Tag Info

Hot answers tagged

4

Running the buffer tool will create a second polygon offset the distance you specify from the first. Corners are radiused by default, no need to crop.


2

This can be accomplished with an Intersect, followed by a Field Calculate, and then finally a Summary Statistics. Make sure that your buffer feature class has a unique ID field. Before getting started, you will need to add a field (name Polygon_Areas, type Double) to your population polygon feature class, and then field calculate it, using Shape_Area as the ...


1

I realized I needed to set the coordinate system of shp to WGS84, then write out to a new file and specify the local coordinate system - then add that layer to the map and buffer it. Worked! Here is my updated code: from qgis.core import * from qgis.analysis import * from PyQt4.QtCore import * from PyQt4.QtGui import QInputDialog from qgis.utils import ...


1

Try using the Near (analysis) tool. The resulting table will show which point is closest by whatever OBJECTID you specify. Then perform a join and field calculate the values into your previous points.


1

If you have the spatial analyst extension you can use the Euclidean Distance tool. 1. Convert the buffer to a raster with the "To Raster" tool (under conversion tools). 2. Then run the Euclidean Distance Tool which will create a raster with values representing distance from the cells that comprised the input raster. 3. Then if necessary, you can extract ...


1

you will NOT have the same results, but both results have their own interest. In the first case, the buffers will not overlap. So the total area under the multiple ring buffer will be equal to the area of one large buffer. This is usefull if you want categories of distances (e.g. how many inhabitants are between 1 and 2 km away from an hazard). Note that, ...


1

Here's a blog post by Paul Ramsey about doing this in PostGIS, perhaps a worthy venture: http://boundlessgeo.com/2014/10/postgis-training-creating-overlays/ Summed up with this note: Now we have a single coverage of the area, where each polygon knows how much overlap contributed to it. Ironically, when visualized using the coverage count as a ...


1

You could use the Intersect tool (Vector > Geoprocessing Tools > Intersect) on the buffers and then to find the number of intersections it would simply be the total number of attributes - the number of points.


1

I guess that the projection you used is the problem. As far as I am aware off, thr QGIS (I'm using 2.8.1 - but it should be the same) buffer tool use the default measurement of layers coordinate system, thus degrees, not meters. So 500 meters, is actually being treated as 500 degrees - this can explain your outputs. What you can do, is either project your ...


1

There are a couple ways to accomplish this task. The first is the Summary Statistics, as I explained in your other question. A second way to do this is to first perform your Intersect, and proceed this with a Dissolve, with the buffer unique ID field as your Dissolve field. This creates a new feature class with each feature representing all ...


1

If I understand you correctly I think you are looking for the clip tool. in ArcGIS 10 and above it should be in geoprocessing → clip (or in toolbox Toolboxes\System Toolboxes\Analysis Tools.tbx\Extract\Clip) your input would be the parks and the clip feature would be the buffer. this will create a new feature class that is only the parts of the parks that ...


1

The Measure area tool does not create a layer which can be input for Processing. You need to create a new polygon layer, for example a Memory layer, see http://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/vector.html#memory-provider and Using in-memory vector layer with QGIS processing / SEXTANTE


1

Wonder why don't you use ArcGIS's expand tool? import arcpy from arcpy.sa import * raster_in = r'c:\test.tif' raster_out = r'c:\test_out.tif' outExpand1 = Expand(raster_in, 2, 2) outExpand2 = Expand(outExpand1, 3, 3) outExpand3 = Expand(outExpand3, 4, 4) outExpand4 = Expand(outExpand4, 5, 5) outExpand4.save(raster_out) In case of overlaping: the ...



Only top voted, non community-wiki answers of a minimum length are eligible