[OSGeo-Discuss] format for raster data distribution, JP2?

[Michael P. Gerlek]

Well, you've covered most of the tradeoffs - proprietary/open, general
availability, etc.  At the end of the day, it's hard to beat compressed
TIFFs.  (lzw-compressed TIFFs are nice too - maybe a bit less supported than
jpeg-compressed, but no quality loss)

 

-mpg

 

 

From: discuss-bounces at lists.osgeo.org
[mailto:discuss-bounces at lists.osgeo.org] On Behalf Of John Callahan
Sent: Friday, July 15, 2011 11:59 AM
To: OSGeo Discussions; qgis-user at lists.osgeo.org
Subject: [OSGeo-Discuss] format for raster data distribution, JP2?

 

I'm looking for advice on sharing raster data for download.  We distribute
several raster datasets such as DEMs and orthophotography.  Sometimes these
are divided into rectangular tiles, sometimes by geography/boundaries.  Most
of our audience has some level of GIS or CAD experience. We also have WMS
services but there are many times where people need the actual data files.

I had been creating JP2 files using JP2ECW compression.  Great file size
reduction with very good quality. However, I'm thinking it may be difficult
for people to view these (and more difficult for me to create) due to the
restrictions on the codec distribution.  The other JP2 options, OpenJPEG and
libjasper, seems like they also require users to obtain this codec/driver
and install into the software first.   Same for the commercial Kakadu and
MrSID.  netCDF is great but not widely supported; IMG are good but not any
advantage over TIFs (except for > 4 GB file sizes)

Since I want to serve the widest possible audience (and not cater only to
our Windows/ArcGIS audience), I'm down to serving TIFs with JPEG compression
at around quality=75, which is what I started with years ago!  Good quality,
decent compression, wide support.   Is this the best bet?   Is there
something else out there I'm overlooking?

- John

***********************************
John Callahan, Research Scientist
Delaware Geological Survey
University of Delaware
URL: http://www.dgs.udel.edu
*******************************

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