Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

Embedded in a geoPDF is info on the CTM - Coordinate Transformation Matrix.

I am unfamiliar with this CTM.

I know how to use python-numpy.

How (or is it even possible) for me to use the CTM information to get the latitude and longitude bounding box of the image?

Is more information need such as the pixel bounding box of the image?

Is there a simple matrix calculation some one can explain to me that I can do in numpy?

share|improve this question
up vote 2 down vote accepted

The development version of GDAL, v1.8, adds support for reading geospatial pdf's and has python bindings. See GDAL and Geospatial PDF on Windows for how to get started on that platform. For command line (non python) retrieving the bounding coordinates is as simple as:

gdalinfo foobar.pdf

# output edited for clarity
Corner Coordinates:
Upper Left  (  537538.956, 6877354.484) (140d16'57.58"W, 62d 1'35.87"N)
Lower Left  (  538223.133, 6841800.995) (140d16'37.73"W, 61d42'26.76"N)
Upper Right (  588329.654, 6878331.879) (139d18'43.06"W, 62d 1'37.03"N)
Lower Right (  589013.831, 6842778.391) (139d18'59.38"W, 61d42'27.99"N)
Center      (  563276.394, 6860066.437) (139d47'49.42"W, 61d52' 4.97"N)

For python examples see GDAL API tutorial and scan down to "Getting Dataset Information".

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.