Unlocking Earth’s Topography: Exploring Public Sources of Geospatial Data

Unlocking Earth’s Topography: Digging into Public Geospatial Data

Ever wonder how scientists, city planners, and even disaster relief teams get a handle on the lay of the land? Well, a huge amount of geospatial data is out there, free for the taking! It’s like having the keys to a detailed map of the planet, and it opens up some seriously cool possibilities for analysis and visualization. Let’s dive into some of the best places to find this data and how you can put it to work.

DEMs: Your Topographic Foundation

Think of Digital Elevation Models (DEMs) as the bare bones of the Earth’s surface, a digital representation that strips away the trees and buildings to show you the ground underneath. You can snag DEMs from a bunch of different spots, but keep in mind they’re not all created equal. Resolution, coverage, accuracy – it all varies.

• USGS Earth Explorer: This is like the grand central station for elevation data. The USGS Earth Explorer is where you can find the Shuttle Radar Topography Mission (SRTM) data. This mission mapped most of the world – over 80%! – at a pretty decent resolution of 30 meters. You’ll also find the ASTER Global Digital Elevation Model (GDEM) here. It’s got a global resolution of 90 meters, but bumps up to 30 meters in the US. Heads up: you’ll need to register to download anything.
• The National Map (TNM): Want to zoom in on the US? The National Map, or TNM, is your go-to. Led by the USGS, it’s got all sorts of topographic info, including the raw Lidar data and the DEMs that come from it. The best part? Downloads and map services are free, and you don’t even need an account.
• Copernicus DEM: The European Union’s Copernicus Programme offers the Copernicus DEM, and it’s a real game-changer. You’ve got three versions to choose from: EEA-10, GLO-30, and GLO-90. GLO-30 gives you global coverage at 30 meters, while GLO-90 is at 90 meters. This data comes from the TanDEM-X mission between 2011 and 2015, becoming available in 2019.
• JAXA’s Global ALOS 3D World: Japan’s space agency, JAXA, has the ALOS World 3D, a 30-meter resolution digital surface model (DSM). It’s built using stereo mapping from the ALOS “DAICHI” satellite. You’ll need to register to get your hands on this data.
• Open Topography: OpenTopography is like a one-stop-shop for open-source topographical datasets and tools. It pulls together data from all sorts of places, including government agencies and universities. They’ve got some seriously high-resolution datasets. Word to the wise: while it used to be completely free, you might need a subscription now to unlock everything on their LiDAR platform.

LiDAR Data: Seeing the Earth in High-Def

LiDAR is where things get really interesting. This tech uses lasers to create super-detailed 3D maps of the landscape. If you need pinpoint accuracy, LiDAR is your best friend.

• USGS 3DEP LidarExplorer: The USGS 3D Elevation Program (3DEP) is working to collect LiDAR data for the whole US. The 3DEP LidarExplorer lets you grab point cloud data and DEMs derived from LiDAR.
• NOAA Digital Coast: NOAA’s Digital Coast program is all about LiDAR data for coastal areas. Their web map lets you find, play around with, and download free LiDAR data for these regions.
• OpenTopography: Remember OpenTopography? It’s still a great source for LiDAR data, even if you need a subscription for full access.
• LidarBC: If you’re interested in British Columbia, the government there offers open access to LiDAR data and related datasets collected within the province.

Beyond DEMs and LiDAR: More Geospatial Goodies

DEMs and LiDAR are fantastic, but there’s even more out there!

• NASA Earthdata: NASA Earthdata is a treasure trove of remote sensing data from space missions. Think MODIS, SMAP, and GPM.
• Copernicus Data Space Ecosystem: This ecosystem gives you access to Earth observation data from the Copernicus Sentinel satellites.
• Natural Earth Data: Natural Earth Data offers key cultural and physical vector GIS datasets on a global scale. The best part? They’re in the public domain, so you can use, tweak, and share them as you please.
• FAO GeoNetwork: The Food and Agriculture Organization (FAO) GeoNetwork is a portal for free GIS data focused on global sustainable development. It’s got data on agriculture, food security, and fisheries.
• WorldPop: WorldPop focuses on high-resolution geospatial data on population distributions, demographics, and dynamics.

Putting the Data to Work

Okay, you’ve got the data. Now what? Here are a few tools to help you make sense of it all:

• GIS Software: You’ll need GIS software like QGIS (free and open-source) or Esri’s ArcGIS to create, edit, analyze, and visualize spatial data.
• Remote Sensing Software: Software like Global Mapper lets you stream data directly into a workspace and handles all sorts of elevation data formats.
• Open Topo Data: Open Topo Data is an elevation API that you can host yourself or use via a free public API. It’s got a point query endpoint for grabbing elevation data and plays nicely with the Google Maps Elevation API.

Wrapping Up

The explosion of public geospatial data has completely changed how we study and understand the Earth. By tapping into these resources, we can unlock incredible insights into our planet’s surface. This leads to smarter decisions and a more sustainable future. So, get out there and start exploring!