This page lists some common sources for terrain data that can be used with the Pathloss program. Pathloss 4 can only use elevation and imagery data.
NED vs SRTM in North America
In North America there is NED and SRTM. What is the difference? The short answer is the SRTM data tends to include land cover in its data (elevations are the tops of the tree canopy or built up areas), where the NED data tends to be bare earth.
Public Terrain data (Free of charge)
FetchSRTM - Download tool for finding and downloading SRTM, NED and NLCD terrain data.
USGS NED Data
NLCD - USGS National Land Cover Data in BIL format. (USA Only)
NED data in GridFloat format - NED data in GridFloat format
SRTM Data (Worldwide 1" & 3" resolution)
SRTM - USGS site for downloading SRTM elevation data.
SRTM30 - USGS site for downloading SRTM30 which is an upgraded version of GTOPO30 (30" data for the world)
Geobase - Geobase elevation data (CDED), Vector data for roads etc. and satellite imagery for all of Canada.
NED data in GridFloat format - Very convenient FTP access to NED data in GridFloat format. The 1" files cover North America (Canada, USA and Mexico)
Toporama - 1:50,000 scale UTM projected topographic maps for Canada in GeoTiff format.
Viewfinder Panoramas - Excellent resource to download free 3 second data for the world. This data is compiled from SRTM data with voids and artifacts filled in from other sources. See the SRTM section above for instructions on configuring for use in Pathloss.
ASTER - 1 second ASTER Global DEM Version 2.
Global Land Cover Characteristics Data Base (GLCC World) - Global Land Cover Characteristics Data Base Version 2.0 (Clutter database. Pathloss 5 only)
Commercial Terrain data
Most commercial data is supplied in a rectangular projection (e.g UTM). Be sure to specify that the data must be provided in a BIL format. Setup instructions for Version 4 are available at http://www.pathloss.com/downloads/docs/planet_utm.pdf
http://www.siradel.com - 1m to 100m resolution high quality map data available worldwide.
http://geoimage.fr/ - 1m to 100m resolution maps available worldwide.
http://www.infoterra.fr/Infoterra/ - 1m to 100m resolution maps available worldwide.
http://igage.com/ - Igage produces imagery datasets that cover the USA.