Validation of GDEM and SRTM Accuracy Based on NIDEM Model
Author(s):
Abstract:
The main goal of the study is evaluation of accuracy and precision of both versions of global digital elevation model (GDEM1, 2009; GDEM2, 20119) with 30m ground resolution and comparison of it with SRTM model (with 90 m resolution) and DEM produced by National Cartographic Center of Iran (or NIDEM with 10 m resolution). In order to achieve the goals mentioned, three different strips with various geomorphic characteristics have been selected and studied. After inland waters omission, all three models are resampled to models with one arc seconds resolution. In addition, differential layers of various DEM have been calculated and the distribution of errors in each strip has been investigated. Various types of errors and their spatial distributions in models are distinguished using scatter diagrams and scatter clouds. For visualizing of DEM's error, Hill shade models and topographic profile along selected errors has been prepared for all models. The results of the study showed that GDEM1 leads to significant error's respect to SRTM, which is related to the method of production. The results also showed that various types of anomalies such as "Step-anomalies", "Pit-anomalies", "Bump-anomalies" and "Pit-in-Bump anomalies" are clearly related to the stack number boundaries. The error ranges of the mentioned anomalies are from ten meters to more than 300. The mean of error in GDEM1 is 4.8 m with standard deviations equal to 13.8 m which its range in 95% confidence is between -22.3 to 31.9 m. Analysis of GDEM2 showed a significant improvement in quality of model respect to previous version. The mean of error in GDEM2 is less than of 3 m with standard deviations equal to 9.1 m which its range in 95% confidence is between -20.8 to 14.8 m. In comparison, the mean of error in SRTM is 2.0 m with standard deviations equal to 8.7 m which its range in 95% confidence is between -15.1 to 19.1 m. Moreover, the study showed GDEM1 was not as sharp as a standard 30 m resolution DEM and appeared to contain fewer spatial details. On the other hand, most of the errors in GDEM2 have been omitted and revealed an acceptable accuracy
Language:
Persian
Published:
Iranian Journal of Remote Sencing & GIS, Volume:4 Issue: 3, 2012
Page:
81
https://www.magiran.com/p1173529
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