Uncertainties in Digital Elevation Models from Global Advanced Land Observing Satellite (ALOS) digital topography data in the Indian subcontinent

The study of the Earth's topographic surface using digital topography is an important component of many problems in the Earth Sciences. The 30-m Shuttle Radar Topography Mission (SRTM) and the Advanced Land Observing Satellite (ALOS) global digital topography datasets have been the most recently available global digital topography datasets. Most users directly download the data/DEMs in their native form assuming a vertical error close to their mission goals. We demonstrate, through the use of 221 dual-frequency static Global Positioning System (GPS) independent ground control points, that the datasets typically have outliers and voids that increase the error by an order of magnitude. Filtering the voids, outliers, and correcting systematic errors significantly improved the vertical accuracy of the datasets. We concluded from our study that the ALOS data generated the most accurate DEM in the Indian subcontinent. This finding needs to be tested and confirmed worldwide for generating the best DEMs.

Automated summary

The study of Earth's topographic surface using digital topography is crucial in Earth Sciences. The most recently available global digital topography datasets, such as the SRTM and ALOS datasets, often contain outliers and voids that significantly affect the vertical accuracy. Filtering and correcting these errors can improve the accuracy of the datasets. The study concludes that ALOS data generated the most accurate DEM in the Indian subcontinent, but further testing worldwide is needed for generating the best DEMs.