Re: [gdal-dev] Histograms without null pixels

2013-03-05 Thread Chaitanya kumar CH
Caleb, On Tue, Mar 5, 2013 at 11:53 AM, Caleb Hanger cdhan...@gmail.com wrote: On Tue, Mar 05, 2013 at 11:19:27AM +0530, Chaitanya kumar CH wrote: Caleb, gdalinfo uses the GetDefaultHistogram() method which can do this faster by fetching a precomputed histogram. What do you mean?

Re: [gdal-dev] Histograms without null pixels

2013-03-05 Thread Caleb Hanger
On Tue, Mar 05, 2013 at 01:31:01PM +0530, Chaitanya kumar CH wrote: On Tue, Mar 5, 2013 at 11:53 AM, Caleb Hanger cdhan...@gmail.com wrote: What do you mean? The histogram is only precomputed if gdalinfo has been run previously and stored a cache of data (the XML file) for later reference;

Re: [gdal-dev] Histograms without null pixels

2013-03-05 Thread Chaitanya kumar CH
The main usage of gdalinfo is manual inspection of the image. It was not intended for use within other scripts. The output is formatted for human reading. On Tue, Mar 5, 2013 at 9:00 PM, Caleb Hanger cdhan...@gmail.com wrote: On Tue, Mar 05, 2013 at 01:31:01PM +0530, Chaitanya kumar CH wrote:

[gdal-dev] Histograms without null pixels

2013-03-04 Thread Caleb Hanger
All, I am writing a script which is calling gdalinfo to get a histogram of pixel values in an image file. Apparently the mechanism for obtaining a default histogram enables the bIncludeOutOfRange flag to dump not-in-range pixels (including null pixels, in formats that support it) into

Re: [gdal-dev] Histograms without null pixels

2013-03-04 Thread Chaitanya kumar CH
Caleb, gdalinfo uses the GetDefaultHistogram() method which can do this faster by fetching a precomputed histogram. gdalinfo is a command line program. Even a default histogram of 256 buckets is hard to visualize in text mode. A much better way is to use a desktop GIS like qgis to view the

Re: [gdal-dev] Histograms without null pixels

2013-03-04 Thread Caleb Hanger
On Tue, Mar 05, 2013 at 11:19:27AM +0530, Chaitanya kumar CH wrote: Caleb, gdalinfo uses the GetDefaultHistogram() method which can do this faster by fetching a precomputed histogram. What do you mean? The histogram is only precomputed if gdalinfo has been run previously and stored a