Projection of height with -J

When trying to use the -J option to project height (instead of default, width) with psxy, I get a few errors I’m not understanding.

psxy -Jm36hi …

This gives me the error: “36h not a valid number and may not be decoded properly”

psxy -Jm36ih …

This gives me the errors: " Length h not supported - revert to default unit [cm]", and “36h not a valid number and may not be decoded properly”

-Jm36i works well in setting the width of the projection. How can I make -J set the height?

Append +dh , +du , or +dl to the given width if you instead want to set the map height, the maximum (upper) dimension, or the minimum (lower) dimension, respectively [Default is +dw for width]

There’s a « + »

After adding +dh, I ran into errors still with my input as it was.

What fixed it was using the uppercase M. This was effective in building the height dimension properly:

psxy -JM36i+dh …

Oh yeah, lower case asks for « scale » while uppercase asks for « paper dimension ». It’s the case for all projections I think