• Currently 5.0/5 Stars.
• 1
• 2
• 3
• 4
• 5

I'm still working the details of this one out. But here's what I've found so far. Say you want to get a height map of a real area on earth, and then use it to model the place in a 3d tool like blender. (google earth already maps elevation to satellite imagery automatically -- but doesn't give you the control you can get with a dedicated software package like blender.)

Seamless Data Distribution Delivery from the USGS

http://seamless.usgs.gov/

The USGS has a really nifty tool for downloading data about the earth. It's a bit cryptic to figure out. "Images" that you can download come in a variety of funky multi-part files. Options for format are things like: GeoTiff, ArcGrid, BIL and GridFloat. So how do you get the data into something your average monkey can use?

Since my goal is simply to get the data into grayscale format to create a height map for use in 3d, I experimented with the formats and found that .bil worked the best in conjunction with microdem (freeware) to convert to something more useful. For some reason GeoTiff kept crashing microdem for me. It is supposed to work, but wasn't, so I just stuck with .bil format.

On the "seamless" tool, you basically select an area to download, then review your download format options, then proceed to get your download in the formats you've specified. Takes a bit of playing with to get all the settings right.

Microdem

Once an image is in microdem, you can choose to view heights as grayscale, and then export to photoshop readeable, like bmp. (Microdem is PC only - there might be something similar for mac/nix systems, but I didn't find it right away.)

http://www.usna.edu/Users/oceano/pguth/website/microdem.htm

To get .bil format into, and out of microdem:

• file > open dem
• select the .bil file in the folder of your download from usgs
• modify > elevation > grayscale
• modify > grid > neither
• file > save image > .bmp format

This got me my bmp version of the height map. For the satellite image itself, the only option for download from the seamless tool was ArcGrid, and that was crashing microdem. Since I wasn't able to successfully grab a nice hirez image from seamless in a format that I could convert, I ended up taking an image from google earth, instead.

To line the two up, I did all my selections based on coordinates (see below.)

Blender

Last, we have a nice tutorial on using a grayscale height map to create a landscape in blender available here:

blender landscape tutorial by Olivier Saraja

Note on using Coordinates

On the seamless tool from usgs, it's efficient to download data based on coordinates, rather than selecting an area manually each time. It's faster, and consistent, and you can map it to imagery from another source based on numbers. For Stafford Lake disc golf course I used:

• Top: 38 07 32.00 N
• Bottom: 38 05 57.00 N
• Right: 122 37 15.00 W
• Left: 122 40 08.00 W

To download via coordinates, use the keyboard/xz icon tool in the downloads section of the toolbar, and then enter your coords.

Then, I could add "my places" (markers) to google earth with the exact same coordinates. This was handy for lining up an image file from google earth with a height map from usgs.

Now, I have a nice image from google earth, and a height map from usgs, both aligned to each other based on common coordinates. Onto blender to build a 3d model of the course ...