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[THREDDS #EAF-567984]: ncWMS GetMetadata: doesn't handle longitudes on 0-360 scale for irregular grids

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  • Subject: [THREDDS #EAF-567984]: ncWMS GetMetadata: doesn't handle longitudes on 0-360 scale for irregular grids
  • Date: Fri, 29 Jul 2011 11:48:07 -0600
Hi John,

I'm CCing Jon Blower on this to see what he thinks.

Ethan

John Maurer wrote:
> Hi TDS/ncWMS support,
> I use ncWMS GetMetadata calls to retrieve min and max data values for a
> given lat/lon bounding box in our Google Maps API. In order to skirt issues
> when spanning the dateline, I put longitudes on a scale of 0 to 360 rather
> than -180 to +180 to avoid an "invalid bounding box" error that occurs when
> the minimum longitude is positive and the maximum longitude is negative.
> While this works for many of our datasets, it returns null min/max values if
> the dataset is on an irregular grid (specifically curvilinear in our cases).
> Perhaps this scenario was overlooked and is a small bug in ncWMS? Here are
> some examples:
> 
> BBOX on 0-360 scale:
> 200.9783935546875,20.662341103925662,203.31985473632812,21.637005211106306
> 
> http://oos.soest.hawaii.edu/thredds/wms/hioos/roms_forec/hiog/ROMS_Oahu_Regional_Ocean_Model_best.ncd?service=WMS&version=1.3.0&REQUEST=GetMetadata&item=minmax&LAYERS=temp&BBOX=200.9783935546875,20.662341103925662,203.31985473632812,21.637005211106306&CRS=EPSG:4326&WIDTH=1705&HEIGHT=761&TIME=2011-07-20T21:00:00Z&ELEVATION=-0.016666666666666666
> 
> {"min":"","max":""}
> 
> Similar BBOX on -180 to +180 scale:
> 160.191650390625,20.174567450431844,-155.50872802734375,22.12381042563998
> 
> http://oos.soest.hawaii.edu/thredds/wms/hioos/roms_forec/hiog/ROMS_Oahu_Regional_Ocean_Model_best.ncd?service=WMS&version=1.3.0&REQUEST=GetMetadata&item=minmax&LAYERS=temp&BBOX=-160.191650390625,20.174567450431844,-155.50872802734375,22.12381042563998&CRS=EPSG:4326&WIDTH=1705&HEIGHT=761&TIME=2011-07-20T21:00:00Z&ELEVATION=-0.016666666666666666
> 
> {"min":25.126493,"max":26.430931}
> 
> Here are examples that span the dateline, to illustrate why I need to use
> the 0-360 scale:
> 
> BBOX on -180 to +180 scale gives invalid bounding box error:
> 
> http://oos.soest.hawaii.edu/thredds/wms/hioos/roms_forec/hiog/ROMS_Oahu_Regional_Ocean_Model_best.ncd?service=WMS&version=1.3.0&REQUEST=GetMetadata&item=minmax&LAYERS=temp&BBOX=164.6630859375,4.959615024698026,-120.41015624999999,35.817813158696616&CRS=EPSG:4326&WIDTH=1705&HEIGHT=761&TIME=2011-07-20T21:00:00Z&ELEVATION=-0.016666666666666666
> 
> {"exception":{"className":"uk.ac.rdg.resc.ncwms.exceptions.WmsException","message":"Invalid
> bounding box format"}}
> 
> But again, a similar BBOX on 0-360 scale returns null for a curvilinear
> dataset:
> 
> http://oos.soest.hawaii.edu/thredds/wms/hioos/roms_forec/hiog/ROMS_Oahu_Regional_Ocean_Model_best.ncd?service=WMS&version=1.3.0&REQUEST=GetMetadata&item=minmax&LAYERS=temp&BBOX=164.6630859375,4.12728532324537,239.58984375,35.137879119634185&CRS=EPSG:4326&WIDTH=1705&HEIGHT=761&TIME=2011-07-20T21:00:00Z&ELEVATION=-0.016666666666666666
> 
> {"min":"","max":""}
> 
> Just to prove that it works for regular gridded datasets, here are a couple
> URLs on 0-360 scale that work:
> 
> http://oos.soest.hawaii.edu/thredds/wms/hioos/model/wav/swan/oahu/SWAN_Oahu_Regional_Wave_Model_best.ncd?service=WMS&version=1.3.0&REQUEST=GetMetadata&item=minmax&LAYERS=shgt&BBOX=201.4391326904297,21.231782183740147,202.60986328125,21.718041902388794&CRS=EPSG:4326&WIDTH=1705&HEIGHT=761&TIME=2011-07-20T21:00:00Z
> 
> {"min":0,"max":1.9349945}
> 
> http://oos.soest.hawaii.edu/thredds/wms/hioos/model/atm/ncep_global/NCEP_Global_Atmospheric_Model_best.ncd?service=WMS&version=1.3.0&REQUEST=GetMetadata&item=minmax&LAYERS=tmp2m&BBOX=0,-78.9039293885709,360,78.97138592818217&CRS=EPSG:4326&WIDTH=1705&HEIGHT=761&TIME=2011-07-20T21:00:00Z
> 
> {"min":215.5,"max":321}
> 
> Thanks for giving this a look!
> Cheers,
> John Maurer
> Pacific Islands Ocean Observing System (PacIOOS)
> University of Hawaii at Manoa



Ticket Details
===================
Ticket ID: EAF-567984
Department: Support THREDDS
Priority: High
Status: Open