[mkgmap-dev] Contour lines without elevation. What shoul mkgmap do?

Wed Oct 11 11:38:23 BST 2023

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 at lists.mkgmap.org.uk> im Auftrag von Ticker Berkin <rwb-mkgmap at 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?
>
> Gerd
> _______________________________________________
> mkgmap-dev mailing list
> mkgmap-dev at lists.mkgmap.org.uk
> https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev

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