Download and Convert DEMs of Japan from the Japanese Geospatial Information Authority
The Geospatial Authority of Japan offers some of the best DEMs of Japan I’ve been able to find. (If you have tips for any others, please let me know!) That said, the website and download process is not as straightforward as what I’m used to from the USGS, and for people hoping to use the data in QGIS or other GIS programs, the data needs a significant amount of processing to get it into a format you can use. If you’re looking DEMs of Japan however, they seem to be the best game in town. Here’s how to get what you need.
To download the DEMs you’ll need to go to the geospatial information authority’s website (https://fgd.gsi.go.jp/download/menu.php). You’ll need to create an account, and sign in. I created my account a while ago, and don’t remember the exact details, but Google Chrome will automatically translate the pages for you if you don’t read Japanese, so you should be able to get on well enough.
After you provide them with your personal information, they’ll send you an email with your username and password (in plain text, in the body of the email). After spending a couple minutes thinking about that, you can use those credentials to sign in.
Next, chose the resolution you’re after, and the area you’re interested in- in that order. Once you make a tile selection they won’t let you change resolutions.
Then hit the button to confirm your download.
You’ll arrive at a page that looks like this. Every time I’ve done this, there have been multiple pages of files to download. You might be tempted to click “check all” then go to the next page and repeat the process so you can download all the files at once, but that maneuver will lead to nothing but sadness — checked files are immediately unchecked when you switch to the next page.
The fastest way to download the files (that I’ve found) is to click the button to download all the files on this page. Then wait for the first page-worth of files to download. At this point the downloaded files will be automatically deleted from the list and you can, without clicking next page, click that same button again, and wait for the next batch to download. Repeat this until you have all your files. Why there is no bulk-download button I have no idea.
Now your files should be sitting comfortably in zip files on your hard drive, and we’re ready for the fun to begin.
The DEMs will come as a special, Japan-exclusive JPGIS-formatted XML file. (More information here: https://ja.wikipedia.org/wiki/JPGIS, Japanese). Because of their format, you can’t open the DEMs directly in QGIS. They’ll need to be converted.
There are a couple tutorials that show you how to convert JPGIS files with python, (See here: https://tm23forest.com/contents/python-jpgis-gml-dem-geotiff, Japanese) but I couldn’t get good results. Most people seem to recommend using a program called Ecoris to convert the JPGIS XML files to TIFFs. Ecoris is Windows-only, so you’ll either need to have a Windows computer or run Windows on your mac. If you’re going to go that route, you might find this tutorial helpful: https://medium.com/macoclock/how-to-install-windows-10-on-m1-macs-d0f7ff86d268.
After that, you can grab a copy of Ecoris here: https://www.ecoris.co.jp/contents/demtool.html (get ready for some fun web design). Once again, I recommend Google Chrome/Translate if you don’t read Japanese, or don’t feel like learning a lot of very specific kanji.
Once you download and extract Ecoris, click on convert_and_merge.vbs. Follow the prompts on screen (these are in English). Ecoris does warn you but it bears repeating, make sure you aren't trying to merge layers in JGD2011 and JGD2000 projections (for example 10m and 5m DEMs). You'll need to specify the projection you want (LatLong, UTM, or Plane Rectangular Coordinate) and depending on which of those you specify, a UTM zone or Coordinate Plane Number. Finally decide if you'd like your no-data value set at 0 or -999, and whether you'd also like it to generate a hillshade for you.
The program will run for a few moments, and output each file as it’s own TIF, as well as a merged TIF and, depending on what you selected earlier, a hillshade image.
From there, you can import your layers into QGIS, and make your map.
It goes without saying, but before you use the Geospatial Information Authority data, make sure you check their terms and conditions.
