[Geotiff] Re: [OSGeodata] File format for geo-coded ground-based photos

[Jo Walsh]

dear Ned, all,
On Wed, May 10, 2006 at 12:06:46PM -0400, Ned Horning wrote:
> The information stored with the photo data should include camera state 
> (focal length, date, time, frame size, resolution),
> location (geographic coordinates), and orientation (camera bearing,
> and possibly camera inclination) information. 
> 
> Would it make sense to extend the GeoTIFF format? 

On Wed, May 10, 2006 at 09:44:07AM -0700, Tyler Mitchell wrote:
> Ned,
> EXIF already has some stuff, of course.  I assume you've seen this..
> http://search.cpan.org/src/EXIFTOOL/Image-ExifTool-6.00/html/TagNames/GPS.html

It looks as if EXIF expresses almost everything that you need already, 
apart from camera inclination. 

http://www.exif.org/forum/topic.asp?TOPIC_ID=12 offers suggestions for
extra inclination properties in the 'EXIF GPS IFD'

http://akuaku.org/archives/2003/05/gps_tagged_jpeg.shtml talks about
extracting GPS information from EXIF headers where it's supplied, and
there are some useful links in the comments.

I'm not sure whether you are looking for embedded, or external,
metadata for your imagery; are you looking to make the photo metadata
available separately? If so, there was some work at the w3c on a
schema for EXIF that could be used with GeoRSS, RDF or any flavour of XML:
http://www.w3.org/2003/12/exif/   

Isn't there also some of JPEG2000 / GML work going on through the OGC? 
Michael Gerlek is involved in this and might be able to let you know
whether this is fit for your purposes and what the tradeoffs with EXIF
might be. 

> If a new standard needs to be developed how does one begin that
> process. Would the geodata committee of OSGeo be a good start?

If there is a question of wanting to propose extensions to a standards
maintainer like JEITA, and it would add weight for a proposal to come
from formally from OSGeo, then I think this would be appropriate for
us to put forward. Hopefully this is at least a good place for members
to put out feelers towards people who are more expert in any given
domain... 

cheers,


jo