of Geoprocessing tool in QGIS?
Is it possible to set tolerance value of geoprocessing tool on QGIS.
History is below.
There are two polygon which have to be the same position.
so, I set topological rule "A must covered by B" on ...
1
vote
4answers
142 views
How to create internal polygon without overlap on QGIS1.8.0
I would like to create new polygon inside the existing polygon.
It does not means donuts polygon.
I would like to have two polygon without overlapping.
I can create if I don't check "Avoid ...
3
votes
1answer
122 views
Calculate number of people within 50 km of a point
I have two data sets:
World population (raster) in EPSG:4326, from http://sedac.ciesin.columbia.edu/data/set/gpw-v3-population-density-future-estimates/data-download
A shp file with points ...
7
votes
3answers
307 views
How to sum up values of neighbouring polygons?
I hope that you can help me with the following problem: I have a vector (polygon) layer. I would like to add an attribute to the layer that - for every polygon - sums the values of a specific field of ...
6
votes
1answer
338 views
How to calculate te area between contour lines on a DEM with Qgis 1.8?
Does anyone know how to calculate the area in km² for each altitudinal band (between 100 and 200, 200 and 300...) based on a DEM? I added the contour lines with a distance of 100 metres but could not ...
5
votes
1answer
150 views
Simulate (Mock) GPS Tracks
I have the following scenario:
1) I need to create GPX files for use in testing of a mobile device.
2) The tracks to be described within will span large distances over long time periods (i.e. it's ...
0
votes
1answer
256 views
table of polygon centroids
Given a polygon layer, census tracts, how can I generate a table of centroid coordinates in QGIS, or add columns with the centroid coordinates or generate a new layer of polygon centroid points?
4
votes
3answers
544 views
How to split features?
I would like to split a shapefile in qgis according to how the polygons overlaps. Don't know how to though? See pic for explanation:
2
votes
2answers
116 views
Determine the furthest driving distance from a road layer to the nearest point of a point layer using OSM/QGIS
In a specific geographic area, I have a road layer and roughly 30 points dispersed around the geographic area as part of a point layer. Both layers are in SHP and PostGIS formats. The records from the ...
4
votes
1answer
718 views
Performing Geoprocessing SQL Queries in QGIS from a PostGIS Database
This may be a dumb question, but is there way to run a PostGIS geoprocessing SQL query in QGIS? Specifically, I am thinking of running SQLs such as ST_Union, ST_Split etc etc.
I have tried the ...
9
votes
3answers
2k views
Divide a complex shape file into a grid
I have a decently detailed shapefile with polygon/multipolygon features (the file is about 500mb). It's actually a shapefile of the entire world, with the features representing coastlines. I need to ...
3
votes
1answer
843 views
How to get point attribute from polygon layer?
I have two layer, one (A) has point features and the other (B) has polygons.
I need to produce a new table with some (the ID) or all the fields from the A table and some (the area code) or all from ...
3
votes
1answer
281 views
How to divide a polyline by intersecting isochrones
I have two shapefiles, the first representing a path (a polyline with a single category), the second representing isochrons from the same origin (point 0) which intersect the above mentioned path.
I ...
18
votes
4answers
2k views
Is there any model builder in QGIS or other open source GIS?
Like the model builder in ArcGIS Desktop to run simultaneous geoprocessing tools, is there any model builder available in QGIS or an open source GIS software.
2
votes
2answers
2k views
Can two polygon layers be merged in QGIS on a common id?
Can two polygon layers be merged in QGIS on the basis of a common id?
Update:
Ok , the dissolve tool works fine. But for instance lets say I have 10 polygons. 8 of them are together , so when ...
17
votes
5answers
2k views
How to identify clusters in vector point data?
I have a vector dataset of rural broadband data-points (how fast, etc.) and I'd like to explore if there are clusters of points with similar characteristics, and to plot polygons encompassing them.
...
6
votes
1answer
442 views
Is there a way to access QGIS plugins in Python?
Is there a way to access QGIS plugins in Python? I'd like to write a script to do some geoprocessing, and I'd like to use the clip, regular points and convex hull tools in fTools, as well as the Road ...
3
votes
2answers
811 views
Is it possible to get arcpy on 9.3* or Qgis? Or maybe some of the functions?
If this isn't possible what would be the closest equivalent open source? Could parts of the module be ported to work on 9.3 or QGIS? I'm not sure if this would infringe on the license porting for 9.3. ...
