[mapserver-dev] Re: RFC for XMP metadata support

Daniel Morissette dmorissette at mapgears.com
Thu Jul 7 11:45:01 EDT 2011

Hi Paul,

Here are a few questions/comments:

- The proof of concept code attached to ticket #3932 is executed in all 
cases. The real implementation should be conditional to the presence of 
xmp_* metadata to avoid calling xmp_init() and reopening the output file 
unnecessarily when this feature is not used. (I presume you were going 
to do that already but that was not explicitly stated in the RFC)

- Instead of focusing on license metadata, could we not make it so that 
any xmp_* metadata triggers this feature and ends up writing the 
corresponding metadata to the output?

- As Thomas already pointed out, it would be ideal to have support for 
this via the default output formats as well and not just GDAL based formats


On 11-07-07 11:29 AM, Paul Ramsey wrote:
> No concerns, questions?
> On Mon, Jul 4, 2011 at 9:10 AM, Paul Ramsey<pramsey at cleverelephant.ca>  wrote:
>> Devs,
>> I've prepared a draft RFC for adding embedded metadata into output
>> images produced by MapServer.
>>   http://trac.osgeo.org/mapserver/attachment/ticket/3932/ms-rfc-7X.txt
>> I'm looking for feedback now before I number and commit it and ask for
>> a vote. Here's the preamble so you don't have to click:
>> XMP is the "extensible metadata platform" [1]_ which allows the
>> embedding of metadata information across a wide range of document and
>> image formats: PNG, GIF, JPEG, PDF, etc. XMP was originally developed
>> by Adobe [2]_ and is supported across their product line. It is now
>> being increasingly included in other standards for metadata embedding
>> and supported by tools for viewing image information (e.g. exiftools).
>> Creative Commons has standards for using XMP to embed commons
>> licensing [3]_ in images and other document, including a specific
>> creative commons schema. One of the challenges of advertising
>> licensing and terms of use in WMS and other web mapping services is
>> that the terms are usually advertised separately from the actual
>> content. So a WMS service might specify terms in the Capabilities
>> document, but the images themselves will be unmarked. Embedding
>> license URLs inside the images themselves using a standard marking
>> allows organizations to be unambiguous about the conditions attached
>> to their content.
>> The goal of this change is to allow users the option of embedding XMP
>> metadata in their MapServer output using an open source XMP utility
>> library.
>> .. [1] http://en.wikipedia.org/wiki/Extensible_Metadata_Platform
>> .. [2] http://www.adobe.com/products/xmp/overview.html
>> .. [3] http://wiki.creativecommons.org/XMP
>> .. [4] http://libopenraw.freedesktop.org/wiki/Exempi
>> Thanks,
>> Paul
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Daniel Morissette
Provider of Professional MapServer Support since 2000

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