Africa

Monthly precipitation in Africa.
QGIS
GIMP
Published

November 8, 2023

Monthly precipitation in Africa

Exploring Worldclim data further.

Monthly precipitation in Africa, 1970 to 2000.

Monthly precipitation in Africa, 1970 to 2000.

Data

Downloaded historic precipitation data from https://worldclim.org/data/worldclim21.html

Units are mm. A raster layer for each month. Aggregated data for 1970 to 2000.

Data described in:

Fick, S.E. and R.J. Hijmans, 2017. WorldClim 2: new 1km spatial resolution climate surfaces for global land areas. International Journal of Climatology 37 (12): 4302-4315.

Information about Bioclimatic variables

Tools

  • QGIS.
  • GIMP image editing software.

Process

To prepare data:

  • Added continent data and selected just Africa. Exported to new GeoPackage layer.
  • Reprojected precipitation data for each month to ESRI:102022 - Africa Albers Equal Area Conic.
  • Clipped each months raster data to mask using the Africa layer as the mask.
  • Styled the first layer with Singleband Pseudocolour using Blues ramp. Used highest value from combined layers - 1,500 mm.
  • Copied and pasted style to all layers.

Set up a layout, then exported an image for each month.

Creating animation

Used GIMP to create an animated GIF.

  • Reduced size of monthly images to keep animation size smaller. Make a note of the size in pixels.
  • Create a new canvas - File > New then enter correct size and orientation. Set resolution under Advanced.
  • Add images as “frames” starting with the first image at the “bottom” of the layers.
    • Can just drag and drop images in and each one is added as the next layer up.
  • Remove blank background layer - unless you want a plain white frame in your animated gif!
  • Save!
  • To keep size down you can use an indexed colour mode instead of RGB. Image > Mode > Indexed. Stick to defaults for now!
  • File > Export As - give file name .gif extension.
  • In dialog select As animation and choose options.
    • Frame disposal should be set to One frame per layer (replace)
    • Tick both Use delay entered above for all frames and Use disposal entered above for all frames.
    • Change Delay as required to change speed of animation, e.g. 1000 milliseconds for a fairly stately pace!
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