[mkgmap-dev] Option --dem-profile seems to cause crash in MapSource

Wed Jan 31 17:04:47 GMT 2018

Hi all,

sorry, I wrote
"A work around is to tell splitter that it should use e.g. height 0 for these values:
--x-dem-outside-polygon=0"
Of course this is an (undocumented) mkgmap option, not one for splitter.

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Gerd Petermann <gpetermann_muenchen at hotmail.com>
Gesendet: Mittwoch, 31. Januar 2018 17:55
An: Development list for mkgmap
Betreff: Re: [mkgmap-dev] Option --dem-profile seems to cause crash     in      MapSource

Hi DEM experts,

the problem seems to be the value that is encoded for heights outside of the polygon.
So far mkgmap writes the same value that is used to signal a void in the data.
This seems to cause trouble, maybe even more as I see full rows of such voids.
A work around is to tell splitter that it should use e.g. height 0 for these values:
--x-dem-outside-polygon=0
I don't like this because it creates visible "steps" at the polygon boundary when height switches between
0 and the real value.

I've looked again at the Adria Topo map and it seems that Garmin uses a different approach:
Although tile boundaries are not rectangular the DEM data is filled for the full rectangular area.

My conclusion:
So, either we have an error in the encoder which occurs when it encodes many values with
the max height and this max height is flagged as invalid or Garmin software simply cannot handle
larger areas of voids.

At the moment I have only one solution which is similar to the one in the Adria map:
The polygon from --dem-poly is used for the tile boundaries, not the DEM data.

Attached is the corresponding patch.
A binary is here:
http://files.mkgmap.org.uk/download/409/mkgmap.jar

Note that this only works well when you also use e.g. osmconvert to filter the input data for splitter with the same bounding polygon.
Sample:
osmconvert --drop-author -B=xyz.poly niedersachsen.o5m -o=part.o5m
java -Xmx5G -jar d:\splitter\dist\splitter.jar --output-dir=split part.o5m > splitter.log
java -Xmx5G -jar d:\mkgmp\dist\mkgmap.jar --dem-poly=xyz.poly ... -c -c split\template.args

What do you think?
Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Gerd Petermann <gpetermann_muenchen at hotmail.com>
Gesendet: Mittwoch, 31. Januar 2018 15:23
An: Development list for mkgmap
Betreff: Re: [mkgmap-dev] Option --dem-profile seems to cause crash in  MapSource

Hi all,

some more details:
The problem only appears when a route on the map created with --dem-poly crosses tile boundaries.
It doesn't seem to depend on the route itself, I've tested 5 different routes crossing tile boundaries
and always got a crash when clicking on "Show profile..."
It also does not seem to depend on the style or the existence of additional contour lines.

So, for now I'd say: Don't use --dem-poly

Gerd

________________________________________
Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Gerd Petermann <GPetermann_muenchen at hotmail.com>
Gesendet: Mittwoch, 31. Januar 2018 12:19
An: mkgmap-dev at lists.mkgmap.org.uk
Betreff: [mkgmap-dev] Option --dem-profile seems to cause crash in MapSource

Hi all,

I've just noticed that MapSource crashed after pressing the "Show Profile..." button for a route.
I can reproduce the crash on MapSource, Basecamp just says
"The current map does not contain any elevation data on the selected route(s)"
This problem disappears when I remove the --dem-poly option, so I think there still is a problem
in the encoder :-(
The interesting thing is that my route is far away from the polygon boundary.

I'll try to find out more ...

Gerd
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