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https://issues.apache.org/jira/browse/SIS-448?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Martin Desruisseaux resolved SIS-448.
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Resolution: Fixed
> Extension to CF-conventions for localization grid smaller than data in netCDF
> -----------------------------------------------------------------------------
>
> Key: SIS-448
> URL: https://issues.apache.org/jira/browse/SIS-448
> Project: Spatial Information Systems
> Issue Type: Improvement
> Components: Storage
> Reporter: Martin Desruisseaux
> Assignee: Martin Desruisseaux
> Priority: Major
> Fix For: 1.0
>
>
> The _Global Change Observation Mission - Climate (GCOM-C)_ data have content
> like below (simplified):
> {noformat}
> group: Geometry_data {
> variables:
> float Latitude(161, 126)
> string Unit = "degree"
> string Dim0 = "Line grids"
> string Dim1 = "Pixel grids"
> int Resampling_interval = 10
> float Longitude(161, 126)
> string Unit = "degree"
> string Dim0 = "Line grids"
> string Dim1 = "Pixel grids"
> int Resampling_interval = 10
> }
> group: Image_data {
> variables:
> ushort SST(1599, 1250) // Note: different size than (latitude,
> longitude) variables.
> string dim0 = "Line grids"
> string dim1 = "Pixel grids"
> string Unit = "degree"
> }
> {noformat}
> The size of latitude and longitude variables is not the same than the size of
> image data. In this case, even if reader correctly identifies {{Latitude}}
> and {{Longitude}} as the variables to use for building a localization grid,
> we are still unable to associate the {{SST}} variable to those axes because
> they have no dimension in common. However if we interpret {{dim0}} and
> {{dim1}} attributes as _"Name of dimension 0"_ and _"Name of dimension 1"_
> respectively, then we can associate the same dimension *names* to all those
> variables: namely {{"Line grids"}} and {"Pixel grids"}} in above example.
> Using those names, we deduce that the ({{data_y}}, {{data_x}}) dimensions in
> the {{SST}} variable are mapped to the ({{grid_y}}, {{grid_x}}) dimensions in
> the localization grid.
> The feature is an extension to CF-conventions, as I'm not aware of equivalent
> mechanism in CF at this time. The {{coordinates}} attributes is not exactly
> the same since it tells us which variable to use, but not which dimensions
> (an ambiguity still exists if the variable has 2 or more dimensions).
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