# Regridding fine to coarse and missing lon/lat coords in fine GOES-16 FOV grid

**URL:** <https://discourse.pangeo.io/t/regridding-fine-to-coarse-and-missing-lon-lat-coords-in-fine-goes-16-fov-grid/2391>\
**Category:** Science\
**Created:** [April 6, 2022, 4:20pm UTC](https://discourse.pangeo.io/t/regridding-fine-to-coarse-and-missing-lon-lat-coords-in-fine-goes-16-fov-grid/2391 "2022-04-06T16:20:59Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![jwsmit12](https://avatars.discourse-cdn.com/v4/letter/j/d9b06d/32.png) [@jwsmit12](https://discourse.pangeo.io/u/jwsmit12)\
**Post date:** [April 6, 2022, 4:20pm UTC](https://discourse.pangeo.io/t/regridding-fine-to-coarse-and-missing-lon-lat-coords-in-fine-goes-16-fov-grid/2391/1 "2022-04-06T16:20:59Z")

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I have been trying multiple regridding software available in Python (i.e xESMF, xarray coarsen, pyresample, ESMFPy, etc…) and otherwise (cdo, nco ncremap, ncl ESMF\_Regrid, etc…).

I have the file of the GLM field of view longitudes/latitudes. I used Brian Blaylocks’s script here: [goes2go/create\_standard\_GOES\_latlon\_grids.ipynb at master · blaylockbk/goes2go · GitHub](https://github.com/blaylockbk/goes2go/blob/master/latlon_grids/create_standard_GOES_latlon_grids.ipynb) to generate the the GOES 16 FOV. As you know it is 5424 x 5424 file and it also has missing values

I presume that the missing values in these files come from the projection of the FOV onto a sphere.

With most of the regridding software (cdo, ncl ESMF Regrid, nco ncremap, etc), a netcdf file needs to include variables that contain the a variable of 4 corners of each of a 2-D lon lat or 2 bounds of a 1-D lon/lat. So I have added those variables. In these cases within the GOES FOV file, a subset of grids will either have all or 1-3 of the 4 are missing values… In other words, the grid is not well defined.  
The missing values are usually printed out to an automatic fill\_value number of 1e+20 or 9.96e+36, hence the calculation this throws the regridding calculation off. And I usually try to do a conservative regridding with any of the software where that option is available since I am going from a very fine 5424 x 5424 to 128 (1.25 degree Lon) to 162 (1 degree lat).

Would it be wise to do some type of interpolation to estimate those missing coordinates with the GOES-16 FOV? Or should I use a fixed coordinate system where the coordinates are (0,0) to (5424,5424)? Do I need to mask out the missing coordinates?

I am taking a stab in the dark at this point. I don’t know if the missing values are my problem but trying to get to a solution.

Thanks  
Jonathan