[Qgis-user] (no subject) - Compressing Raster

[Alex Mandel]

On 07/29/2014 10:31 AM, Etienne Tourigny wrote:
> On Tue, Jul 29, 2014 at 1:10 PM, Alex Mandel <tech_dev at wildintellect.com>
> wrote:
> 
>> On 07/29/2014 01:45 AM, Peter Versteeg wrote:
>>> thank you very much for the email.
>>>
>>>
>>>
>>> I think I am almost there. I have set the compression to LZW and did a
>>> export and I did a export on high compression. Both are still really big.
>>>
>>>
>>>
>>> in your first mail you explained about:
>>>
>>>
>>>
>>>             The type of number stored dictates a large amount of
>> overhead,
>>> there is
>>>                 a huge difference between Integer and Float.
>>>
>>>                 -co COMPRESS=LZW  -ot Int16
>>>
>>>                 See http://www.gdal.org/gdal_translate.html for options.
>>> Pick the
>>>                 smallest type of number storage that holds your data
>>> correctly. Most
>>>                 GDAL tools will default to Float, that is likely the
>>> difference.
>>>
>>>
>>>
>>> In the save raster as window where i also set the compress to LZW i did
>> try
>>> to ad a line but i do not know what to type.
>>>
>>> name: Int value 16 or name ot value int16 all do not work.
>>>
>>>
>>>
>>> Can you tell me what line to write
>>>
>>>
>>>
>>> gr Peter
>>>
>>
>> As I said in my previous email:
>> If that still isn't enough use GDAL Translate found on the Raster menu
>> under Conversion. There you will be able to set all the possible options.
>>
>> Basically the options are not in the Save As dialog. I will talk to the
>> developers about adding more options.
>>
> 
> You can do pretty much the same things as in the GDAL Translate tool - see
> the "Creation Options" group box. What is missing exactly?

-ot is missing, which lets you set the number type int/float etc

I have not tested if the save as dialog allows this, I was guessing that
only -co options were allowed in the Create Options section. -ot is not
a -co option, its a separate flag for gdal.

Thanks,
Alex