Georeferencing JPEG 2000 Images
The JPEG 2000 image format is an ISO standard. There are now several desktop GIS applications that can read JPEG 2000 image files. However, there is no open standard that describes the metadata required to allow those images to be georeferenced. So right now, even though JPEG 2000 is a standard image format, it is not an interoperable format within the geospatial community.
Around the middle of 2004 (I think) the OpenGeospatial Consortium (OGC) received several submissions on how the georeferencing metadata could be encoded using GML. The submissions seemed simple enough. At time the general feeling was that a standard would be forthcoming by the end of 2004.
Well, 2005 is mostly history and no standard had been sighted. Meanwhile, anyone who wants to use JPEG 2000 in the geospatial realm is unable to do so unless they working in a single vendor environment (with some exceptions).
A colleague pointed me to a discussion paper available on the OGC website entitled “GML in JPEG 2000 for Geographic Imagery (GMLJP2)”. The scope of the standardisation effort seems to have grown to include:
- Coverage encoding – descriptions of the coverage geometry and content values.
- Coverage metadata – arbitrary metadata content.
- Image annotation – drawing attention to some region of an image.
- Geographic features – any GML feature collection.
- Feature and annotation styling – visual presentation of geographic features.
- Coordinate reference systems.
- Units of measure.
I can see the value in these capabilities. They also make sense if you look at the list of contributors to the discussion paper. They are mostly from companies interested in image data creation, management and high end processing.
My question: What happened to enabling simple interoperability between applications for the vast majority of people who simply want to read JPEG 2000 images into their GIS and have them display in the correct location? I thought that would have been the logical first step. It involves minimal effort and solves a simple problem for a lot of people. 80/20.
Note: I’m not an OGC member so I have no visibility of the standardisation process.
I stumbled across your blog mentioning GMLJP2 and I wanted to let you know that "enabling simple interoperability" can be attained by using the "minimal instance" as specified in the forthcoming GMLJP2 specification. We worked at lengths to ensure that a simple parser could find the appropriate information to satisfy the vanilla geocoding use case. I look forward to seeing your success with encoding in the future.
Martin Kyle — 4 December 2005, 02:32