Data type changes when exporting and re-loading data

[Nick-Maurer]

I'm not sure if this is an issue with write_dataset_to_netcdf or with xarray's xr.open_dataset, but as you can see in the screen shot the data changes type. This messes with the masking functions, as they are built to expect integers.

[Kirill888]

@Nick-Maurer please report generated netcdf header information.

ncdump -hc <FILE>

[Nick-Maurer]

Not sure what is classed as header info, but here is the full output:

netcdf wo_data_1988-02 {
dimensions:
    time = 2 ;
    y = 3735 ;
    x = 4485 ;
variables:
    double time(time) ;
        time:units = "seconds since 1970-01-01 00:00:00" ;
        time:standard_name = "time" ;
        time:long_name = "Time, unix time-stamp" ;
        time:axis = "T" ;
        time:calendar = "standard" ;
    double y(y) ;
        y:units = "metre" ;
        y:standard_name = "projection_y_coordinate" ;
        y:long_name = "y coordinate of projection" ;
    double x(x) ;
        x:units = "metre" ;
        x:standard_name = "projection_x_coordinate" ;
        x:long_name = "x coordinate of projection" ;
    int spatial_ref ;
        spatial_ref:grid_mapping_name = "albers_conical_equal_area" ;
        spatial_ref:standard_parallel = -18., -36. ;
        spatial_ref:longitude_of_central_meridian = 132. ;
        spatial_ref:latitude_of_projection_origin = 0. ;
        spatial_ref:false_easting = 0. ;
        spatial_ref:false_northing = 0. ;
        spatial_ref:long_name = "GDA94 / Australian Albers" ;
        spatial_ref:semi_major_axis = 6378137. ;
        spatial_ref:semi_minor_axis = 6356752.31414036 ;
        spatial_ref:inverse_flattening = 298.257222101 ;
        spatial_ref:crs_wkt = "PROJCS[\"GDA94 / Australian Albers\",GEOGCS[\"GDA94\",DATUM[\"Geocentric_Datum_of_Australia_1994\",SPHEROID[\"GRS 1980\",6378137,298.257222101,AUTHORITY[\"EPSG\",\"7019\"]],AUTHORITY[\"EPSG\",\"6283\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AUTHORITY[\"EPSG\",\"4283\"]],PROJECTION[\"Albers_Conic_Equal_Area\"],PARAMETER[\"latitude_of_center\",0],PARAMETER[\"longitude_of_center\",132],PARAMETER[\"standard_parallel_1\",-18],PARAMETER[\"standard_parallel_2\",-36],PARAMETER[\"false_easting\",0],PARAMETER[\"false_northing\",0],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],AXIS[\"Easting\",EAST],AXIS[\"Northing\",NORTH],AUTHORITY[\"EPSG\",\"3577\"]]" ;
        spatial_ref:spatial_ref = "PROJCS[\"GDA94 / Australian Albers\",GEOGCS[\"GDA94\",DATUM[\"Geocentric_Datum_of_Australia_1994\",SPHEROID[\"GRS 1980\",6378137,298.257222101,AUTHORITY[\"EPSG\",\"7019\"]],AUTHORITY[\"EPSG\",\"6283\"]],PRIMEM[\"Greenwich\",0,AUTHORITY[\"EPSG\",\"8901\"]],UNIT[\"degree\",0.0174532925199433,AUTHORITY[\"EPSG\",\"9122\"]],AUTHORITY[\"EPSG\",\"4283\"]],PROJECTION[\"Albers_Conic_Equal_Area\"],PARAMETER[\"latitude_of_center\",0],PARAMETER[\"longitude_of_center\",132],PARAMETER[\"standard_parallel_1\",-18],PARAMETER[\"standard_parallel_2\",-36],PARAMETER[\"false_easting\",0],PARAMETER[\"false_northing\",0],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],AXIS[\"Easting\",EAST],AXIS[\"Northing\",NORTH],AUTHORITY[\"EPSG\",\"3577\"]]" ;
        spatial_ref:GeoTransform = 1762560., 30., 0., -3017700., 0., -30. ;
    ubyte water(time, y, x) ;
        water:_FillValue = 1UB ;
        water:grid_mapping = "spatial_ref" ;
        water:units = "1" ;

// global attributes:
        :date_created = "2024-05-20T05:29:18.575874" ;
        :Conventions = "CF-1.6, ACDD-1.3" ;
        :history = "NetCDF-CF file created by datacube version \'1.8.18\' at 20240520." ;
        :coordinates = "spatial_ref" ;
        :geospatial_bounds = "POLYGON ((149.9892826763886 -26.70206653307046, 150.13318516437332 -27.584615580444392, 150.15067994131257 -27.69094499164086, 151.1654933746167 -27.561225446527214, 151.51555238448833 -27.51478041075792, 151.3608565800874 -26.63362302607288, 151.34237987930615 -26.527417677862754, 150.33713377672046 -26.65842082410779, 149.9892826763886 -26.70206653307046))" ;
        :geospatial_bounds_crs = "EPSG:4326" ;
        :geospatial_lat_min = -27.6909449916409 ;
        :geospatial_lat_max = -26.5274176778628 ;
        :geospatial_lat_units = "degrees_north" ;
        :geospatial_lon_min = 149.989282676389 ;
        :geospatial_lon_max = 151.515552384488 ;
        :geospatial_lon_units = "degrees_east" ;
}

[Kirill888]

@Nick-Maurer from this we can tell that water is stored as ubyte, so correct format for the original data, so issue is with xarray or netcdf handling of ubyte data types at load time.