[gdal-dev] Need help converting a geotiff file to jpg/tiff/bmp
Benjamin R Welton
benjamin.r.welton at wmich.edu
Mon Dec 1 10:38:06 EST 2008
Thanks for your quick response.
The geotiff files that i am trying to convert are single band. I am not looking to create a false three color tiff from these images i only need to have a gray scale representation of the images.
Iv had a little bit of time to look over the documentation on the VRT Driver. It looks like i could essentially use the same template for all of the images with only the filename and xsize/ysize altered for each file. Ill make an attempt to do the conversion using the VRT files and see if i can get the image i want by using that process. One quick question though, is there any file size or area limits on how large the VRT could do a conversion for? The files that i am doing this conversion on are not really large (2000x4500 pixels max) so i am assuming that it will be fine.
Thanks for your help,
----- Original Message -----
From: Frank Warmerdam <warmerdam at pobox.com>
Date: Wednesday, November 26, 2008 9:31 pm
Subject: Re: [gdal-dev] Need help converting a geotiff file to jpg/tiff/bmp
> Benjamin Welton wrote:
> > Hello everyone,
> > Im quite new to using GDAL and what i would like to do is convert
> > geotiff file to a standard jpeg/tiff/bmp image file so that it
> can be
> > viewed by any standard image reading software (ideally i would
> like to
> > be able to display said image using wxPython) . Every time i try
> > convert an image it creates ether an image that is not compatible
> > some basic image viewing/editing tools or it creates and image
> that is
> > monochrome and all detail of the image is lost. What would be the
> > way to go about creating a standard jpeg/tiff/bmp so that it can
> > viewed in basic image editing/viewing tools? The geotiff is a
> > datatype file and i do not really need to keep any of the actual
> > georeferencing information contained in the geotiff file.
> > Here is the python code that i am using to convert the image to a
> > standard tiff file:
> > dataset = gdal.Open( "C:\\Geotiff.tif", GA_ReadOnly )
> > format = "GTiff"
> > driver = gdal.GetDriverByName( format )
> > metadata = driver.GetMetadata()
> > dst_ds = driver.CreateCopy("C:\\Example.tiff",dataset,0,
> > ["PROFILE=BASELINE"] )
> > Any help anyone could provide to me would be great.
> How many bands does the int16 geotiff file have?
> Generally, the hard part here is converting the int16 image pixels to
> Byte to produce a fairly universal output file. The proper way to do
> this would likely be to create an intermediate virtual file that
> appliesscaling and a conversion of data type; however, this may be
> I'm also concerned that you have a one band file and that you are
> hopingfor colorization based on some undefined scheme, but I'll
> need to know
> more about the source file to know the answer to that.
> The following VRT file demonstrates using a ComplexSource to rescale
> an image from 16bit to 8bit. You could construct something similar
> to use in your Python (substituting in appropriate sizes, extra bands,
> <VRTDataset rasterXSize="512" rasterYSize="512">
> <VRTRasterBand dataType="Byte" band="1">
> <SourceFilename relativeToVRT="1">utm.tif</SourceFilename>
> <SrcRect xOff="0" yOff="0" xSize="512" ySize="512"/>
> <DstRect xOff="0" yOff="0" xSize="512" ySize="512"/>
> Best regards,
> I set the clouds in motion - turn up | Frank Warmerdam,
> warmerdam at pobox.comlight and sound - activate the windows |
> http://pobox.com/~warmerdamand watch the world go round - Rush |
> Geospatial Programmer for Rent
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