Working in ArcGIS 10, I have a set of contour lines representing density of commercial square footage, and I have a set of points representing local maxima for each peak of the dataset. For each maximum I would like to find the largest contour line that contains only that maximum and no others.
My strategy is to convert the contours to polygons, spatially join the polygons to the points, choose only the polygons that overlapped 1 point, and for each maximum choose the largest polygon, an operation that will probably happen in MS Access.
I've run into one problem – when I convert the contours to polygons using "feature to polygon", the polygons don't overlap, so my maxima only join to one polygon, breaking the method.
How can I convert polylines to overlapping polygons? If possible, I'd prefer a solution I can fold into an ArcPy script.
Best Answer
You started off with a kernel density grid. Negate it (thereby flipping it upside down) and fill the sinks. Comparing the filled grid with the original will identify all areas of fill: their boundaries are the desired contours.