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If you want to compare vector-paths the "Road Graph Plugin" is working fine. If this is interessting for you dont forget to use the "Topology Checker" before analysing the data.


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Convert path to polyline and calculate its length or lengths of the segments in its attribute table by right clicking on one of the empty columns (if there is none add one) and then selecting Calculate Geometry option. Friction costs can be extracted to the new table by using Stack Profile.


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Your Cost Surface could be the problem. The value of the Cost surface cell represents the cost for each map unit, not for the whole cell. The cost-values are multiplied with the resolution when using the cost-distance function.


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Try to use the Identify Tool to make sure there are values existing in your output raster at places where you expect them.


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Your assumption concerning the output values is wrong. The cost-values are multiplied with the distance when using the cost-distance function. Hence 500m equal a cost-distance value of 5,000. I can only guess but I think the 70 may equal the cost-distance value from the center of the green pixel to the next cost-pixel. I see that there are high ...


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Here is some R code. The paper says that they randomly shifted the path. I take that to mean they randomly shifted each node of the path. They say that the path was shifted between 0 and 30 but I think that it only makes sense to shift between -30 and 30. EDIT: taking advantage of center of gravity rotation in the maptools package library(sp) ...



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