Raster internal tiling performance

[Gambin Dejan]

Thanks Frank, as always.

Like you said, the tiff file was compressed by CCITTFAX4 and today I
have read one of your posts where you noted that GDAL treated 1bit tiff
files as 8bit so maybe this was the reason the file was so big. Anyway,
I left all those files intacted, I suppose this won't be a problem..

Now I have another problem. I get a big tif file that gdalinfo reports
as:

Driver: GTiff/GeoTIFF
Size is 19999, 14969
Coordinate System is `'
Origin = (5410251.938003540000000,5035260.976484250300000)
Pixel Size = (1.000050002500120,-1.000050002500120)
Metadata:
  TIFFTAG_XRESOLUTION=9.9995003
  TIFFTAG_YRESOLUTION=9.9995003
  TIFFTAG_RESOLUTIONUNIT=3 (pixels/cm)
Corner Coordinates:
Upper Left  ( 5410251.938, 5035260.976)
Lower Left  ( 5410251.938, 5020291.228)
Upper Right ( 5430251.938, 5035260.976)
Lower Right ( 5430251.938, 5020291.228)
Center      ( 5420251.938, 5027776.102)
Band 1 Block=128x128 Type=Byte, ColorInterp=Red
  Overviews: 148x111
Band 2 Block=128x128 Type=Byte, ColorInterp=Green
  Overviews: 148x111
Band 3 Block=128x128 Type=Byte, ColorInterp=Blue
  Overviews: 148x111
........................................................................
.......
I wanted to create a tiled format using "gdal_translate -co TILED=YES
-co TFW=YES file.tif file_tiled.tif", but after a while I got error:

Input file size is 19999, 14969
0...10...20...30.ERROR 1: BUZET_10000.tif:DumpModeDecode: Not enough
data for sc
anline 0
ERROR 1: TIFFReadEncodedTile() failed.
ERROR 1: IReadBlock failed at X offset 0, Y offset 116
ERROR 1: GetBlockRef failed at X block offset 0, Y block offset 116
........................................................................
..............................................

What do you suggest?

> -----Original Message-----
> From: UMN MapServer Users List 
> [mailto:MAPSERVER-USERS at LISTS.UMN.EDU] On Behalf Of Frank Warmerdam
> Sent: Thursday, February 08, 2007 8:26 PM
> To: MAPSERVER-USERS at LISTS.UMN.EDU
> Subject: Re: [UMN_MAPSERVER-USERS] Raster internal tiling performance
> 
> Dejan Gambin wrote:
> > Hi,
> > 
> > I have a set of ~20 small tif files (100-500KB each). 
> Supposing I want 
> > to have a good "zoom-in" performance, will I gain much by 
> tiling them 
> > internally with gdal_translate before doing gdaltindex (and 
> gdaladdo 
> > after
> > that) on them?
> 
> Dejan,
> 
> Generally speaking internal tiling won't have much impact on 
> performance for tiny files in the 100-500KB size range 
> because it takes almost no time to pull the whole file into 
> RAM anyways.
> 
> > By the way, I have created one tiled tif file and it is very big 
> > relative to original (160MB tiled vs 350KB original)? I 
> haven't seen 
> > this such a difference in size before.
> 
> I would presume the original was compressed and the tiled 
> image was not.
> Converting to tiled format can very slightly increase the 
> size of an uncompressed file, but does not example anything 
> like what you are seeing.
> 
> Best regards,
> -- 
> ---------------------------------------+----------------------
> ----------
> ---------------------------------------+------
> I set the clouds in motion - turn up   | Frank Warmerdam, 
> warmerdam at pobox.com
> light and sound - activate the windows | http://pobox.com/~warmerdam
> and watch the world go round - Rush    | President OSGeo, 
> http://osgeo.org
>