Converting Japan DEM GML/XML files to geotiffs

When downloading 5m or 10m DEM data for Japan from their Geospatial Information Authority, you get a bunch of zipped .xml files.

➜ unzip -l
  Length      Date    Time    Name
---------  ---------- -----   ----
   733439  2016-09-14 23:05   FG-GML-6645-42-05-DEM5A-20161001.xml
   587112  2016-09-14 23:05   FG-GML-6645-42-06-DEM5A-20161001.xml
   685434  2016-09-14 23:05   FG-GML-6645-42-07-DEM5A-20161001.xml
    86624  2016-09-14 23:05   FG-GML-6645-42-15-DEM5A-20161001.xml
   555112  2016-09-14 23:05   FG-GML-6645-42-16-DEM5A-20161001.xml
---------                     -------
  2647721                     5 files

Inspecting these .xml files shows they do contain the elevation data as newline-separated tuples, but they’re not readable by common tools like GDAL. This stackoverflow question suggests using demtool but it only runs on windows.

So I built a tool jpgis-dem to convert these .xml files to .tif. It uses the same logic as tmizu23/demtool but written in Python (with rasterio) so you can run it on Linux and MacOS.

It installs with pip

pip install jpgis-dem

and can convert .xml files

jpgis-dem xml2tif FG-GML-3622-57-DEM10B-20190510.xml 3622-57.geotiff

as well as zipped archives containing one or more .xml files

jpgis-dem xml2tif 3624-31.geotiff

into cloud-optimized geotiff files that can be opened by e.g., qgis. Here’s a heatmap for a single tile:

Elevation heatmap