30X30 DEM

[YaredMichael]

Hello,,,

I have just downloaded a 30x30m DEM from  ASTER GDEM. However, after I mosaic it and open in in Arcmap, I found it to be actually 0.00027777x0.00027777m resolution and could not get a realstic feature (vertical lines) when I export and view it in HEC-RAS.Your usual and kind helps please.

Yared.

[KishorGhatage]

Use mosaic to new raster tool and Set output cell size to 30 while mosaicing the DEM's.

[DanPatterson_Retired]

your coordinates appear to be in decimal degrees.  This can be confirmed by looking at the layer's properties.  If they appear to be in the realm of decimal degree coordinates, then you need to project the raster to your desired projection (ie UTM etc etc) using the Project Raster tool in ArcToolbox