Hi, I have a feature class with about 400 points that are in the ocean. I'm trying to use the network analyst extension to find the shortest route to travel to each point (as the crow flies more or less). I'm having trouble creating my network dataset. I read in another post that I should make a fishnet feature class (of polylines I'm assuming) of the whole area and use that as the roads. I would have to add a land feature class as a sort of barrier. Then I could solve the route with using the reorder option. None of the tutorials I've read have really shown me how to deal with this situation. Could someone please point me in the correct direction for solving this traveling salesman problem? Thanks
Thanks, I've been trying something like that, but haven't nailed it yet. The polygon land barrier is needed because these points stretch from Gulf of Maine to the Carolinas and when I did a nearest neighbor route (calculating the closest point, drawing a line to it, then removing it from the list), I would get lines running from Jersey across Cape Cod over land. And unfortunately, our ship can't fly 🙂
-Now it asks me if I want to model turns in this network. I'm not exactly sure what that means in my context. Would the turns be the paths across the polyline fishnet? What should I put here? If yes, are the turn sources just the default global turns?
Next menu is connectivity. When I click that and the connectivity groups show up, what options do I take? Do I set the connectivity policy to end point or any vertex? There is another column with a "1" and a check box under it. Do I check that or not?
The next menu asks to specify the attributes for the network dataset. A row with the name Length is there with cost for usage. Do I need to add any parameters or change anything under the evaluators button and menu?
If I use just end points, doesn't that turn each line in a a street with no turns off of it? Meaning if I wanted to travel 100 meters east to a parallel street and I was on a north/south street, I would have to travel all the way to the end and turn twice? I don't think I am explaining that well, but I thought each overlap in this case would be a 4 way intersection so that diagonal lines could be traveled upon.
I created the data with your help and if it is correct, then how I solve the problem is the issue. What I do is add the newly built network dataset to my map when prompted and make sure it is selected in the drop down in the network analyst toolbar. Then (in the toolbar) I then click network analyst-->new route. Then I click the create network location tool and add new points which are entered in as stops. When I click the solve button I get this message every time (and I've tried different locations in the network with different numbers of points and it is always the same):
Warning: No route from location "Graphic Pick 1" to location "Graphic Pick 2".
Error: No solution found.