Adding NetCDF4 Files to ArcMap

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04-28-2017 01:19 PM
AaronFriesz2
New Contributor II

I've experienced some complications in ArcMap 10.4.1 and ArcGIS Pro 1.3 while trying to review some NetCDF4 output files from a web application that my organization has been developing. I've added links to a couple of the NetCDF outputs below. I'm using the 'Make NetCDF Raster Layer' to import the NetCDF variable into ArcMap. The file named MOD13A1.005_aid0001.nc contains two variables... 1.) '_500m_16_days_NDVI' and 2.) '_500m_16_days_VI_Quality'. When I choose '_500m_16_days_NDVI' as my variable and execute the Make NetCDF Raster Layer tool, the data is imported into ArcMap as expected. However, when I choose '_500m_16_days_VI_Quality' as my variable, the Make NetCDF Raster Layer tool get hung up and never completes. I've had similar results in ArcGIS Pro except that instead of get hung up on the _500m_16_days_VI_Quality layer, the program just crashes. For the file named MCD12Q1.051_aid0001.nc, I've have no luck with either of the variables being imported into ArcGIS.

We've constructed the NetCDF4 files so they are CF-1.6 compliant, and the files have passed all the compliance checkers we've tried. I'm able to read in the NetCDF4 files into Python, perform operations, and visualize the each variable just fine.

Has anyone run into this problem before? Does anyone have any idea about what could be going wrong when trying to import these files?

Full transparency, I have been able to get these data into ArcGIS. I've changed the file extension from '.nc' to '.hdf' imported the variables as subdatasets. That works, but is not ideal. Any help would be much appreciated.

NetCDF File Links (files were too big to attach):

https://www.dropbox.com/s/wen1iuld4i111hk/MOD13A1.005_aid0001.nc?dl=0

https://www.dropbox.com/s/096kfdsqt4gp94q/MCD12Q1.051_aid0001.nc?dl=0

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AaronFriesz2
New Contributor II

Support for netCDF files in ArcMap and Pro seems to be complete dependent on whether the file is CF compliant. I've heard this before, but thought there might be some wiggle room. When my files are passed through a compliance checker they pass most of the checks except for a couple warnings pertaining the the data type of some the variables. That was the snag. CF conventions dictate that netCDF variable data types can only be char, byte, short, int, float or real, and double. Some of the variables in our files are stored as unsigned integer types, which are not supported by the convention. After re-casting the variables to a signed data type that was large enough to prevent any data loss, e.g. unsigned 8-bit int -> signed 16-bit int, I was able to successfully import my netCDF files into ArcMap and Pro without issue. 

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AaronFriesz2
New Contributor II

Support for netCDF files in ArcMap and Pro seems to be complete dependent on whether the file is CF compliant. I've heard this before, but thought there might be some wiggle room. When my files are passed through a compliance checker they pass most of the checks except for a couple warnings pertaining the the data type of some the variables. That was the snag. CF conventions dictate that netCDF variable data types can only be char, byte, short, int, float or real, and double. Some of the variables in our files are stored as unsigned integer types, which are not supported by the convention. After re-casting the variables to a signed data type that was large enough to prevent any data loss, e.g. unsigned 8-bit int -> signed 16-bit int, I was able to successfully import my netCDF files into ArcMap and Pro without issue.