Aug 7, 2021

Spatial Georeferencing Himawari-8 Satellite Images

Himawari-8 is a Japanese meteorological satellite that is stationed over East-Asia and Oceania.

Every 10 minutes, it takes a high resolution, full disc image of the earth which you can download from a portal provided by the NICT.

The images are provided in PNG file format and are not georeferenced. If you try to open them in a GIS software package it won't display correctly.

Thankfully this is as easy fix with 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 [corner values]	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 with the rest of your spatial data.

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