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Ensure that your polygons have an area attribute separate from the one that is/may be automatically updated by the software when the shape is edited. Intersect your buffer and polygon layer. In the resulting layer, open the attribute table. If there is a new/correct area field in the same units as the original area field from step 1 you can use that - ...


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The ArcGIS help files for the Buffer tool include a How Buffer Works page with a full description. There, it is explained that offsets are created from the line and its vertices, then connected to form the buffer. But the page also goes into detail about the difference between Euclidean and Geodesic buffering, which comes into play when working in ...


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If you want a conditional buffering based on some attribute, you can use a case statement, eg, SELECT ST_Buffer(geom, CASE WHEN atr = 0 then 10 WHEN atr=1 THEN 20 ELSE 30 END) FROM mypoints; Obviously, you can have as many WHENs as you like, though it could get cumbersome fast. If it is a straight multiplier, then you can just do ST_Buffer(geom, atr * ...


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I was just looking for the same answer myself and while my answer is not 'official', it's based on my interpretation of this Training Manual entry I found: http://docs.qgis.org/2.2/en/docs/training_manual/answers/answers.html#basic-distance-from-high-schools I think the above illustrates the buffer segments quite well. My answer is therefore... The ...


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In the Buffer tool there is no Just Overlapping option, it's all or none. To make the buffers merge where overlapping and nowhere else it's necessary to buffer with dissolve of 'all' and explode the feature using Multipart to Singlepart. Now each cluster of buffers is a single polygon and you can use the spatial join tool to count the number of points in ...


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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


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You can: Make a copy of your dataset into UTM or LCC Change the project CRS to that projection Create the buffer in that projection If necessary, use Dissolve to get a single non-overlapping buffer If necessary, densify the buffer with a factor of 10 or more Save the buffer under another filename and CRS set to NAD83 Remove the UTM/LCC layers Set project ...


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What you are looking for here is the blending effects you can do on the vector features. Example only of course, you can do a lot more with the blending effects. Just play around until you find something that you like.


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For a raster layer: you can create a Heatmap (Raster > Heatmaps) which is quite effective in showing concentration differences (note: available to download and install this from the plugins menu if you don't already have it): I used the following style options for the heatmap raster layer: Hope this helps!


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So, the output data of your model is a single feature class that represents the analysis' results (buffering). After running the model and exploring the results in ArcMap, you are not satisfied with this and want to re-run the model using another input parameters' values (e.g., another buffer distance). The only thing you need is just to allow the model to ...



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