question about calculating distances

Discussion created by michelle_pop on Oct 30, 2011
Latest reply on Nov 2, 2011 by michelle_pop
Hello everyone,
I created an OD matrix for distances between facilities and population centroids. Neither the facilities nor the centroids are located on the street network, but some distance away (e.g., 50-200 m). When I manually verify the distances I obtained in the OD matrix, I get values that are close, but not identical to the values from the matrix. I am not sure how are these distances being calculated? Are they measured from the point on the network that is nearest to the facility to the point of the network that is nearest to the centroid only? I believe the additional distances to the facilities and centroids (the so called "snapping distances") are not considered, is that right?
My points layer and my street layer are in the same projection.
Thank you!