A Digital Elevation Model or a DEM is a 3 dimensional representation of the elevation of a terrain, usually in raster file format. Each cell in the raster represents the elevation of a specific area in the terrain. DEM can be used for various purposes such as Hydrological modelling, Terrain visualization and analysis, Engineering and Infrastructure Designs etc. Some of the most commonly used freely available DEMs are ASTER GDEM AND SRTM DEM. These data sets can be downloaded from official websites and a number of other websites. But one of the disadvantage of these websites are the users need to download a full tile of DEM, even if they need data for a relatively small area.
So today we are going to learn a way which allows the user to download data of their own area of interest using the Google Earth Engine Explorer. So what is earth engine explorer? The Google Earth Engine Explorer is a simple web application for exploring the huge amount of freely available geographic data stored in the Google Earth Engine Catalogue. The user can search for various types of earth observation datasets such as digital elevation models, weather data, climate data etc. The Google Earth Engine Explorer also allows the user to import, run simple analysis and save and export the result.
The steps to download SRTM DEM Using Google Earth Engine Explorer are as following
- Sign up to Google Earth Engine Explorer using your Google account here
- Zoom in to your area of interest by using the search bar or scrolling your mouse wheel
- Search for “NASA SRTM Digital Elevation 30m” in the search bar
- Your search result will be added to the Table of Content on the left side of the screen. Also, a pop-up will be appeared on the screen. Here you can change options to get a better visualization of your area of interest
- Change the default visualization parameters using the palette option if required
- Click on download layer option
- Click on View port button to choose either polygon or rectangle to choose your area of interest
- Choose an appropriate file format. Also, if necessary, you can change the projection. Change the resolution to 30 m
- Click on download button to download your data
- Unzip your data and open it in your favourite GIS software for further analysis