[mkgmap-dev] Could mkgmap be extended to create an empty dem dist layer?

Fri Apr 20 20:49:06 BST 2018

I've played around a lot with different values - and it behaves very
strange.
e.g. 39768,53024 --x-dem-empty-dist=106048 does not work - no DEM shown at
all.
--dem-dists=39768 --x-dem-empty-dist=106048 - shows dem at 8-15km - at 20km
then the Basemap DEM will be used instead. But at 5km where it's most
important no DEM shown.

I kinda guess there is some pointer we are missing here in mkgmap that is
not about the 0m DEM at all, but about the thing as a whole. It's really
hard to find any kind of pattern that shows with resolution DEM is taken at
which zoom level - it seems to me e.g.  39768,53024,106048 - the first
39768 will be taken for all zoom levels - while producing e.g.  53024,106048
without x-dem the dem will never be used, however dem is shown if I a some
x-dem value.
Also sometimes I manged to brick my Oregon 600 to such a state that even
without the mSD with maps inside it would not boot anymore - it got stuck
on the first  message "Oregon 600 - Copyright 2017" and not make it to the
next steps of loading photos, then loading maps.. Had to start it via USB,
switch off, then  it booted now with the maps on mSD. Actually that
happened to me also without the x-dem option when I tried different
dem-dists. Maybe it's only safe to first remove the old dem gmapssupp.img,
boot, shut down, then insert a new dem only gmapsupp.img - or not use the
same name if you change it?

On 18 April 2018 at 21:46, Felix Hartmann <extremecarver at gmail.com> wrote:

> Thanks a lot Gerd,
> I hope I find soon some time to try it out on my devices (etrex 30, oregon
> 600)
>
> On 18 April 2018 at 09:33, Gerd Petermann <gpetermann_muenchen at hotmail.com
> > wrote:
>
>> Hi Felix,
>>
>> attached is a patch that implements option --x-dem-empty-dist as
>> discussed.
>> I tried with
>> --dem-dists=19884,39768,53024,106048  --x-dem-empty-dist=212096
>> and found no visual effect, and with
>> --dem-dists=19884,39768,53024  --x-dem-empty-dist= 106048
>> the hill shading didn't work at all, and my Oregon froze when I tried to
>> show the elevation data for a route.
>>
>> So, I've also tried with a different patch that writes height 0 instead
>> of "undefined". This seems to work,
>> but I am not sure if it shows the wanted effect. I've attached this 2nd
>> version.
>> Please try on your own.
>>
>> Gerd
>>
>> ________________________________________
>> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von
>> Felix Hartmann <extremecarver at gmail.com>
>> Gesendet: Dienstag, 17. April 2018 12:59:41
>> An: Development list for mkgmap
>> Betreff: Re: [mkgmap-dev] Could mkgmap be extended to create an empty
>> dem       dist layer?
>>
>> I prefer to have Basemap - but I know many people delete it by accident
>> or don't activate it - and I just tried a gmapsupp DEM map will also give
>> shading to overview map.
>> And yeah - maybe call it
>> --dem-empty-dist
>>
>> so you would have e.g.
>> --dem-dists=19884,39768,53024,106048  --dem-empty-dist=212096
>> or
>> --dem-dists=19884,39768,53024  --dem-empty-dist= 106048
>>
>>
>> not sure what values will work best. And yes I would expect only uknown
>> or undefined heights should do the trick - but of course I do not know.
>> With garmins usual approach i do guess it's possible to create it in a way
>> that it switches off at some zoom level by inserting empty data.
>>
>> On 17 April 2018 at 12:40, Gerd Petermann <gpetermann_muenchen at hotmail.c
>> om<mailto:gpetermann_muenchen at hotmail.com>> wrote:
>> Hi Felix,
>>
>> it should be easy to add an empty layer, but I'd prefer a special option
>> for that.
>> Any ideas for a good option name?
>> I guess an empty layer would be one that contains only "unknown" or
>> "undefined" heights.
>> No idea what the device will do with such a layer, I'll try it.
>> If I got you right you prefer to have no basemap on your device? Or maybe
>> some devices don't have
>> one by default?
>>
>> Gerd
>>
>> ________________________________________
>> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk<mailto:
>> mkgmap-dev-bounces at lists.mkgmap.org.uk>> im Auftrag von Felix Hartmann <
>> extremecarver at gmail.com<mailto:extremecarver at gmail.com>>
>> Gesendet: Dienstag, 17. April 2018 11:50:42
>> An: Development list for mkgmap
>> Betreff: [mkgmap-dev] Could mkgmap be extended to create an empty dem
>> dist      layer?
>>
>> If compiling DEM gmapsupp.img for device, right now it will show forever
>> when zooming out - it would be good to have a fake/empty dem top layer - say
>> --dem-dists=19884,39768,53024,212096
>> with 212096 being empty or just having enough data that the device is not
>> actually shading the map?
>>
>> Basically I think dem on device is only useful from around 5-30km zoom
>> levels (with default detail level). 5km is the lowest that the devices
>> choose if DEM is on auto zoom level, but it will continue showing it
>> indefinitely (at least if no basemap is activated) - so getting the device
>> to show an empty dem to switch of shading would be pretty useful.
>>
>> Greetings
>> Felix
>>
>> --
>> Felix Hartman - Openmtbmap.org & VeloMap.org
>> Schusterbergweg 32/8
>> 6020 Innsbruck
>> Austria - Österreich
>> _______________________________________________
>> mkgmap-dev mailing list
>> mkgmap-dev at lists.mkgmap.org.uk<mailto:mkgmap-dev at lists.mkgmap.org.uk>
>> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>>
>>
>>
>> --
>> Felix Hartman - Openmtbmap.org & VeloMap.org
>> Schusterbergweg 32/8
>> 6020 Innsbruck
>> Austria - Österreich
>>
>> _______________________________________________
>> mkgmap-dev mailing list
>> mkgmap-dev at lists.mkgmap.org.uk
>> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>>
>
>
>
> --
> Felix Hartman - Openmtbmap.org & VeloMap.org
> Schusterbergweg 32/8
> 6020 Innsbruck
> Austria - Österreich
>

-- 
Felix Hartman - Openmtbmap.org & VeloMap.org
Schusterbergweg 32/8
6020 Innsbruck
Austria - Österreich
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