Changes between Version 6 and Version 7 of Cf2CrsWkt

Timestamp:

10/10/12 13:59:49 (7 years ago)

Author:

etourigny

Comment:

--

Cf2CrsWkt

@@ -165 +165 @@
 ||||||false_northing||false_northing||+y_0||False northing||8807||!FalseNorthing||||
 
-=== '''Notes:''' ===
+=== '''Table Notes:''' ===
 
  1. Multiple CF/WKT translations, see projection-specific translations.
  2. Parameter used in every projection.
  3. See projection-specific notes.
+
+=== Units Information ===
+
+Translation of units depends on if the crs is geographic or projected
+
+For a geographic crs (grid_mapping_name = "latitude_longitude"), units are angular. GEOGCS contains a UNIT node which gives the conversion to radians. When the crs is in degrees the following node is used: UNIT["degree",0.0174532925199433]. For a more complete description, see CT 1.0 section "7.3.19 UNIT"
+CF requires all value to be in degrees, which is specified in the dimension's units attribute ( lon:units = "degrees_east" / lat:units = "degrees_north" ), the udunits packages allows to transform from radians.
+
+For a projected crs, units are linear.  PROJCS must contains a UNIT node which gives the conversion into meters. For example, if the units are in kilometers the following node is used: UNIT["kilometre",1000]].
+In CF, units are given in the dimension's units attribute (xc:units = "m").
 
 === Projection-specific notes ===