GPSMapEdit Map Verification

[babj615]

Recently, I have started to play with adding routing information to my maps using GPSMapEdit:

I will save my map in current configuration (*.mp) and select 'Tools > Verify Map...'. I will get a list of several hundred errors, and I will spend hours correcting each error until the 'Verify Map' process no longer returns a single error. I can then save the map (*.mp) as is, and run the map verification at will, returning zero errors each time.

However, If I re-run the 'Tools > Generate Routing Graph' function, and then re-run the map verification, I will again be presented with hundreds of errors, many of which appear to be duplicates from the previous verification.

After about the third time around, I did not save the new *.mp mapset, and undid ('ctrl-Z') the new routing graph. Now verification result sin zero errors.

Why do all these errors reappear after running the 'Routing Graph Generator' again? I have not changed any data in the map between.

I assume I must run the 'Routing Graph Generator' after any map edits for the map to be exported with complete and accurate routing information.

If any of GPSFileDepots master map makers familiar with this process would be so kind as to offer advice, i would be very grateful!

[Seldom]

Depending on your Verify Map options the Verify Map procedure will check lots of non-routing issues like malformed polygons.  To keep things simple, I usually keep my routable data on a separate map from non-routable, and only verify the routable map after I've generated a routing graph.  I'll combine all my topo, hydro, and wooded areas, generalize and slice them, and save the map.  I'll then "ADD" or paste the routable elements onto this map, and verify the combined map.  The second verification may show some errors with unspecified line types, which GPSmapEdit interprets to be roads.

Slicing non-routable objects greatly reduces compile time.  It can also make malformed polygons really ugly, so I don't slice those.  I also don't slice the routable map.

One other thing.  If you run cgpsmapper with error reporting, it will report a lot of "Node too Close" errors that GPSmapEdit doesn't show.  My experience is that GPSmapEdit is correct, so turn off the stop on error option of cgpsmapper and just do your error checking in GPSmapEdit.

[babj615]

Thank you Seldom, I still have a lot to learn...

I have noticed today, that if I add new transportation polylines to my map, but do not re-generate a new routing graph, when I test the map routing, my new polylines route perfectly.

This leaves me wondering, what is the purpose of generating a routing graph? And when should I do it?

[Seldom]

The routing graph keeps track of the node connections for routable features.  (And adds little colored squares to the map representing those nodes.)  Are you saying that you can add a polyline without regenerating a routing graph, and GPSmapEdit will route from that polyline to one that it joins?  Cause it's not working that way for me.

[babj615]

Yes, Seldom, that is exactly what GPSMapEdit is doing for me! I am aware of the colored squares representing routing nodes, with different colors indicating the number of connections.

I just added several polylines to one of my maps yesterday, some of which were linked to existing polylines, and GPSMapEdit adds the routing nodes to each polyline as I create them.

After adding a dozen or so, I wanted to test them, so I selected one section of a pre-existing polyline as a start point and selected a newly added polyline as an end point, and GPSMapEdit successfully routed old and new lines correctly. I tested in reverse, starting at a new line and ending at old lines, with same results, then only along new lines, and same result.

Update: Just tested the new map on my GPSr, and the new polylines also route properly on the GPSr as well!

I have not performed a new map verification or generated a new routing graph for the current *.img export.

[babj615]

Here is a better explanation of the issue I am having:

I can have a map open in GPSMapEdit, perform a map verification, and get zero errors.

Then I run the Create Routing Graph and verify the map again, and GPSMapEdit return hundreds of failures that were not present before running the Route Graph Generation.

It appears that GPSMapEdit is corrupting the map each time it is run.

Here is a visual example:

[Red90]

I could be wrong, but I believe when you run the generate routing nodes command, it is assuming there is no existing routing nodes, so it adds new ones.  Where you already have nodes, it doubles up.

[babj615]

Thank you Red90.

I tried again by first deleting all routing nodes, saving the map again, and then generating a new routing graph, with identical results.

It appears that GPSMapEdit is actually adding additional routing nodes to each polyline point near existing polyline connections.

I know there is a limit (2.4 meters?) to how close any two routing nodes can be, but does this also apply to any/all polyline shaping points?

[Seldom]

You've got me puzzled, babj615.  I just tried creating some bogus trails on one of my BigDesertSouthwest tiles.  I used the polyline creation tool.  It prompted me to select a road type.  I selected trails and it showed routing nodes on both ends of the line segments.  I then used the "point modify (M) tool" to connect the nodes and they turned from two blue nodes to a single white one.  I tested routing between the segments and it worked.  I then generated a routing graph and it still worked. 

I have never found that generating a routing graph has been destructive, nor has "verify map".  In fact in translating from OSM data to MP, I frequently find roads with "too many nodes".  To eliminate the extra nodes I normally change the road to a non routable object like a power line.  That deletes the nodes.  Then I change the object back to a road and generate a routing graph,  The routing graph connects the ends of the cleaned up road to the road network with no other problems.

[babj615]

Thank you Seldom for the awesome tip on removing excessive routing nodes from polylines. Never occurred to me to change to a non routable type and back again!

I did hear back from the creator of GPSMapEdit, and they have duplicated my issue, and are looking into it.

[Seldom]

Just curious what version of GPSmapEdit are you using?  I'm using 2.0.77.1 and I'm not having that problem.

[babj615]

2.0.77.1 on WIN8.0 x64

[Seldom]

I'm using Win7-64.  I wonder if that's the difference?