[mkgmap-dev] The "Elevation=M" in the header of the polish .MP files does not work

Mon Mar 6 13:24:42 GMT 2023

Hi all,

Thanks a lot for the new build r4907 !!!
It works well.

But there are problems with the accuracy of the values.
Often integers are converted to fractions.
Perhaps something with rounding of intermediate fractional values.

(.MP)->(.IMG) in meters:
22 -> 21.9 (-0.1)
22.5->22.6 (+0.1)
23->22.9 (-0.1)
23.5->23.5 (=0)
24->24.1 (+0.1)
24.5->24.4 (-0.1)
25->25 (=0)
25.5->25.6 (+0.1)
26->25.9 (-0.1)
26.5->26.5 (=0)
27->27.1 (+0.1)
...
Can accuracy be improved?

PS: Values of CONTOUR types 0x10900...0x10905 are still not converted according to the ELEVATION=M parameter. :(
PPS: It is worth noting that cGPSmapper has the same problems…
--
Vadim
>
>Суббота, 4 марта 2023, 11:23 +03:00 от Gerd Petermann <gpetermann_muenchen at hotmail.com>:
> 
>Hi Vadim,
>
>the code in mkgmap seems to expect int values when elevation is given in m. No idea why, the code is from 2008 and wasn't changed since:
>
>        private void fixElevation() {
>                if (elevUnits == 'm') {
>                        String h = polyline.getName();
>                        try {
>                                // Convert to feet.
>                                int n = Integer.parseInt(h);
>                                n *= METERS_TO_FEET;
>                                polyline.setName(String.valueOf(n));
>
>                        } catch (NumberFormatException e) {
>                                // OK it wasn't a number, leave it alone
>                        }
>                }
>        }
>
>I can change that to use double precision but you probably need more changes to support the special types. Maybe you can modify PolishMapDataSource.java
>and provide a patch?
>
>Gerd
>
>
>________________________________________
>Von: mkgmap-dev < mkgmap-dev-bounces at lists.mkgmap.org.uk > im Auftrag von Vadim Karpov < bombur at mail.ru >
>Gesendet: Freitag, 3. März 2023 09:46
>An: Development list for mkgmap
>Betreff: Re: [mkgmap-dev] The "Elevation=M" in the header of the polish .MP files does not work
>
>Hi all!
>
>Thanks for the new build (r4906) !
>But the problem is only partially solved.
>
>Integer values (22 or 12) are converted normally.
>But fractional ones (for example: 25.5 or 26.25) are still perceived by the compiler as feet. :(
>
>All values of subtypes 0-5 of marine type 09 (0x10900 … 0x10905) are interpreted exclusively as feet...
>
>PS: I can't place an example .MP file in this mailing list. I will send it personally.
>Четверг, 2 марта 2023, 18:01 +03:00 от Gerd Petermann < gpetermann_muenchen at hotmail.com >:
>
>Hi all,
>
>OK, I see no problems to change this method in GType.java:
>        public static boolean isContourLine(MapLine line) {
>                return line.getType() >= 0x20 && line.getType() <= 0x22 && !(line instanceof MapShape);
>        }
>
>All I have to do is to change 0x22 to 0x25, right?
>
>Gerd
>
>________________________________________
>Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk< /compose?To=mkgmap%2ddev%2dbounces at lists.mkgmap.org.uk >> im Auftrag von Vadim Karpov <bombur at mail.ru< /compose?To=bombur at mail.ru >>
>Gesendet: Donnerstag, 2. März 2023 14:38
>An: mkgmap-dev at lists.mkgmap.org.uk< /compose?To=mkgmap%2ddev at lists.mkgmap.org.uk >
>Betreff: Re: [mkgmap-dev] The "Elevation=M" in the header of the polish .MP files does not work
