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If you are interested in an implementation look at jsts a Javascript implementation of the much used Java Topology Suite library -- depending on whether you prefer reading Javascript or Java, I suppose. A general idea of how the algorithm works. For points, it is trivial, you simply buffer them by a given radius. If you have multiple points, you will have ...


4

If you use the v.buffer tool in the Grass Commands toolsets, you can make a flat buffer. There there are two choice boxes If you have Make outside corners straight set to No, and Don't make caps at the ends of polylines as Yes, the result should be similar to the ArcMap straight edge buffer. The following are the 3 combinations of the above two ...


3

You have to use a projected CRS like UTM (for your part of the world) to get real circles and meters as units. Please do not use Google/Web Mercator, it does not use real meters as units (only at the aequator).


2

You can create square and rectangular grids using the Vector Grid tool under Vector > Research Tools > Vector Grid. To get the required coordinates, I suggest using the Coordinate Capture tool and then input the Xmin, Xmax, Ymin, Ymax from these captured points. Note that the units will be in the coordinate system currently used, so you might want to ...


2

I don't think using Intersect is a good idea as you only have uploaded 1 point file. If you had a line layer with the roads involved, you could very easily intersect the buffers with the roads. An alternative may be to use a Query (Layer > Query...) to filter out the buffers you desire based on the Severity Index. Use something like: "VL_GRAVIDA" >= 20 ...


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I figured it out, FYI, or rather I found the answer on ESRI help page: http://resources.arcgis.com/en/help/main/10.1/index.html#//01m60000002w000000 Clip the inner buffer in an editing session rather than with the Clip tool.


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Choose a suitable UTM grid for your area (see https://de.wikipedia.org/wiki/UTM-Koordinatensystem#mediaviewer/File:LA2-Europe-UTM-zones.png ), probably 32 or 33 (north). Save your layer in the chosen UTM coordinate system. Use the buffer tool on the new UTM layer.


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In my MPSuperShape product, it is possible to apply a buffer to a convex polygon. This is performed by moving the vertices outwards on the line that bisects the two edges at that vertex. The distance is chosen using trigonometry so that the edges both move out a user-specified distance. This works well but acute vertices can extend disproportionately. Ie. ...


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You shouldn't need to re-implement the wheel, there are lots of geospatial libraries out there. As you've noticed, PostGIS includes a buffer function, unfortunately MySQL has sub-standard spatial support and therefore doesn't include one. If possible you may wish to consider switching to PostGIS if spatial functionality is important to you. There are ...



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