[eml-dev] How to define Space Oblique Mercator projection in EML?...

[Matt Jones]

Hi Mark,

So far I haven't seen a reply to your message about this spatial
metadata question in EML a while back.  It seems like a significant
issue, so it should probably be entered into the EML bug list.
Unfortunately, I don't have the expertise to address it (I've been
waiting and hoping Peter might address it).  So maybe sending it out
again will get a response.  Could you describe the problem in a bug if
you haven't already resolved it?  Thanks,

Matt

Mark Servilla wrote:
> EML wizards and gurus,
> 
> I am having trouble defining the Space Oblique Mercator map projection
> in the spatialRaster subtree of EML.  The problem is unique to the SOM
> (any oblique map projection, for that matter) projection - the SOM does
> not use a prime meridian in the usual sense (i.e., it is fixed to the
> flight path of the Landsat satellite, not a geographic coordinate system).
> Since EML requires the primeMeridian-longitude and unit-name attributes
> to be strictly defined, the document will not validate.  Is there a
> recommendation *thanks in advance* from the EML community for how to deal
> with this issue, perhaps making the aforementioned attributes optional?
> 
> I have included below an example of how I would define this projection.
> 
> Notes:
> 1. The SOM projection does not appear to be common in the remote
> sensing world other than EOSAT/Landsat/IRS formats.  Unfortunately, we have
> much data in this projection.
> 2. FGDC has a separate element for this projection in their schema.
> Actually, FGDC has a separate element for each major projection definition.
> 
> <spatialReference>
>     <horizCoordSysDef name="SOM">
>         <projCoordSys>
>             <geogCoordSys>
>                 <datum/>
>                 <spheroid name="International_1909"
> semiAxisMajor="6378388"  denomFlatRatio="0.996633"/>
>                 <primeMeridian longitude=""/>
>                 <unit name="">
>             </geogCoordSys>
>             <projection>
>                 <parameter name="Landsat_Number" value="5"/>
>                 <parameter name="Landsat_Path" value="36"/>
>                 <parameter name="False_Easting" value="0"/>
>                 <parameter name="False_Northing" value="0"/>
>                 <unit name="meter">
>             </projection>
>         </projCoordSys>
>     </horizCoordSysDef>
> </spatialReference>
> 
> Sincerely,
> Mark

-- 
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Matt Jones                                     jones at nceas.ucsb.edu
http://www.nceas.ucsb.edu/    Fax: 425-920-2439    Ph: 907-789-0496
National Center for Ecological Analysis and Synthesis (NCEAS)
University of California Santa Barbara
Interested in ecological informatics? http://www.ecoinformatics.org
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