[mkgmap-dev] DEM File Format and mkgmap

Mon Dec 18 15:42:33 GMT 2017

Andreas, I have the same issue with some of my pcs  and put it down to 
the capabilities of the pc's graphics card - but I could be wrong


On 18/12/2017 15:37, Carlos Dávila wrote:
> I have generated Italy map with DEM. Hillshading is correctly 
> displayed, but 3D option is disabled in BaseCamp.
> BuildDEMFile command for map tiles was:
> for i in 551${FID}* ; do wine ../../../../dist/BuildDEMFile.exe -O 
> --usedummydata=true -d ${i}/${i}.DEM --hgtpath=../../../../DEM/hgt/ 
> --tre=${i}/${i}.TRE --dlon=0.00027761 --dlon=0.00049 --dlon=0.00075 
> --dlon=0.00106 --dlon=0.0017; done
> And for overview map:
> BuildDEMFile.exe -O --usedummydata=true -d 
> $ABR-1${FID}/551${FID}000.DEM --hgtpath=../../../../DEM/hgt/ 
> --tre=$ABR-1${FID}/551${FID}000.TRE --dlon=0.005
> My options file contains the following levels:
> levels = 0:24, 1:22, 2:21, 3:20, 4:18
> overview-levels = 5:17, 6:16, 7:15, 8:14, 9:12
> Any idea why 3D doesn't work in BaseCamp?
>
> El 16/12/17 a las 14:05, andreas.schmidt.hetschbach at t-online.de escribió:
>>
>> Thx for the hints, but the Problem was I myself. The 3d-view is only 
>> avaiable for the actual Position, i.e. you must have a dem-capable 
>> map installed for the actual position – this works now for me too.
>>
>> Gesendet von Mail <https://go.microsoft.com/fwlink/?LinkId=550986> 
>> für Windows 10
>>
>> *Von: *osm at pinns <mailto:osm at pinns.co.uk>
>> *Gesendet: *Samstag, 16. Dezember 2017 13:15
>> *An: *mkgmap-dev at lists.mkgmap.org.uk 
>> <mailto:mkgmap-dev at lists.mkgmap.org.uk>
>> *Betreff: *Re: [mkgmap-dev] DEM File Format and mkgmap
>>
>> If you are having problems with dem not showing for 1 level then it 
>> may be due to you  not using
>>
>> --usedummydata=true
>>
>> I find this is essential else indeed it produces dem files which have 
>> no effect at all !
>>
>> I also have
>>
>> --lastcolstd --overwrite=true
>>
>> On 16/12/2017 12:04, andreas.schmidt.hetschbach at t-online.de wrote:
>>>
>>> …I´m not too sure how this works at all 😊.
>>>
>>> But what is (if there is one at all) the relation of the number of 
>>> dlon-parameters and the so called Levels? I´ve found out that with 
>>> only one dlon-parameter even the hiillshadung doens´t work. So I 
>>> choosed the same numbers of Parameters as there are Levels in 
>>> Options-file
>>>
>>> Options-file:
>>>
>>> levels = 0:24, 1:23, 2:22, 3:21, 4:20, 5:19
>>>
>>> overview-levels = 6:17,7:14
>>>
>>> BuildDEMFile.exe:
>>>
>>>         C:\Garmin\bin\BuildDEMFile.exe -O -d %%i\%%i.DEM 
>>> --hgtpath=%hgtpath% --tre=%%i\%%i.TRE --dlon=0.00027761 
>>> --dlon=0.00049 --dlon=0.00075 --dlon=0.00106 --dlon=0.0017 
>>> --dlon=0.0025
>>>
>>> Is this correct?
>>>
>>> Gesendet von Mail <https://go.microsoft.com/fwlink/?LinkId=550986> 
>>> für Windows 10
>>>
>>> *Von: *osm at pinns <mailto:osm at pinns.co.uk>
>>> *Gesendet: *Samstag, 16. Dezember 2017 12:35
>>> *An: *mkgmap-dev at lists.mkgmap.org.uk 
>>> <mailto:mkgmap-dev at lists.mkgmap.org.uk>
>>> *Betreff: *Re: [mkgmap-dev] DEM File Format and mkgmap
>>>
>>> Interestingly I don't get the error message.
>>>
>>> I click on 3d View (available on oregons but not GPS64)
>>>
>>> then get this
>>>
>>> http://files.mkgmap.org.uk/download/373/oregon6003dview.jpg
>>>
>>>
>>> On 16/12/2017 10:12, andreas.schmidt.hetschbach at t-online.de wrote:
>>>>
>>>> HI,
>>>>
>>>> not sure if we meant the same thing:
>>>>
>>>> Map displayed with hillshading (Looks ok):
>>>>
>>>>   * 
>>>> http://files.mkgmap.org.uk/download/370/2017-12-16_10-57-56_194.jpeg
>>>>
>>>>
>>>> Menu item 3d-view
>>>>
>>>>   * 
>>>> http://files.mkgmap.org.uk/download/371/2017-12-16_10-58-44_277.jpeg
>>>>
>>>> Error
>>>>
>>>>   * 
>>>> http://files.mkgmap.org.uk/download/372/2017-12-16_10-58-56_743.jpeg
>>>>
>>>> Regards
>>>>
>>>> Andreas
>>>>
>>>> Gesendet von Mail <https://go.microsoft.com/fwlink/?LinkId=550986> 
>>>> für Windows 10
>>>>
