I have a tool that I used to create the San Francisco hightmap. If you want me to grab a real world heightmap, I can do it for you.
Follow these steps
Go to the area that you want the height map, then paste Copy this to Clipboard in a reply to this forum post. I will then paste a link to the files in the forum, allowing everyone to use them.
If you want to know more about the tool I am using, you can buy it here: http://infinity-code.com/en/docs/real-world-terrain
To paste your coordinates into discourse, you need to click the button. See an example below: