Terrain2STL

A web-based service that converts publicly available HGT files to useful STL files.

Try it Out!

This project is running on a Google Compute Engine server at jthatch.com. It's updated soon after any commit to this repository.

You can also download everything here and start the server with:

node terrainServer.js

It will run at localhost:8080.

To run without static file serving (only needed if you're using another static file server such as NGINX), start with static serving disable:

NOSTATIC=true node terrainServer.js

A few .HGT files are included, but not the whole set. You can get the rest from the USGS, or I could send you few.

Install

Build the STL generator program with a simple make:

you@comp:~/.../Terrain2STL$ make

If that's successful, generate a test STL with

./celevstl 44.1928 -69.0851 40 40 1.7 0 1 3 1 test.stl

and you should be treated with a model of scenic Rockport harbor!

The arguments here are:

Northwest corner latitude
Northwest corner longitude
Model width ("pixels")
Model height ("pixels")
Vertical scaling factor
Rotation angle (degrees)
Water drop (mm) (how much the ocean should be lowered in models)
Base height (mm) (how much extra height to add to the base of model)
Step size (hgt cells per model pixel)
Output file name

Web Interface

To run the web interface to Terrain2STL, you'll need Nodejs. With that installed, first run install all the necessary node packages with

you@comp:~/.../Terrain2STL$ npm install

Once all the packages are install, start up the server with

you@comp:~/.../Terrain2STL$ node terrainServer.js

and the website should be up localhost:8080/!

To get the Google Maps view to load, you'll need to get a (free) Google Maps API key - see here. Once you have your key, copy example.include-maps.js to include-maps.js and replace the GOOGLE_API_KEY string with your own API key.

To-Do List

Add a resolution slider ~~Box size is in multiples of 120, so allowable downscales are 2,3,4,5,6,8,..~~ Actually DEM resolution is 1/3, allowable downscales are 2,4,5,8 Probably 1/8 resolution is minimum desirable
Draw the northern and southern boundaries of the data set
Add a negative version for molds
Make a manifold surface option (bigger file, but better performance)

Descriptions of Files

/hgt_files
- This directory contains some sample HGT files for testing. Included are Mt. Everest; Rockport, Maine; and San Franciso Bay.
- The whole dataset is 40GB, so only a few files are included.
- This could also be a made a symbolic link to another directory that contains your collection of HGT files
/src
- This is the source code for the part of the program that actually creates the STL files
- /src/elevstl.c - STL-creation program. Accept command line arguments
terrain2stl-proto.html
- The prototype for the HTML source of the website. Must be edited to contain API keys.
terrainServer.js
- Node.js server. Takes parameters from the HTML page and passes them to elevstl to create the STL.
- Also handles client downloading of pages and files.

Done

(Previously on to-do list)