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i am trying to map archaeological finds with qgis. some of them have the same coordinates since they are from the same site or very close to each other. is it possible to automatically display the number of finds in a close range through a varying size of the symbol? so, the more datapairs i have in the same spot, the bigger the symbol gets? otherwise 10 finds just appear as one in the map because they are kind of on top of each other...

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3 Answers 3

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You can use the 'Point displacement' renderer for your point layer. Get the Layer Properties window up, click on the Styles tab and select Point Displacement from the drop-down list.

See image below for an example: enter image description here

There are a few options you can tinker with but basically you end up with concentric rings radiating from the common location (in this example a red dot):

enter image description here

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yeah, that's it :) if i change the size of the radius and the dots accordingly it ends up like something i imagined - thank you and everyone else for the creative advice :) –  user16891 Apr 7 '13 at 9:25

Is not exactly what you ask for, but i think that a heatmap is good choice for your case.

qgis has a heatmap plugin that can helps you.

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thanks, i am going to try this, seems like there is no such thing as an "easy solution" for this ...although i have seen a lot of those kind of maps so i am wondering how others did it... –  user16891 Apr 6 '13 at 22:09

One approach could be to create a polygon grid over your area of interest, with the grid cell size matching what you consider "close range" so that each site is covered by one cell. THis you can do with the "Vector grid" option under "Reasech tools". Then use the Points in Poly tool under "Analysis tools" to get a count of points in each polygon grid cell. Now stylize the polygon cells with a color ramp based on the PNTCNT attribute. HTH

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thank you, but i want to still have the background map and lanscape features visible, they would be hidden that way, wouldn't they? i actually really just want to make the points that "hide" each other (the ones that are exactly on top of each other/very close) visible... –  user16891 Apr 6 '13 at 22:12

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