[idvusers] Projection Parameters: semi_major_axis and semi_minor_axis

Hi all,

I am trying to position a radar image with coordinate variables x and y, and additional coordinate variables lat and lon in IDV. The x and y are the projected coordinate variables, lat and lon are the additional coordinate variables.

I noticed that when I use Conventions=CF-1.2, IDV uses the x and y coordinate variables in combination with the projection parameters. With Conventions=CF-1.4, IDV uses the lat/lon coordinate variables.

My polar stereographic radar image is shifted to the south for 0.1 degrees when using CF-1.2 conventions. In this case the X and Y coordinate variables are used. When I use the additional coordinate variables lon and lat, the image is projected correctly. It seems that my projection parameters are not correct or that IDV does not support all the projection parameters I provided. I was wondering whether IDV supports the CF semi_major_axis and semi_minor_axis attributes?

Thank you already,
Maarten Plieger

PS: The projection parameters are:
               projection:grid_mapping_name = "polar_stereographic" ;
               projection:latitude_of_projection_origin = 90. ;
               projection:straight_vertical_longitude_from_pole = 0. ;
projection:scale_factor_at_projection_origin = 0.933012709177451 ;
               projection:false_easting = 0. ;
               projection:false_northing = 0. ;
               projection:inverse_flattening = 298.1833 ;
               projection:semi_major_axis = 6378140. ;
               projection:semi_minor_axis = 6356750. ;
projection:proj4_params = +proj=stere +lat_0=90 +lat_ts=90 +lon_0=0 +k=0.933012709177451 +x_0=0 +y_0=0 +a=6378140 +b=6356750 +units=m"

Maarten Plieger
KNMI, R&D Information and Observation Technology, De Bilt
(t) +31 30 2206330