afernandezody
Member
Hello,
My questions are related to the parameters for a LCC projection. According to the User Guide, the ref_lat and ref_lon variables specify the latitude and longitude for the center of the coarse domain. Then, you also have truelat1 & 2 (standard latitudes) plus stand_lon (standard longitude), which are described as LCC parameters. However, the LCC decriptions that I have seen use 4 parameters. For example a proj4 string could read something like:
"+proj=lcc +lat_1=33.0 +lat_2=45.0 +lat_0=40.0 +lon_0=-97.0 +datum=WGS84 +no_defs"
Let me parse my questions:
1 - Are we supposed to use the variable ref_lat (from namelist.wps) as the standard latitude (or latitude of origin) for lat_0 in addition to being the center of the coarse domain?
2 - If so, and for a hypothetical case where ref_lon and stand_lon are different (e.g. ref_lon=-78.0, ref_lat = 40.0, stand_lon=-97 ), would that mean that the center of the domain can be displaced (versus the projection) in the east-west direction but not in north-south direction?
3 - Is it possible to use False_easting or False_northing with Geogrid?
Thanks.
My questions are related to the parameters for a LCC projection. According to the User Guide, the ref_lat and ref_lon variables specify the latitude and longitude for the center of the coarse domain. Then, you also have truelat1 & 2 (standard latitudes) plus stand_lon (standard longitude), which are described as LCC parameters. However, the LCC decriptions that I have seen use 4 parameters. For example a proj4 string could read something like:
"+proj=lcc +lat_1=33.0 +lat_2=45.0 +lat_0=40.0 +lon_0=-97.0 +datum=WGS84 +no_defs"
Let me parse my questions:
1 - Are we supposed to use the variable ref_lat (from namelist.wps) as the standard latitude (or latitude of origin) for lat_0 in addition to being the center of the coarse domain?
2 - If so, and for a hypothetical case where ref_lon and stand_lon are different (e.g. ref_lon=-78.0, ref_lat = 40.0, stand_lon=-97 ), would that mean that the center of the domain can be displaced (versus the projection) in the east-west direction but not in north-south direction?
3 - Is it possible to use False_easting or False_northing with Geogrid?
Thanks.