[mkgmap-dev] Error when not using dem-poly

Mon Jan 8 13:23:37 GMT 2018

Basically my idea was, if I always double the zoom-level (dist = 4000,
8000, ...) then I just need to calculate the highest resolution and all
others can be produced by just throwing out every 2nd value. It's not
related to zipped input. It would be faster I think, but definitely less
flexible. So I'm not sure, if it's worth thinking about it.

Henning

On 08.01.2018 20:59, Gerd Petermann wrote:
> Hi Henning,
>
> Do you think that a certain value would allow faster processing of zipped files?
> Well, we probably always have to unzip most of the file, but with a clever algorithm we may be able to store only
> needed values. For dem-dists below 10000 this is probably nearly every value, for much higher values it might be possible
> to omit some. This gets more complicated when you take into account that img tiles don't fully overlap hgt bounds
> and even more complex with --dem-poly.
> I think the code would be quite complex and I don't expect much improvement reg. heap memory.
>
> Before coding that I'd prefer to extract zip files into a temp file directory and use the MappedByteBuffer class as with normal hgt files.
> This seems to manage memory very well for our purpose, at least with Oracles JRE.
>
> Gerd
>
> ________________________________________
> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Henning Scholland <osm at hscholland.de>
> Gesendet: Montag, 8. Januar 2018 13:36:46
> An: mkgmap-dev at lists.mkgmap.org.uk
> Betreff: Re: [mkgmap-dev] Error when not using dem-poly
>
> Hi Gerd,
> I was thinking about the distance-values for DEM.
>
> Henning
>
> On 08.01.2018 20:35, Gerd Petermann wrote:
>> Hi Henning,
>>
>> no idea what that means. Where would you use these values?
>> The data in hgt files is stored as 16 bit signed integer value in metres.
>>
>> Gerd
>>
>> ________________________________________
>> Von: mkgmap-dev <mkgmap-dev-bounces at lists.mkgmap.org.uk> im Auftrag von Henning Scholland <osm at hscholland.de>
>> Gesendet: Montag, 8. Januar 2018 12:56:18
>> An: mkgmap-dev at lists.mkgmap.org.uk
>> Betreff: Re: [mkgmap-dev] Error when not using dem-poly
>>
>> Hi Gerd,
>> one general question: Do you see any advantage in using 'rounded' binary
>> values or doesn't it matter at all?
>> Henning
>>
>> On 08.01.2018 18:21, Gerd Petermann wrote:
>>> Hi Nick,
>>>
>>> thanks for reporting. I'll try to reproduce the problem. Please note that
>>> overview-dem-dist=888888
>>> is probably too large, 88888 would be a "normal" value.
>>>
>>> Gerd
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