Hi Ticker, my concern is that the data in the labels is also used to calculate a height profile when routing is enabled. Maybe this also depends on the --show-profiles option. Gerd ________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Ticker Berkin <rwb-mkgmap@jagit.co.uk> Gesendet: Mittwoch, 11. Oktober 2023 11:51 An: Development list for mkgmap Betreff: Re: [mkgmap-dev] Contour lines without elevation. What shoul mkgmap do? Hi Gerd Looking at the code, there shouldn't be any crash from mkgmap if a contour line doesn't have an "ele" tag. I assume the Garmin device will just draw the appropriate line without a label. This might be common where alternate contours are not given heights. So, no; I don't think you should add any checks. Ticker On Wed, 2023-10-11 at 08:16 +0000, Gerd Petermann wrote:

Hi all,

in a private mail I was informed that mkgmap crashes when polish input contains no label for types which are considered as contour line data like this [POLYLINE] Type=0x20 Data0=(51.5300781,-0.0988259), (51.5305501,-0.0989852), (51.5311576,-0.0992174) [END]

The same data was handled without problem before r4907. As a quick hack I've added a null check to restore the old behaviour, but I wonder if it would be better to stop with an error message or maybe ignore contour line data when no elevation is given in the label?

I guess the same problem can happen with OSM data when a style uses the line types 0x20 .. 0x25 . Should I add checks to warn when these line types are used without a proper label that can be elevation data?

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Ticker Berkin <rwb-mkgmap@jagit.co.uk> writes:

Looking at the code, there shouldn't be any crash from mkgmap if a contour line doesn't have an "ele" tag. I assume the Garmin device will just draw the appropriate line without a label. This might be common where alternate contours are not given heights.

So, no; I don't think you should add any checks.

I'm just barely reading list mail, but I agree with Ticker. A contour line without an elevation still makes sense, at least enough sense that it shouldn't be rejected. However, I don't really grasp Gerd's comment about elevations used for routing. Presumably that is in some newfangled Garmin device that proceses a route with respect to contours? If so, then I see how this is really hard, choosing between: reject accept accept only if some flag is or isn't given, to be set depending on if one is building maps for routing/elevation devices