Problem with azimutha equidistant projection

Q&A
1

Hello,

I am trying to make an azimuthal equidistant projection centered on an epicenter, but limited to distances less than 90 degrees from that epicenter.

I cannot figure out how to do it.
I can get the whole earth by doing

gmt pscoast -P -R-180/180/-90/90 -JE-175.4/-20.5/4i -B30g30 -W0.4p,0/0/0 -G235/200/180 -Dl -V -X1.5 -Y1.0> GMT.ps

(It will plot centered on Tonga), but if I restrict the latitude field in -R to 0/90 :
gmt pscoast -P -R-180/180/0/90 -JE-175.4/-20.5/4i -B30g30 -W0.4p,0/0/0 -G235/200/180 -Dl -V -X1.5 -Y1.0> GMT.ps

it will plot the same map.

Thanks for any suggestion.

Emile

2

Hi @emile

Welcome to the GMT forum!

You need to specify an horizon in the projection.

gmt coast -R-180/180/0/90 -JE-175.4/-20.5/90/4i -B30g30 -W0.4p,0/0/0 -G235/200/180 -Dl -png tonga

tonga
tonga1206×1206 54.3 KB

3

Dear Federico,
yes, it works!

Many thanks/Merci beaucoup/Muchas gracias/Grazie tante/Muito obrigado/Danke schönn/Teşekkur/Спасибо большое/Дякую/Ďakujem pekne/Kõszenem szépen/Dziękuję/Mauururu/Mahalo/շնորհակալություն/谢谢/ありがとう/شكرًا

Emile