5

I notice several EPSG codes in one WKT. At the first glance it almost is non-intuitive to see so many EPSG codes linked to a single EPSG.

Can someone explain each line of the following WKTs for EPSG:5070 and EPSG:4326?

EPSG: 5070

enter image description here

EPSG: 4326

enter image description here

2
5

For a full understanding see the specifications:

https://www.ogc.org/standards/wkt-crs

Interestingly, if you look at the EPSG registry (https://epsg.org/home.html) WKT2 definitions of those two CRS then you see that almost every line has an associated EPSG code

https://epsg.org/crs/wkt/id/5070

PROJCRS["NAD83 / Conus Albers",
  BASEGEOGCRS["NAD83",
    DATUM["North American Datum 1983",
      ELLIPSOID["GRS 1980",6378137,298.257222101,
        LENGTHUNIT["metre",1,ID["EPSG",9001]],
        ID["EPSG",7019]],
      ID["EPSG",6269]],
    PRIMEM["Greenwich",0,
      ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9102]],
      ID["EPSG",8901]],
    ID["EPSG",4269]],
  CONVERSION["Conus Albers",
    METHOD["Albers Equal Area",
      ID["EPSG",9822]],
    PARAMETER["Latitude of false origin",23,
      ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9102]]],
    PARAMETER["Longitude of false origin",-96,
      ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9102]]],
    PARAMETER["Latitude of 1st standard parallel",29.5,
      ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9102]]],
    PARAMETER["Latitude of 2nd standard parallel",45.5,
      ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9102]]],
    PARAMETER["Easting at false origin",0,
      LENGTHUNIT["metre",1,ID["EPSG",9001]]],
    PARAMETER["Northing at false origin",0,
      LENGTHUNIT["metre",1,ID["EPSG",9001]]],
    ID["EPSG",5068]],
  CS[Cartesian,2,
    ID["EPSG",4499]],
  AXIS["Easting (X)",east,
    ORDER[1]],
  AXIS["Northing (Y)",north,
    ORDER[2]],
  LENGTHUNIT["metre",1,ID["EPSG",9001]],
  USAGE[SCOPE["Data analysis and small scale data presentation for contiguous lower 48 states."],AREA["United States (USA) - CONUS onshore - Alabama; Arizona; Arkansas; California; Colorado; Connecticut; Delaware; Florida; Georgia; Idaho; Illinois; Indiana; Iowa; Kansas; Kentucky; Louisiana; Maine; Maryland; Massachusetts; Michigan; Minnesota; Mississippi; Missouri; Montana; Nebraska; Nevada; New Hampshire; New Jersey; New Mexico; New York; North Carolina; North Dakota; Ohio; Oklahoma; Oregon; Pennsylvania; Rhode Island; South Carolina; South Dakota; Tennessee; Texas; Utah; Vermont; Virginia; Washington; West Virginia; Wisconsin; Wyoming."],
  BBOX[24.41,-124.79,49.38,-66.91]],
ID["EPSG",5070]]

https://epsg.org/crs/wkt/id/4326

GEOGCRS["WGS 84",
  ENSEMBLE["World Geodetic System 1984 ensemble",
     MEMBER["World Geodetic System 1984 (Transit)",
       ID["EPSG",1166]],
     MEMBER["World Geodetic System 1984 (G730)",
       ID["EPSG",1152]],
     MEMBER["World Geodetic System 1984 (G873)",
       ID["EPSG",1153]],
     MEMBER["World Geodetic System 1984 (G1150)",
       ID["EPSG",1154]],
     MEMBER["World Geodetic System 1984 (G1674)",
       ID["EPSG",1155]],
     MEMBER["World Geodetic System 1984 (G1762)",
       ID["EPSG",1156]],
     ELLIPSOID["WGS 84",6378137,298.257223563,
      LENGTHUNIT["metre",1,ID["EPSG",9001]],
      ID["EPSG",7030]],
     ENSEMBLEACCURACY[2],
    ID["EPSG",6326]],
  PRIMEM["Greenwich",0,
    ANGLEUNIT["degree",0.0174532925199433,ID["EPSG",9102]],
    ID["EPSG",8901]],
  CS[ellipsoidal,2,
    ID["EPSG",6422]],
  AXIS["Geodetic latitude (Lat)",north,
    ORDER[1]],
  AXIS["Geodetic longitude (Lon)",east,
    ORDER[2]],
  ANGLEUNIT["degree (supplier to define representation)",0.0174532925199433,ID["EPSG",9122]],
  USAGE[SCOPE["Horizontal component of 3D system."],AREA["World."],
  BBOX[-90.00,-180.00,90.00,180.00]],
ID["EPSG",4326]]

You can look-up the respective codes in the registry for example EPSG",9122 is a transformation (NAD83(CSRS)v2 to NAD83(CSRS)v4 (1)): https://epsg.org/transformation/wkt/id/9122

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.