Georeferencing Himawari-8
Himawari-8 is a Japanese meteorological satellite that is positioned over East-Asia and Oceania.
It takes a high resolution, full disc image of the earth every 10 minutes which you can download from a portal provided by the NICT.
However, as the images are png files, they are not georeferenced meaning if you open them with a GIS software package they will not be positioned correctly.
This is easy to fix by using gdal_translate.
gdal_translate \
-a_srs "+proj=geos +h=35785863 \
+ellps=WGS84 \
+lon_0=140.7 \
+no_defs" \
-a_ullr -5500000 5500000 5500000 -5500000 \
himawari_8.png himawari_8_registered.tif
| Argument | Description |
|---|---|
| -a_srs | Assign a Spatial Reference System |
| proj=geos | Geostationary projection |
| +ellps=WGS84 | Ellipsoid to use |
| +h=35785863 | Himawari altitude |
| +lon_0=140.7 | Himawari longitude |
| +a_ullr -5500000 5500000 5500000 -5500000 | Corner coordinates of the image |
To calculate the corner values, use this formula
image_resolution / 2 * spatial_resolution
The images are 11,000 pixels and the spatial resolution is 1000m a pixel
11000 / 2 * 1000 = 5,500,000m
If you open the tif file in your GIS package and it will be aligned correctly.
If you wish to reproject to the WGS84 Geographic Coordinate System you can do so with gdal_warp
gdalwarp \
-t_srs "+proj=latlong +ellps=WGS84" \
-wo SOURCE_EXTRA=100 \
himawari_8_registered.tif himawari_8_4326.tif