diff --git a/docs/Users_Guide/data_io.rst b/docs/Users_Guide/data_io.rst index 03d7ab02e..bc67895b9 100644 --- a/docs/Users_Guide/data_io.rst +++ b/docs/Users_Guide/data_io.rst @@ -22,7 +22,7 @@ Tropical cyclone forecasts and observations are typically provided in a specific Requirements for CF Compliant NetCDF ------------------------------------ -The MET tools use following attributes and variables for input CF Compliant NetCDF data. +The MET tools use following attributes and variables for input "`CF Compliant NetCDF data `_". 1. The global attribute "Conventions". @@ -30,7 +30,7 @@ The MET tools use following attributes and variables for input CF Compliant NetC 3. The "`coordinates `_" attribute for the data variables. It contains the coordinate variable names. -4. The "`grid_mapping `_" attribute for the data variables for projections and the matching grid mapping variable (optional for the latitude_longitude projection). +4. The "`grid_mapping `_" attribute for the data variables for projections and the matching grid mapping variable (optional for latitude_longitude and rotated_latitude_longitude projections). 5. The gridded data should be evenly spaced horizontally and vertically. @@ -78,7 +78,7 @@ Here are examples for the grid mapping variable ("edr" is the data variable): grid_mapping:GRIB_earth_shape = "spherical" ; grid_mapping:GRIB_earth_shape_code = 0 ; -When the grid mapping variable is not available, MET detects the latitude_longitude projection in following order: +When the grid mapping variable is not available, MET can detect either a latitude_longitude or rotated_latitude_longitude projection. It detects the latitude_longitude projection in the following order: 1. the lat/lon projection from the dimensions @@ -98,6 +98,16 @@ MET gets the valid time from the time variable and the "forecast_reference_time" 2. TRMM_3B42_daily_filename (3B42_daily...
.7.G3.nc) +For rotated_latitude_longitude projections, MET detects the projection using the following logic: + +1. Looking for a variable that has the same name as a dimension. + +2. If a variable is found, checking to make sure the variable has a standard name attribute and that that attribute is not empty. + +3. Checking to see if the standard name attribute is called grid_latitude for latitude variables and grid_longitude for the longitude variable. + +The latitude and longitude variables must be one dimensional and with their size matching the corresponding dimension for latitude_longitude and rotated_latitude_longitude grids. + .. list-table:: Valid strings for the "units" attribute. :widths: auto :header-rows: 1