[GRASS-dev] GRASS GIS Map Display

Michael wrote:

Unless there is some kind of geocoded version of PNG's (I don't
know of any), the PNG would not be georeferenced and hence not
useable in any way for the GIS without some kind of
transformation.

for the record, you can create a "worldfile" for a PNG the same
as for a plain TIFF image, and GDAL will pick it up. It needs to
be named the same as the image but with a .pgw extension.
  http://gdal.org/frmt_various.html#PNG

I'm not sure if anything other than GDAL-based things would
respect that though, or if this trick helps for Sudeep's
question or not.

(GDAL's virtual-raster format is another wonderful cpu-saving
device worth mentioning btw)
  http://www.gdal.org/gdal_vrttut.html

Hamish

Good to know. Thanks. I've never seen it for other geospatial data entry, but good to know that GDAL can read such a file.

Michael
____________________
C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)
www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Aug 13, 2011, at 8:52 PM, Hamish wrote:

Michael wrote:

Unless there is some kind of geocoded version of PNG's (I don't
know of any), the PNG would not be georeferenced and hence not
useable in any way for the GIS without some kind of
transformation.

for the record, you can create a "worldfile" for a PNG the same
as for a plain TIFF image, and GDAL will pick it up. It needs to
be named the same as the image but with a .pgw extension.
Raster drivers — GDAL documentation

I'm not sure if anything other than GDAL-based things would
respect that though, or if this trick helps for Sudeep's
question or not.

(GDAL's virtual-raster format is another wonderful cpu-saving
device worth mentioning btw)
VRT -- GDAL Virtual Format — GDAL documentation

Hamish

Thanks Hamish, Michael and Rashad . I will let know if I have some luck with this.

On Sun, Aug 14, 2011 at 10:14 AM, Michael Barton <Michael.Barton@asu.edu> wrote:

Good to know. Thanks. I’ve never seen it for other geospatial data entry, but good to know that GDAL can read such a file.

Michael


C. Michael Barton
Director, Center for Social Dynamics & Complexity
Professor of Anthropology, School of Human Evolution & Social Change
Arizona State University

voice: 480-965-6262 (SHESC), 480-727-9746 (CSDC)
fax: 480-965-7671 (SHESC), 480-727-0709 (CSDC)

www: http://www.public.asu.edu/~cmbarton, http://csdc.asu.edu

On Aug 13, 2011, at 8:52 PM, Hamish wrote:

Michael wrote:

Unless there is some kind of geocoded version of PNG’s (I don’t
know of any), the PNG would not be georeferenced and hence not
useable in any way for the GIS without some kind of
transformation.

for the record, you can create a “worldfile” for a PNG the same
as for a plain TIFF image, and GDAL will pick it up. It needs to
be named the same as the image but with a .pgw extension.
http://gdal.org/frmt_various.html#PNG

I’m not sure if anything other than GDAL-based things would
respect that though, or if this trick helps for Sudeep’s
question or not.

(GDAL’s virtual-raster format is another wonderful cpu-saving
device worth mentioning btw)
http://www.gdal.org/gdal_vrttut.html

Hamish