[thredds] aggregating gridded (tiled) netcdf files along lat and long to form one WMS layer

Hi there,

after playing around with Tiled aggregation i have something working now..


<dataset name="tiled" ID="tiled" urlPath="tiled/Agg.nc">
<metadata inherited="true">
<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
<aggregation dimName="latitude longitude" type="tiled">
<netcdf location="file:P:/foo_26_04_2011.nc.000.000" section="0:23,0:22"/>
<netcdf location="file:P:/foo_26_04_2011.nc.001.000" section="0:23,22:44"/>
<netcdf location="file:P:/foo_26_04_2011.nc.001.001" section="23:46,22:44"/>
<netcdf location="file:P:/foo_26_04_2011.nc.001.002" section="48:72,22:44"/>

the tiling works as expected.. however it requires us to generate the 'section' part, when this should already be clear by inspecting the lat/long variables/values. it also requires us to name every individual tile specifically, no scans or regexps. Is there no way around this at the current stage, we definitely need to populate this section for this to work ? some of our 'images' are comprised of hundreds of tiles, and may grow / contract as new areas are included.

Thanks for any comments,



Hi there,

apologies for this, i am sure its a stupid question but i have spent too much time already. I have a large number of netcdf files that are actually arranged as a grid/tiled fashion, (file-001-001, file-001-002..) .. representing the same variables and dimensions and points in time, just different spatially.

i want to make a virtual dataset that is the combination of all the tiles..which i will then map via WMS.

i have tried aggregating on the lat/long dimensions like this:

<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
<aggregation dimName="latitude" type="joinExisting" recheckEvery="4 sec">
<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
<aggregation dimName="longitude" type="joinExisting" recheckEvery="4 sec">
<scan location="E:/save/agg/" regExp="files_26_04_2011.nc.*" />

but it is not working, i get a 'smeared' version of a single tile.. and tried doing a simple union like this:

<netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";>
<aggregation type="union">
<scan location="E:/save/agg/" regExp="files_26_04_2011.nc.*" />

but i get only one tile rendered via WMS.

I cannot find any references to aggregations based on any dimension other than time, and am wondering if this is even possible.. but it seems like such a common thing to do i must be doing something dumb. i found one reference to a type of aggregation called 'tiled' but no doco anywhere for it.. maybe this is what i need ?

any suggestions would be appreciated



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