pygmt.Figure.colorbar(Q=True) 10^p annotation

Q&A PyGMT Q&A
1

Hi,

I am wondering if there is a way to annotate a logarithmic colorbar with annotations in the format 10^x? I have made a logarithmic cpt with

pygmt.makecpt(series = [10,16], 
                  cmap = 'lajolla', log=True, no_bg = True)

and then I plot a colour scale with

fig.colorbar(Q = True, frame = 'a1')

The resulting colorbar looks like this, with annotations that are not really user-friendly. It would be nicer if it were 10^10, 10^11 etc (perhaps even including superscripts!).

image
image1382×144 23.5 KB

Am I missing a gmt.conf option or a frame (-B) option to change this format?

Output of pygmt.show_versions() for reference:

PyGMT information:
  version: v0.5.0
System information:
  python: 3.8.10 | packaged by conda-forge | (default, May 10 2021, 22:58:09)  [Clang 11.1.0 ]
  executable: /Applications/anaconda3/envs/pygmt/bin/python
  machine: macOS-10.14.6-x86_64-i386-64bit
Dependency information:
  numpy: 1.19.1
  pandas: 1.1.1
  xarray: 0.16.0
  netCDF4: 1.5.7
  packaging: 20.4
  ghostscript: 9.22
  gmt: 6.2.0rc1
GMT library information:
  binary dir: /Applications/anaconda3/envs/pygmt/bin
  cores: 8
  grid layout: rows
  library path: /Applications/anaconda3/envs/pygmt/lib/libgmt.dylib
  padding: 2
  plugin dir: /Applications/anaconda3/envs/pygmt/lib/gmt/plugins
  share dir: /Applications/anaconda3/envs/pygmt/share/gmt
  version: 6.2.0

Thanks!
Tom

2

Note for anyone who finds this, the solution is to append ‘p’ to the stride in the frame specification (e.g. frame = ‘a1p’), as shown in https://docs.generic-mapping-tools.org/dev/reference/options.html#cartesian-log10-axes