Mapproject -T option

Q&A
1

I found a Christmas bug. Need to use mapproject to transform coordinates from a strange GRS-80 based Mollweide projected coordinate system into WGS-84 lon, lats.

As a simple example, try this:

echo "-4725626.3127 -6460896.1797" | gmt mapproject -Jw0/1:1 -R-180/180/-90/90 -C -Fe -I -TGRS-80:0,0,0/- --FORMAT_FLOAT_OUT=%.8f
mapproject [ERROR]: Option -T: Cannot work with -A, -E, -G, -L, -W or -Z

An error response is issued by mapproject. The message doesn’t make sense, since none of the incompatible options were requested in the command line.

2

It’s certainly the :R_ in GRS

C:\v>echo "-4725626.3127 -6460896.1797" | gmt mapproject -Jw0/1:1 -R-180/180/-90/90 -C -Fe -I -TGUS-80:0,0,0
mapproject [ERROR]: Ellipsoid GUS-80 not recognized!

Try the proj4 syntax

3

Fixed in master now. Was a dumb bug not anything to do with GUS which does not exist anyway.

echo “-4725626.3127 -6460896.1797” | gmt mapproject -Jw0/1:1 -R-180/180/-90/90 -C -Fe -I -TGRS-80:0,0,0/- --FORMAT_FLOAT_OUT=%.8f
-67.72575952 -55.93418369

4

Fixed in master now.

5

@pwessel: I assume you refer to this post.

6

probably.

7

Thanks for the fix. Santa came early!

Joaquim, you freaked me out, thinking I was hit with a Christmas typo. Whew. I had it as GRS-80, not GUS-80.

8

What the

1 Like
9

There definitively is a Planet Gus but despite excessive googling I cannot find basic information like flattening.

1 Like
10

must be four elephants standing on the back of a giant turtle then

can gmt hanlde such basic data?

merry Xmas everybody

11

Yep, Merry Christmas and happy New Vear to all GMT users and abusers!