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India presents among the world's most topographically complex geomorphologies, with land elevations ranging from -2 m to +8586 m and terrain gradients sometimes exceeding 45°. Here we present an evaluation of four freely available digital surface models (DSMs) on a model-to-model basis, as well as a validation using independent ground-truth data from levelled benchmarks in India. The DSMs tested comprise SRTM1", SRTM3", ASTER1" and Cartodem1" [an India-only model]. Along with these four DSMs, the MERIT3" digital elevation model (DEM) is also tested with the ground-truth data. Our results for India indicate some mismatch of these DEMs/DSMs from their claimed accuracies/precisions. All DSMs/DEMs (except for ASTER) have >90% of pixels satisfying ±16 m at the one-sigma level, but only in the low-lying (<500 m) parts of India, i.e., the Gangetic plains and the Thar desert.

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