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Re: java applet and data in metric coordinates



Paul,

The java map applet actually has functionality inside of it to deal with images where the axes are not to be interpreted as longitude and latitude.  But access to that capability has never been included in the LAS code built around the applet.  It would be a development task of unknown scope to provide robust support for LAS region selection where the selection was based on a map image whose X and Y coordinates did not map linearly onto longitude and latitude.  Given our broader goals of data intercomparison, I hope you can sympathize with our insistence that every dataset be geo-located.

One thing to remember is that the <livemap>, <grid> and <axis> information specified in the XML configuration files is only for the use of the LAS User Interface (UI) server.  It's OK to lie to the UI about these items, knowing that you'll take care of inconsistencies on the product server side.

Using your case as an example, you can create an <livemap> image that extends somewhat beyond your region of interest and then define a <grid> and <axes> (using lon and lat) that bound your data.  Now any incoming request will specify a region of longitude and latitude which you will have to convert into the coordinate space of your 'curvilinear' data.  That's all. ;-)

Luckily, we have a couple of ongoing collaborations with modeling groups that use curvilinear coordinates and the Ferret developers have recently added functions that allow you to perform just such a mapping.  This has not appeared in an official release yet, but you may contact Ansley Manke to request a beta version of this capability for testing.

I believe this will solve your dilemma but let me know if I have misunderstood the problem or your desired solution.


-- Jon


Paul Hasenohr wrote:
Dear LAS users,

I am currently assessing how a combination of OpenDAP freeform server + LAS could suit our needs for serving NOAA AVHRR data specifically processed for us (mainly the map projection is very unusual).
OpenDAP is working fine, so I try to access it via the LAS.
I described the dataset in a noaa.xml file included in las.xml.
I also created a custom ui xml file.
I copied these files at the end of my email.
My problem are
	1) when I reach the Constraints page, the java applet does not allow me to select an area. The values displayed for latitude are correct (from -2275900 to 2044900 m) but for longitude, it always remains blocked at 20E. I can not change this value in the text boxes and I can not draw anything in the java applet
	2) if I select the "no applet" version, I get an exception from tomcat.

Could you please give me some suggestions ?

Below are the characteristics (size) of the file I want to serve and my custom ui and las include xml files.

Best regards,
Paul

A]Coordinates of the data to be accessed via the LAS:

Pixel Size = (1100.00000000,-1100.00000000)
Corner Coordinates:
Upper Left  (-3246100.000, 2044900.000) ( 37d20'37.25"W, 59d 1'58.81"N)
Lower Left  (-3246100.000,-2275900.000) (  9d36'30.08"W, 25d26'30.95"N)
Upper Right ( 3367100.000, 2044900.000) ( 84d10'49.20"E, 58d18'10.33"N)
Lower Right ( 3367100.000,-2275900.000) ( 55d59'32.72"E, 25d 1'8.85"N)

B]noaa.xml (included in las.xml)
<datasets>
<noaa_20030623
  name="noaa AVHRR"
  url="" class="moz-txt-link-rfc2396E" href="">"http://marspclx1/cgi-bin/dods/nph-dods/dods/noaa/20030623/IMAGE.bin"
  doc="doc/toto.htm">
  <institution name="EC-JRC-IPSC-AGRIFISH-MARSSTAT" url="" class="moz-txt-link-rfc2396E" href="">"http://agrifish.jrc.it"/>
  <variables>
  <band1 name="Band 1">
    <link match="/lasdata/grids/noaa_20030623_grid"/>
  </band1>
  <band2 name="Band 2">
    <link match="/lasdata/grids/noaa_20030623_grid"/>
  </band2>
  <band3 name="Band 3">
    <link match="/lasdata/grids/noaa_20030623_grid"/>
  </band3>
  <band4 name="Band 4">
    <link match="/lasdata/grids/noaa_20030623_grid"/>
  </band4>
  <band5 name="Band 5">
    <link match="/lasdata/grids/noaa_20030623_grid"/>
  </band5>
  </variables>
  <properties>
    <ui>
      <default>file:ui.xml#noaa_ui</default>
    </ui>
  </properties>
</noaa_20030623>
</datasets>
<grids>
  <noaa_20030623_grid>
    <link match="/lasdata/axes/noaa_20030623_x"/>
    <link match="/lasdata/axes/noaa_20030623_y"/>
  </noaa_20030623_grid>
</grids>
<axes>
  <noaa_20030623_x type="x" units="metre">
    <arange start="-3246100.000" step="1100" size="6013"/>
  </noaa_20030623_x>
  <noaa_20030623_y type="y" units="metre">
    <arange start="-2275900.000" step="1100" size="3929"/>
  </noaa_20030623_y>
</axes>

C]noaa_ui.xml (included in ui.xml)
<images>
  <!--<image name="Image_NOAA" url=""
  	 bounds="-180,180,-90,90"/>-->
  <image name="Image_NOAA" url=""
  	 bounds="-3246100,3367100,-2275900,2044900"/>
</images>
<menus>
  <menu type="regions" name="NOAA_region">
    <!--<item values="-37.3305,84.167378,25.02578,59.03244">No regions available</item>-->
    <item values="-3246100,3367100,-2275900,2044900">No regions available</item>    
  </menu>
</menus>
<maps>
  <map type="livemap" name="NOAA_livemap">
    <image href=""/>
    <menu href=""/>
  </map>
</maps>
<defaults>
  <default name="noaa_ui">
    <map href=""/>
    <map href=""/>
    <map href=""/>
    <map href=""/>
  </default>
</defaults>


Paul HASENOHR
European Commission - Joint Research Centre
IPSC - Agriculture and Fisheries Unit
TP 266, 21020 ISPRA (VA), ITALY
Direct : +39 0332 78 62 22 - Fax : + 39 0 332 78 51 62
Web site: http://agrifish.jrc.it 


  

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