I'm trying to redefine the Winkel I projection using the Custom Projection option in QGIS to define the central meridian as -100 (100 degrees west) and the latitude of origin as 40 degrees north. I'm assuming if I got the parameters right it would centre my world map on the USA?
I've tried copying the existing Winkel I parameters and adjusting +long_0 to -100 and +lat_ts to 40 but I keep getting a "not valid" message? What am I doing wrong?
With the following WKT definition, I get a valid Winkel 1 projection centered at x=-100, y=40 degrees:
PROJCRS["unknown",
BASEGEOGCRS["unknown",
DATUM["World Geodetic System 1984",
ELLIPSOID["WGS 84",6378137,298.257223563,
LENGTHUNIT["metre",1]],
ID["EPSG",6326]],
PRIMEM["Greenwich",0,
ANGLEUNIT["degree",0.0174532925199433],
ID["EPSG",8901]]],
CONVERSION["unknown",
METHOD["Winkel I"],
PARAMETER["Longitude of natural origin",-100,
ANGLEUNIT["degree",0.0174532925199433],
ID["EPSG",8802]],
PARAMETER["Latitude of 1st standard parallel",40,
ANGLEUNIT["degree",0.0174532925199433],
ID["EPSG",8823]],
PARAMETER["False easting",0,
LENGTHUNIT["metre",1],
ID["EPSG",8806]],
PARAMETER["False northing",0,
LENGTHUNIT["metre",1],
ID["EPSG",8807]]],
CS[Cartesian,2],
AXIS["(E)",east,
ORDER[1],
LENGTHUNIT["metre",1,
ID["EPSG",9001]]],
AXIS["(N)",north,
ORDER[2],
LENGTHUNIT["metre",1,
ID["EPSG",9001]]]]
Result - for the streched shapes, see here QGIS Vector layer stretched across entire map
