Where to get Terrain Data - both free and paid?

Question

Where can you get terrain data? What resolution data can you get for free? What resolution data can you get when you buy the data? How much is that data? I found this site that has free terrain data. The resolution is 30m x 30m. Is that the best that can be found for free?

Answer 1

The 30m-accuracy data set is from the NASA Global Digital Elevation Model which was open sourced in June. It is derived from thermal imaging data and the accuracy figure is conservative, in practice a lot of the time, if there is not too much vegetation, accuracy is better. Here is an example of an output generated by the ASTER GDEM for Death Valley, CA:

Answer 2

The best available free terrain data for Canada is from Geobase CDED. The elevation data is split into tiles based on the National Topographic System (NTS) which is analogous with the USGS quadrangle grids. The pixel dimensions are ~15 and ~90 metres for 1:50K and 1:250k scale data respectively.

I mosaicked the 50k CDED and put it online, intro page for that effort is here

A low resolution (~900m) national model called Canada3D can be nabbed from GeoGratis

A more comprehensive list of Canadian elevation data can be found at http://www.vterrain.org/Locations/ca/

@RED SOFT ADAIR-StefanWoe - you asked about Germany, see http://www.vterrain.org/Locations/de/

Answer 3

From the National Elevation Dataset.

Answer 4

Also look at the USGS: http://seamless.usgs.gov/index.php

It looks like they have 10m x 10m resolution for the US.

Answer 5

I successfully retrieved digital elevation model (dem) data from two web sites.

WebGIS has free 30mx30m resolution data.

MapMap had 10mx10m resolution data for $5 per data quad (about 10km x 10 km area). The minimum order is $15 though. So, if you want to go this route, you need to purchase 3 quads worth of data.

This web site has information about DEM files including the file format spec.

There are suppose to be web sites that offer the 10m resolution data for free (like this one) but I couldn't find the links to the free downloads.

Next, I want to get aerial imagery for the data I downloaded. When I figure that out, I'll post that information.