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I am building a model to generate two zones around a point, a 250m-buffer, and a ring of 250 to 1000m, where i recalculate values from an other layer according to the intersections share.

The purpose is to examine if values in the 1. buffer are smaller than in the second. The rest of explanations would take too long and everything goes fine so far.

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The final step would now be, to sum up the values for each layer, but somehow I can't find a solution.

There is the "Statistics by categories" function in the modeler which produces a stats-table i could join back to my layers and then dissolve them, but ... for whatever reason ... this only produces values for min, max, mean and stddev, but no sum of values!!

All dissolve functions available, do not offer any summing or whatever actions.

Anyone got any idea?

I'm stuck 1 meter in front of the finish line ...

P.s: there is NO option to do anything manually there. Simply too many points with too many other parameters to check each time. Thats why I made the model ...

UPDATE: Now I had the ideas to create centroids from all intersected polygons and then do a SAGA Points in Polygon statistic (which includes a SUM !!!!) with the un-intersected buffer a few steps before ... but this time the SAGA function is buggy and doesn't work.

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If I understand it correctly you are looking for something like the grass command "v_vect.stats" (which is not available in the modeler of QGIS2.2). But to solve your problem you could use the "Count points in polygon" geoalgorithm in the modeler. You can multiply the number of points per polygon with the mean value per polygon to get the sum of all points per polygon.

  • Thanx for your answer. No, I fear you didn't get it. I simply would need a summed up value for of the numbers shown in the yellow and in the green area. Have't tryied if there were any changes in processing for that since october, but by then, there was no function to do this which worked. Some functions didn't offer any summing and the others crashed due to bugs I think. – Bernd V. Apr 8 '14 at 0:53

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