Free Elevation Data Sources to Use in Global Mapper
Finding data can sometimes be one of the most challenging parts of starting a GIS project. Once the data has been acquired, loading it into Global Mapper is easy – it has the most extensive list of compatible file types for a GIS software anywhere! Elevation data is typically offered as a raster which often represents the Earth’s surface, or bathymetric data can represent the surface below the water as well. These rasters can sometimes come as Digital Terrain Models (DTM) with only the ground represented, or as Digital Surface Models (DSM) that also represent buildings, vegetation, and everything on the earth’s surface. Most modern elevation raster data is generated from lidar. Downloading lidar instead of raster data lets you take more control over the elevation being represented in the dataset. Global Mapper can help you classify, improve, and create gridded layers from lidar to best suit your project’s needs. To help you get started, here are a few popular sources for free elevation data.
Tip: Want to take your elevation data into the field, or stream it on the go? Try Global Maper Mobile.
First, the Online Data tool is the simplest way to find data for Global Mapper. Along with other vector and imagery sources, elevation data can be streamed as terrain and lidar data in multiple formats. Most of the data is streamed from freely available sources such as STRM, the USGS National Map and others which will automatically open in your default browser. The benefit of opening these web portals through Global Mapper is that it will automatically pan the map to match the data extent already open in your Global Mapper workspace. Higher-resolution data can also be purchased from Intermap NEXT map (terrain) or USGS Amazon S3 (Lidar). Once loaded into your workspace, the data can be exported and saved on your machine to be used in Global Mapper’s terrain editing toolset. Found a server that we don’t host? You can add it to your Global Mapper with the Add Custom Sources option. For more information, check out this other blog on Working with Online Data in Global Mapper.
Listed as one of the largest open data portals for free lidar data, Open Topography is a widely popular site that hosts data from multiple sources, including files publicly submitted to their community hub. It’s funded by multiple state and government organizations, including NASA, NOAA, and more. Ninety percent of the lidar provided is available in the United States, Canada, Australia, Brazil, Haiti, Mexico, and Puerto Rico. In areas where lidar is unavailable, coarse global DEMs are available for download. This source is also listed in the Online Data tool in the Lidar section.
The United States Interagency Elevation Inventory (USIEI) is a single resource for information about all known, completed, and in-progress broad-area public domain elevation data. It is a joint effort of NOAA and the U.S. Geological Survey, with contributions from FEMA, the National Park Service, the US Army Corps of Engineers, the Natural Resources Conservation Service, and the US Department of Agriculture. The inventory displays high-accuracy topographic and bathymetric data for the US, and it’s intended to be a comprehensive, nationwide listing of known high-accuracy topographic data, including lidar. The inventory is updated semi-annually. Despite the impressiveness of the inventory, it’s often easier to download this data from other federal sources such as the USGS earth explorer.
The EarthExplorer (EE) was developed by the United States Geological Survey (USGS) and provides online search data download of satellite, aircraft, and other remote sensing inventories. Data is available from multiple sources, including the Space Shuttle Radar Topography Mission (STRM), which mapped Earth’s topography at one arc-second (30 meters) for over 80% of the Earth’s surface, and ASTER GDEM-2, which can sometimes be considered a more accurate representation in rugged mountainous terrain than the SRTM elevation model. A study that compared a few of these sources can be found here. Data downloads are not restricted to the US and can be used anywhere. The Explorer site is easy to navigate, and there are many tutorials to help you get started.
Earth Explorer is one of the sources in Global Mapper’s Online Data tool, as mentioned above that will redirect you to the website in your default browser. Loading from the online data tool will automatically pan to your study area as matched to your GM workspace. Download the data to use it in your workspace.
The JAXA Global ALOS portal provides access to ALOS World 3D, a 30-meter resolution digital surface model (DSM) captured by the Japan Aerospace Exploration Agency (JAXA). It’s only recently been made available to the public. This DSM was created from about 3 million images with a 5m resolution captured via the Advanced Land Observing Satellite “DAICHI” (ALOS). It is boasted as the most precise global-scale elevation data currently available. It uses the Advanced Land Observing Satellite “DAICHI” (ALOS) based on stereo mapping from PRISM. Note that downloading the JAXA’s Global ALOS 3D World requires an online registration.
Local governments often provide data on their represented areas. This data is typically collected by private companies and made then available to the public. Often, you can find these on the government’s website through a GIS portal or similar. Sometimes these sources are hosted on servers that can be streamed directly into Global Mapper. To get you started, here is a list of state-wide lidar datasets: https://en.wikipedia.org/wiki/National_Lidar_Dataset_(United_States)
Bathymetric data maps the depths and shapes of underwater terrain, providing valuable information for shipping lane construction, subsurface navigation, geologic history, and more. Accurate bathymetric data is essential because the shape and depth of the ocean floor affect the speed and height of waves, and the coastal land topography primarily determines the inland extent of inundation.
In NOAA hydrographic surveys, the multi-beam and track line bathymetry are provided via the NOAA National Centers for Environmental Information (NCEI). However, access to the bathymetric data can be directly sourced from the NCEI at NOAA Bathymetric Data Viewer. This portal provides lidar but also land cover and imagery. The site boasts visualization tools, predictive tools, and tools that make data easier to find and use. Content comes from many sources, all of which are vetted by NOAA. All of these results can be imported into Global Mapper to integrate with your existing data.
The ETOPO Global Relief Model is a full-coverage, seamless, gridded topographic and bathymetric bare-earth elevation dataset created from regional and global datasets of topography, bathymetry, and shoreline data. The model is designed to support tsunami forecasting, modeling, and warning, as well as ocean circulation modeling and Earth visualization. It’s released globally as a full-global-coverage earth surface elevation file comprised of 288 individual 15×15 degree tiles (latitude/longitude) at 15-arc-second geographic resolution. Also available are additional 62 tiles of “bed” versions that provide bedrock elevations under the surface of the Greenland and Antarctic ice sheets. Access the data download tool here: https://www.ncei.noaa.gov/maps/grid-extract/