File describing the reference data!
============
REF_1_LAN_DK
============
ENVISAT L2 data over Denmark. The columns in the file are
Col 1: Orbit No
Col 2: Latitude
Col 3: Longitude
Col 4: Time (Seconds since January 2000)
Col 5: Surface elevation in m relative to WGS 84 based on ICE1
Col 6: Surface elevation in m relative to WGS 84 based on ICE2

============
REF_2_LAN_DK
============
SARAL/ALTIKA L2 data over Denmark

Col 1: Cycle No
Col 2: Orbit No
Col 3: Year
Col 4: Month
Col 5: Day
Col 6: DecYear, decimal years
Col 7: Latitude
Col 8: Longitude
Col 9: Surface elevation in m relative to Topex/Poseidon based on ICE1
Col 10: Surface elevation in m relative to Topex/Poseidon based on ICE2
Col 11 Geoid

============
REF_3_LAN_DK
============
Surface elevations of selected Danish lakes, based on laser data from
the Danish height model which can be downloaded at http://eng.gst.dk/

Col 1: Lake ID which is given in the shape file lake_dk_large.shp
Col 2: Lake name
Col 3: Surface elevations relative to WGS84