[GRASS-dev] Grass SVN in Android, display issue

[Sören Gebbert]

Hi Glynn,
I have created a ticket for this issue:
http://trac.osgeo.org/grass/ticket/1752

So we can discuss this using the trac ticket system.

Best regards
Soeren

2012/10/1 Glynn Clements <glynn at gclements.plus.com>:
>
> Sören Gebbert wrote:
>
>> > The ideal solution would be to store runs of >= 254^2 as multiple
>> > runs. That would maintain backward compatibility while avoiding the
>> > bug. But that would require re-writing Rast3d_rle_encode() and
>> > Rast3d_rle_count_only(); there's no way that G_rle_codeLength and
>> > rle_length2code can be fixed, as they assume that any length can be
>> > encoded.
>>
>> So this bug is not fixable at all?
>
> The bug is fixable, but the fix isn't trivial.
>
>> >> However, i do not understand the advantage of having RLE first and a
>> >> LZ77 or LZ78 compression afterwards.
>> >> Shouldn't be the LZ77/78 compression sufficient for compression of
>> >> float/double values?
>> >
>> > For sparse data, using RLE first can often provide a noticeable
>> > improvement.
>>
>> I would prefer to disable RLE and keep the code only for backward compatibility.
>
> That's certainly simpler, but you should first check how much
> difference it makes to a sparse (e.g. all-zeros) map.
>
> --
> Glynn Clements <glynn at gclements.plus.com>