Rotating an image on PYGMT

Q&A PyGMT Q&A
1

Hi everyone. I need to insert an image to the map but I need to rotate the image. The position is like a rotated rectangular. Do you know how can I do it on PYGMT?

Thanks

2

Hello @mtabbakhha,

you can inset figures in PyGMT using the pygmt.Figure.image method. To rotate the image you can play with the perspective parameter. For details please have a look at the documentation pygmt.Figure.image — PyGMT.

Below you find a slightly modified PyGMT gallery example:

# source: https://www.pygmt.org/latest/gallery/images/image.html#sphx-glr-gallery-images-image-py
# last access: 2022/11/09

import os

import pygmt

fig = pygmt.Figure()
fig.basemap(region=[0, 2, 0, 2], projection="X10c", frame=True)

# place and center the GMT logo from the GMT website to the position 1/1
# on a basemap, scaled up to be 3 cm wide and draw a rectangular border
# around the image
fig.image(
    imagefile="https://www.generic-mapping-tools.org/_static/gmt-logo.png",
    position="g1/1+w3c+jCM",
    box=True,
    # select perspective
    # set the azimuth and elevation angle of the viewpoint
    # Default is [180, 90]
    perspective=[90, 90],  # <<< can be used to rotate the image
)

# clean up the downloaded image in the current directory
os.remove("gmt-logo.png")

fig.show()

output figure with rotation:

rotated_figure
rotated_figure1283×1248 14.4 KB

1 Like
3

thanks so much. I have a rectangular image. I want to place the four corner of the rectangle to the four corner of gps location. Is there any way to do that?

4

You calculate the angle, aka the azimuth, between the « north of the plot » and the « north of your gps data » and you apply that to the perspective parameter exactly like @yvonnefroehlich explained above.