[kepler-dev] GIS/GDAL question

[Kevin Ruland]

Dan,

Can you email me (not the list) one of these files?  I'd like to take a
look at it.

Thanks

Kevin

Dave Vieglais wrote:

>Hi Dan,
>
>from gdal-1.3.1/frmts/raw/ehdrdataset.cpp :
>
>        else if( EQUAL(papszTokens[0],"NBITS") )
>        {
>            if( atoi(papszTokens[1]) == 16 )
>                eDataType = GDT_Int16;
>            else if( atoi(papszTokens[1]) == 32 )
>                eDataType = GDT_Float32;
>            else if( atoi(papszTokens[1]) == 64 )
>                eDataType = GDT_Float64;
>        }
>
>http://www.esri.com/library/whitepapers/pdfs/eximgav.pdf implies INT, and also
>indicates a variety of sizes that are not covered by GDAL (notably 1 and 4
>bits not in gdal, 64 bit formats are not specified in the esri doc):
>
>"nbits—The number of bits per pixel per band. Acceptable values are 1, 4, 8,
>16, and 32. The default value is eight bits per pixel per band. For a true
>color image with three bands (R, G, B) stored using eight bits for each pixel
>in each band, nbits equals eight and nbands equals three, for a total of
>twenty-four bits per pixel. For an image with nbits equal to one, nbands must
>also equal one. "
>
>Other docs around the place indicate BIL in floating point format, or integer.
> Basically there is no mechanism in BIL to specify the type of data, just the
>size.  Apart from tweaking GDAL, there doesn't seem to be any simple fix for
>this - you could try something like reading the data into an im memory raster,
>casting to INT32 as you read the pixels, then do the transform on the in
>memory raster.  But that doesn't seem like something to do in Kepler.
>
>I would suggest converting the files with another product to GeoTiff, which is
>a much more robust format.
>
>Dave V.
>
>Dan Higgins wrote:
>  
>
>>Kevin,
>>    The docs I have found for gdal_translate have an output format but I
>>cannot find an input format. Do you have a reference or example for how
>>to specify the input?
>>
>>Dan
>>
>>Kevin Ruland wrote:
>>
>>    
>>
>>>Dan,
>>>
>>>I'll look into this in the morning.
>>>
>>>gdal_translate lets you specify input and output formats including
>>>representation.
>>>
>>>Kevin
>>>
>>>Dan Higgins wrote:
>>>
>>> 
>>>
>>>      
>>>
>>>>Hi All,
>>>>
>>>>  Any GIS/GDAL experts out there?
>>>>
>>>>  As part of the ENM/GARP workflows, we need to read and re-project 
>>>>some *.bil raster files. We are using some GDAL code in actors to do 
>>>>this. The problem is that one of the *.bil input files is specified with 
>>>>NBITS=32 in the *.hdr file. GDAL apparently assumes that NBITS=32 
>>>>corresponds to 32-bit floating point data, but some other applications 
>>>>assume it is 32 bit INT data!
>>>>
>>>>  The data is apparently 32 bit INTs. Is *.bil data always INT data? 
>>>>(It allows 8 and 16 bit data which are integers; I see no way of 
>>>>specifying what 32 bit data represents.) Is there any way in GDAL (eg 
>>>>GDALWARP) to set the assumed input datatype? (i.e. tell GDAL to assume 
>>>>INT rather than FLOAT?)
>>>>
>>>>Dan
>>>>
>>>>
>>>>
>>>>   
>>>>
>>>>        
>>>>
>>> 
>>>
>>>      
>>>
>>------------------------------------------------------------------------
>>
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>>    
>>
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