Skip to content

Matrix grid doesn't always work with different central meridians #4335

@seisman

Description

@seisman

Description of the problem

The issue was first reported in GenericMappingTools/pygmt#390, but was thought to be fixed by GMT PRs #3813 and #3829. The GMT master branch works for some projection parameters but doesn't always work.

Full script that generated the error

import pygmt
fig = pygmt.Figure()

fig.grdimage("@earth_relief_01d_g", projection="Q123/0/15c", cmap="geo")

fig.shift_origin(yshift="8c")

dem = pygmt.datasets.load_earth_relief(resolution="01d", registration="gridline")
fig.grdimage(dem, projection="Q123/0/15c", cmap="geo")
fig.savefig("map.pdf")

Output

image

Image difference
image

In the PyGMT, we test several different projection parameters. Here are the ones that are known to fail:

  • Q123/0/15c
  • Q123/30/15c
  • Q180/0/15c
  • Q180/30/15c

Here are the ones that are known to work:

  • Q0/0/15c
  • Q0/30/15c

The same parameters work well for General Stereographic projection (i.e., changing Q to S).

Note: Those tests were originally written by @weiji14.

Metadata

Metadata

Assignees

Labels

bugSomething isn't working

Type

No type

Projects

No projects

Milestone

Relationships

None yet

Development

No branches or pull requests

Issue actions