>
>Hi
>
>Yes.
>
>Types 0x23.0x24.0x25 are used to create bathymetric maps.
>
>Information from the MPCTypes.txt file (TypViewer application):
>
>0x02000=Contour Lines/MINOR_CONTOUR/Minor land-based contour line/Non NT
>0x02100=Contour Lines/INT_CONTOUR/Intermediate contour (should be used for about every 5th contour line)/Non NT
>0x02200=Contour Lines/MAJOR_CONTOUR/Major contour (should be used for about every 10th contour line)/Non NT
>
>0x02300=Contour Lines/MINOR_BATHY_CONTOUR/Minor bathymetric, or depth, contour/Non NT
>0x02400=Contour Lines/INT_BATHY_CONTOUR/Intermediate bathymetric, or depth, contour (should be used for about every 5th contour line)/Non NT
>0x02500=Contour Lines/MAJOR_BATHY_CONTOUR/Major bathymetric, or depth, contour (should be used for about every 10th contour line)/Non NT
>
>Четверг, 2 марта 2023, 12:01 +03:00 от Ticker Berkin <rwb-mkgmap at jagit.co.uk< /compose?To=rwb%2dmkgmap at jagit.co.uk >>:
>
>Hi
>
>My understanding of the default Garmin usage is that
> 0x20..0x22 are land/height contours (Minor to Major)
> 0x23..0x25 are sea/depth " "
>
>Ticker
>
>On Thu, 2023-03-02 at 08:52 +0000, Gerd Petermann wrote:
>> Hi Vadim,
>>
>> I see code in mkgmap to handle the statement with Elevation=m or
>> Elevation=M, but it is only used for the line types 0x20 .. 0x22.
>> Do you have a good reason to use line type 0x25 instead?
>>
>> Gerd
>>
>>
>> ________________________________________
>> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk</compose?To=mkgmap%2ddev%2dbounces at lists.mkgmap.org.uk< /compose?To=%2fcompose%3fTo%3dmkgmap%252ddev%252dbounces at lists.mkgmap.org.uk >>> im Auftrag
>> von Vadim Karpov <bombur at mail.ru</compose?To=bombur at mail.ru< /compose?To=%2fcompose%3fTo%3dbombur at mail.ru >>>
>> Gesendet: Mittwoch, 1. März 2023 13:00
>> An: mkgmap-dev at lists.mkgmap.org.uk</compose?To=mkgmap%2ddev at lists.mkgmap.org.uk< /compose?To=%2fcompose%3fTo%3dmkgmap%252ddev at lists.mkgmap.org.uk >>
>> Betreff: [mkgmap-dev] The "Elevation=M" in the header of the polish
>> .MP files does not work
>>
>> Good afternoon !
>>
>> I am using the latest version of MkGMap and trying to create a depth
>> chart with isolines (types 0x24, 0x25).
>>
>> The problem is that the compiler interprets the depth specified in
>> Meters as in Feet.
>> The result is independent of the presence or value of the
>> "Elevation=M" parameter.
>>
>> And I didn't find an alternative command line option. :(
>>
>> So how can I tell the compiler to treat all numerical depth and
>> height values in an .MP file as meters and not feet?
>>
>> Thanks for the advice.
>>
>> PS: cGpsMapper works fine with "Elevation=M" of course.
>> PPS: Example of polylyne defs:
>>
>> [POLYLINE]
>> Type=0x02500
>> Label=21
>> EndLevel=3
>> Data0=(47.139263517000003,-122.560520313), ...
>> [END]
>>
>> [POLYLINE]
>> Type=0x02500
>> Label=12
>> EndLevel=3
>> Data0=(47.127846400000003,-122.562501059), ...
>> [END]
>>
>> --
>> Vadim Karpov
>> _______________________________________________
>> mkgmap-dev mailing list
>> mkgmap-dev at lists.mkgmap.org.uk</compose?To=mkgmap%2ddev at lists.mkgmap.org.uk< /compose?To=%2fcompose%3fTo%3dmkgmap%252ddev at lists.mkgmap.org.uk >>
>>  https://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>
>--
>Vadim Karpov
>Отправлено из Почты Mail.ru<https://trk.mail.ru/c/zzm979>
>
>--
>Vadim Karpov

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