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Have a look here:

Hi folks, I think there would be a simple geodetic solution for my question, but let's see: I want to get the direction like on a compass between 0° and 360° between two polar coordinates. How does this work? for example: r_1 = 4.47 theta_1 = 63.4 r_2 = 6.32 theta_2 = 71.6 For the result it does not matter if north or south, nor if it's 90° or 270°, only the absolute value is relevant. Cartesian coordinates unfortunately dont work in case if points are vertically aligned (infinite slope). Regards

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Thanks! I'll have a look on it.

Hi all, I need some help with python code and buffer in ArcGIS: A set of polygons (all in one featureclass, circular shapes) should get several buffers (e.g. 40 times). Each feature gets a different buffer distance, it is stored in corresponding field in attribute table. So the first buffer distance is taken from value in table, the following are calculated by "buffer*i", "i" is counting from 1 to 40. For example: If first feature has the value 400 metres, first buffer for that feature would be 400 metres, 2nd 800 metres, 3rd 1200 metres,.... (measured from the origin shape). I had two attempts, both are not working the way I like: import arcpy arcpy.env.workspace = r"R:\Base.gdb" fc = "export" fieldname = "Buffer" i = 1 while i <= 40: outName = fc+"_" + str(i) dist = (fieldname)*i arcpy.Buffer_analysis(fc, outName, dist) i = i+1 Result: First Buffer OK, then abortion, because cannot find fieldname "BufferBuffer" (sure, multiplication of fieldname, but how to calculate with value and not with the name?). import arcpy arcpy.env.workspace = r"R:\Base.gdb" fc = "export" fieldname = "Buffer" cursor = arcpy.SearchCursor(fc) row = cursor.next() i = 1 while i <= 40: outName = fc+"_" + str(i) dist = row.getValue(fieldname)*i arcpy.Buffer_analysis(fc, outName, dist) i = i+1 Result: No Abortion, but all buffers are calculated based on one value from first feature in attribute table, not the corresponding. In case of using QGis, there are some plugins for multiple buffer, but they work just with static values. Maybe it's just a short fix in code, who could help me?

@rahmansunbeam the worklfow/code of OpenCV seems to be clear, I have to try wheather I get complex shape/geometry into code. However I could get eCogntion to run on my machine. Do you think it would be easier using it rather than the open source examples mentioned here? @hariasa also sounds like a good piece of software but as you say nowhere available, hope the authors will send me an attachment. @yousef2233 I guess your proposal is to be interpreted like pseudo code?

Thanks for reply ! Didn't know about Orfeo. I have experimented a little bit with its feature "Connected Component Segmentation", but no usable results so far. I guess eCognition is for raster analysis only? Since my data is available in shape format I hope to cope without making a detour via raster conversion. One simple method to figure out whether shape differs from an ideal circle is to use the Shape-Index (by Forman and Godron 1986). It indicates the relation between area and perimeter and is standardized in terms of size of area (only for theory, doesn't help at the moment): SHAPE = p / (2*sqrt(pi*a)), where p = perimeter and a = area; SHAPE >= 1, increasing values are less "compact" (this formula is related to vector data, raster formula differs from it, also see hxxp://www.umass.edu/landeco/research/fragstats/documents/Metrics/Shape%20Metrics/Metrics/P8%20-%20SHAPE.htm). Another idea could be to split polygons into lines and analyze length of parallel lines or the amount of angles inside a polygon, but I don't know how.

Hi, how do I classify polygons by shape or geometry? So that similar shapes are automatically recognized and classified. I thought about using landscape metrics, but I dont want to convert to raster. Available software: ArcInfo and QGIS. Here is an illustration of the "process":

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Why not geocoding your postcodes? If there is a database for your country, you will get back lat/lon-coordinates. http://www.gpsvisualizer.com/geocoding.html

Hi, do you know how to replace raster values form a second raster file with different extent? Software: ArcGIS 10.2.2 I've tried raster calculator, but then new raster will only have size for that area, where pixel have been replaced.

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