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I would like to select areas under a particular circular radius in QGis. I believe this is accomplished with the buffer tool, but when I specify the radius the area is not circular. How to make it circular?

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up vote 6 down vote accepted

If you buffer a point, the result will be a circle only as long as you don't re-project the layer.

enter image description here

I guess you have on-thy-fly re-projection enabled. Try turning it off.

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When I turn off 'on the fly' CRS transformation all of my shapefile layers become invisible. Is this what you were referring to? – Robertg Mar 6 '11 at 18:08
They just change their location. Use "zoom to layer extent" to find them again. – underdark Mar 6 '11 at 18:16
I'm using google maps as a layer. When I click zoom to layer my points change in respect of their position on the map. – Robertg Mar 6 '11 at 18:20
The google maps raster layer cannot be reprojected on the fly. If you want circular buffers on top of your Google map, re-project you point vector layer to "Google Mercator" and re-apply the buffer. – underdark Mar 6 '11 at 18:24
I'm not sure how to do that or what it means. Looks like I'm going to have to learn about GIS more thoroughly. – Robertg Mar 6 '11 at 18:31

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