>>>> *Von: *osm at pinns <mailto:osm at pinns.co.uk>
>>>> *Gesendet: *Freitag, 15. Dezember 2017 20:34
>>>> *An: *mkgmap-dev at lists.mkgmap.org.uk 
>>>> <mailto:mkgmap-dev at lists.mkgmap.org.uk>
>>>> *Betreff: *Re: [mkgmap-dev] DEM File Format and mkgmap
>>>>
>>>> Hi Andreas
>>>>
>>>> I have been able to make it work (tapping on the arrows) on my 
>>>> Oregon 600 but its very sluggish and at one stage it just freezes.
>>>>
>>>> I think you are right ; there is an issue.
>>>>
>>>>
>>>> On 15/12/2017 19:30, Andreas Schmidt wrote:
>>>>> Hi Frank,
>>>>>
>>>>> with ypur great tool I am able to
>>>>>
>>>>> - have3d - View in basecamp
>>>>> - hillshading on Oregon600
>>>>>
>>>>> Thats really amazing !
>>>>>
>>>>> In Oregon there is also a menu item „3D“. Even if the map Shows Up 
>>>>> hillshading,, this function doesnt work. Oregon complains that the 
>>>>> map does Not have enough hight information.
>>>>>
>>>>> Could you make it work on your device?
>>>>>
>>>>> Andreas
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> Gesendet mit der Telekom Mail App 
>>>>> <http://www.t-online.de/service/redir/emailmobilapp_ios_smartphone_footerlink.htm>
>>>>>
>>>>>
>>>>>
>>>>> -----Original-Nachricht-----
>>>>> Von: Frank Stinner <frank.stinner at leipzig.de>
>>>>> Betreff: Re: [mkgmap-dev] DEM File Format and mkgmap
>>>>> Datum: 08.12.2017, 09:27 Uhr
>>>>> An: mkgmap-dev at lists.mkgmap.org.uk
>>>>> Hi,
>>>>>
>>>>> i must confess, i have never tried to decompilea garmin dem map. I 
>>>>> have only playing with bit-patterns and then lookingfor the result 
>>>>> in mapsource. But i'm sure, that we have different algorithmsor 
>>>>> one algorithm with different special cases.
>>>>>
>>>>> My description in the pdf is (only) validfor the „TOPO Deutschland 
>>>>> v3“. Please see the pages 3 and 4. There area few "unknown values".
>>>>>
>>>>> For example see "Codierungstyp"(coding type) for a 64x64 tile. I 
>>>>> found in different garmin maps valuesfrom 0 to 6. 0 is the 
>>>>> standard. It seems to be, that the coding type haveno influence of 
>>>>> the algorithm, but i'm not sure. Presumable is this typeonly 
>>>>> important for different interpretations of the height values. 
>>>>> BuildDEMFileuse type 1 for areas with "unknown height". This is in 
>>>>> this casethe interpretation for height=maxvalue.
>>>>>
>>>>> Unknown is also the byte on position 0x25in the dem header. In the 
>>>>> „TOPO Deutschland v3“ there we have 0x1 buti have also seen in 
>>>>> other maps 0x0.
>>>>>
>>>>> Interesting is also the word in 0x12 in evereyzoomlevel definition 
>>>>> (see page 26 in the pdf). In the „TOPO Deutschlandv3“ thats all 0. 
>>>>> But i have also found 0x100, 0x200, 0x400. Perhaps akind of 
>>>>> multiplier for heights?
>>>>>
>>>>> Very important is the bytes 0x0 (and 0x1)in everey zoomlevel 
>>>>> definition. In the „TOPO Deutschland v3“ 0x0 is ever0. 0x1 seems 
>>>>> to be a number as "link" to a maplevel. But i don'treally 
>>>>> understand the sense ot that. We can have 6 maplevels and we 
>>>>> cansay the maplevel 2 and 4 are without dem's?
>>>>>
>>>>> In a little demo map from garmin i have see"twins" of 
>>>>> zoomlevelnumbers, one with value 0 on 0x0 and onewith 1 on 0x0. 
>>>>> Perhaps 0x0 is for different and optimized output on pcand gps?
>>>>>
>>>>> I think, a decompiler with the algo frommy pdf is working only for 
>>>>> this special case:
>>>>> 0x15 in dem header should be 0 (meter)
>>>>> 0x25 in dem header should be 1
>>>>> 0x0 and 0x12 in every zoomlevel should 0
>>>>>
>>>>> By the way, have anybody see a dem with valuesin foot? The values 
>>>>> in such a dem should be greater then for a dem in meter.Have 
>>>>> anybody height values with a precision of foot? The conversion 
>>>>> fromfoot to meter would be a first compression step. If garmin 
>>>>> really use "foot",then a different/better compression algo make 
>>>>> sense.
>>>>>
>>>>>
>>>>> Frank
>
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