[mkgmap-dev] [PATCH] Inter-Tile routing - alpha code for testing

Tue Feb 17 21:43:43 GMT 2009

Hi Robert,

> It's very barely tested: I created two small .mp-files with boundary  
> node data, where some of the boundary nodes were actual junction nodes  
> and some weren't. I loaded the combined gmapsupp.img on my GPS, and  
> routing across tile boundaries worked partially; it seemed to work  
> fine in the vicinity of non-junction boundary nodes. I didn't test  
> this with MapSource.
> 
> A first thing to do to confirm the patch does what it should would be  
> to run two such tiles through test.display.NodDisplay and see if the  
> NOD3-entries are what you'd expect. There should be one per boundary  
> node. (Furthermore, the corresponding entries in NOD1 should have a  
> flag set.)

I have done what you suggested and, at first glance, the NodDisplay
output looks reasonable. Here's a typical NOD1 node:

         |        |                         | New node
00000329 | 0002ea | 1e                      | low 1e
0000032a | 0002eb | 4c                      | Flags 4c
         |        |                         | : boundry-node 
0000032b | 0002ec | 30 0b 11                | longitude 11.20605
         |        |                         | latitude 48.30191
0000032e | 0002ef | 79                      | alt6 byte 79
         |        |                         | newdir 0, extra 38, destclass 1
         |        |                         |   sign true
0000032f | 0002f0 | bd dd                   | last one
         |        |                         | pointer to another node fddd
         |        |                         |  -> node c7
00000331 | 0002f2 | 10                      | pointer to local net index 16
00000332 | 0002f3 | 94 02                   | length 148
00000334 | 0002f5 | 65                      | direction 142 degrees
         |        |                         | ------

I know nothing about this encoding so this may be completely stupid but I
notice that it says 'last one'. I'm guessing that this means it's the last
node in the way but should that be asserted for a boundary node?

Cheers,

Mark