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The impact of high resolution DSM errors on View Shed calculation. An Van Delm CE 697V. methodology. 4 random rasters, height 0-1feet Each x1, x2, x5, x10, x20 Added by reference DSM (Indiana State) Creation of 2 view points (street – square) 2 x 20 viewsheds. A. A’. C. D. 2.
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The impact of high resolution DSM errors on View Shed calculation An Van Delm CE 697V
methodology • 4 random rasters, height 0-1feet • Each x1, x2, x5, x10, x20 • Added by reference DSM (Indiana State) • Creation of 2 view points (street – square) • 2 x 20 viewsheds
A A’ C D 2 A A’ B B’ D D’ 1 C’ C C’ D’ B B’
View shed surface (cells) / max error (ft) Point 1 Point 2
View Sheds point 1, + random raster error 1, 2, 3, 4 x1 reference 4. 1. 2. 3.
Profiles point 1, reference DSM N-S E-W Error horizontal, decreases view
View Sheds point 2, + random raster error 1, 2, 3, 4 x1 reference 4. 1. 2. 3.
View shed surface (cells) / max error (ft) Point 1 Point 2
View Sheds point 1, + random raster error 2 x1; x2 ; x5 reference x1 x2 x5
conclusion • Small errors are important close by, especially for open areas • Street views are more sensitive for all kinds of errors • Take notice of the horizontal errors! • Larger errors give similar effect for open or closed areas