I'm totally new to stackexchange and i'm in this beautiful informative place for one problem. I'm a .net programmer and i need to write a program that reads a shapefile and performs routing operation. I'm looking for an open source solution. Is there any idea?
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Does the shapefile already have from-nodes and to-nodes assigned to it?– Kirk KuykendallCommented Aug 4, 2011 at 15:35
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unfortunately not. Is it possible to make it in ArcGIS?– Saka RoybanCommented Aug 5, 2011 at 13:46
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Are the ends of the polylines snapped to each other? If so you could calculate FNODEID and TNODEID fields based on concatenation of x and y of the polyline's from point and to point respectively. You should also consider an ID for the polyline itself, since the FID could change as a result of editing. Once you have the necessary IDs, you can handle it as a graph theory problem. See resources.– Kirk KuykendallCommented Aug 5, 2011 at 14:17
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yes. How to create these fields in ArcGIs or any other software? Does it need programming? Could u explain more, Plz?– Saka RoybanCommented Aug 5, 2011 at 18:52
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3 Answers
I would start by looking at this implementation in C# along with the DotSpatial libraries maybe?
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It sounds i have to make graphs out of shapefile myself. Am i right? I was looking for a more direct way, not to handle this dirty things. Commented Aug 5, 2011 at 13:55
Small advice: use A* algorithm instead of Dijkstra, with a decent heuristic you'll get much better performance.
https://stackoverflow.com/questions/1332466/how-does-dijkstras-algorithm-and-a-star-compare
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Thanks. but is there any implementation for that in .net using shapefile? Commented Aug 5, 2011 at 13:52
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You should treat reading shapefiles and A* algorithm routing as two separate things. A* is usually implemented in a generic way so it can be reused for different purposes. As for reading shapefiles, take a look at SharpMap. Commented Aug 5, 2011 at 14:16
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If the open source requirement isn't too strict (you already seem to accept Arcgis as part of the solution), you can also look at our RW Net solution (www.routeware.dk). It is a .NET component, which will import SHP files and let you do routing calculations. No need for adding fnode/tnode fields, since the component handles that internally.
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Thanks a lot. Yes, i have arcgis but i can't pay anymore. It Sounds Route Net 2.43 free version performs the job. Also i found TF.Net useful i.e reading shapefile and calculates shortest path, as described in documentation Commented Aug 6, 2011 at 11:25