<p>I have coordinates obtained from Google Maps (latitude and longitude). I also downloaded a number of NetCDF4 files for different years and months that contain sea surface temperature (SST) from the link below. This data is related to ORAS5 global ocean reanalysis monthly data. <a href="https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-oras5?tab=form" rel="nofollow noreferrer">https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-oras5?tab=form</a></p>
<p>Now I want to extract the sea surface temperature data related to these coordinates from the NetCDF4 files. Datum for Google Maps is WGS84 and Projection is a ”web Mercator”. The projection for the NetCDF4 files is also “Tripolar model grid”.</p>
<p>If I need to change the NC files projection to Web Mercator, how is it done?</p>
<p>In general, what should be done to correctly extract SST data in NetCDF files for Google Maps coordinates?</p>
<p>I also work with Python and MATLAB.</p>

CC BY-SA 4.0
2022-02-10T20:14:53.303Z
I don't think you need to change projection, as the tripolar grid produces longitude-latitude output. The coordinates in the NetCDF files are a mesh of degrees east (nav_lon) and degrees north (nav_lat). You can use Google Earth to find the coordinates you need and then subset the exact location or area indices from nav_lon and nav_lat.
Ingvar Lukas
CC BY-SA 4.0
2022-02-12T00:52:55.083Z
Hi and welcome! What exactly do you mean by "Google Map coordinates"? The NetCDF files already have latitude and longitude coordinates, what else do you need? Could you could explain more about what your end goal?
ouranos
CC BY-SA 4.0
2022-02-12T12:24:31.137Z
Hello and thanks for your attention to my question, I manually extracted a number of coordinates (point) from the coastline of several countries from Google Maps. Now I want to extract the sea surface temperature from the NC files for the odd months from 1980 until now. I have 246 NC files. In NC files, the lat and long variables each have two dimensions! I used to work with a regular one dimension. I'm confused about extraction. How can I extract SST for coordinates?
arman H
<climate><python><netcdf><coordinate-system><projection>
Extract data from NetCDF file with tripolar projection for lat & long coordinates
arman H
# Extract data from NetCDF file with tripolar projection for lat & long coordinates

(Asked by: username_0 on 2022-02-10)

I have coordinates obtained from Google Maps (latitude and longitude). I also downloaded a number of NetCDF4 files for different years and months that contain sea surface temperature (SST) from the link below. This data is related to ORAS5 global ocean reanalysis monthly data. <https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-oras5?tab=form>

Now I want to extract the sea surface temperature data related to these coordinates from the NetCDF4 files. Datum for Google Maps is WGS84 and Projection is a ”web Mercator”. The projection for the NetCDF4 files is also “Tripolar model grid”.

If I need to change the NC files projection to Web Mercator, how is it done?

In general, what should be done to correctly extract SST data in NetCDF files for Google Maps coordinates?

I also work with Python and MATLAB.

**Tags:** climate, python, netcdf, coordinate-system, projection

> **Comments:**
> **username_1**: I don't think you need to change projection, as the tripolar grid produces longitude-latitude output. The coordinates in the NetCDF files are a mesh of degrees east (nav_lon) and degrees north (nav_lat). You can use Google Earth to find the coordinates you need and then subset the exact location or area indices from nav_lon and nav_lat.  
> **username_2**: Hi and welcome! What exactly do you mean by "Google Map coordinates"? The NetCDF files already have latitude and longitude coordinates, what else do you need? Could you could explain more about what your end goal?  
> **username_0**: Hello and thanks for your attention to my question, I manually extracted a number of coordinates (point) from the coastline of several countries from Google Maps. Now I want to extract the sea surface temperature from the NC files for the odd months from 1980 until now. I have 246 NC files. In NC files, the lat and long variables each have two dimensions! I used to work with a regular one dimension. I'm confused about extraction. How can I extract SST for coordinates?  

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## 0 answers

