10 questions linked to/from Calculating roundness/compactness of polygon?
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### Measuring roundness using buffers around centroids [duplicate]

I'm trying to measure the compactness (roundness) of some 800 polygons of different shape and size. I created the centroids and what I want to do now is to buffer those centroids with the exact same ...
• 145
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### Calculating maximum distance within polygon in x-direction (east-west direction) in PostGIS?

I am interested in the maximum width of a polygon e.g. a lake, in east-west direction. Bounding boxes will help only in simple polygons but not in complex concave polygons.
• 141
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### Creating polygons as % of original area using ArcGIS Desktop?

I have a polygon shapefile and need to create new polygons, within the originals, as % of original area. I used buffer by field (Field= new area as %) but the buffers are created in circles around ...
• 81
409 views

### Is there any way to differentiate and select polygons according to their shape on SpatiaLite/PostGIS?

I have this small SpatiaLite database and it looks like the following: It's made of polygons and I'd like to find a way of excluding all polygons that look more like a line. Something like excluding ...
• 1,241
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### Detecting branched polygon shape?

I have a vector layer with millions of polygons making continuous coverage. I need to classify them according to their shape. I am already using several shape indexes from landscape ecology like ...
• 2,481
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### Determine roundness of polygon in QGIS

Suppose a polygon layer in QGIS with differently shaped polygons (no multi-geometries, let's keep it simple). Is there a way to calculate some kind of roundness characteristic of the individual ...
• 505
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### Decreasing polygon size based on percentage using ArcPy?

I would like to decrease the size of polygons by percentage and not by distance in order to implement this into ModelBuilder to loop over a number of polygons. To my knowledge this tool is available ...
• 67
322 views

### Georeferencing a large set of points

I have a static image of a map: And I would like to obtain the coordinates of each blue point. I am very new to QGIS but I have done a very similar task but for a much smaller set of point. My ...
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