Mosaic to New Raster Causes a Shift - Please help!

Question

Hello all,

I am working on a floodplain mapping project and have created depth grid rasters for each stream within the 100 year floodplain of the desired area.  I have used the Mosaic to New Raster tool as well as Workspace to New Mosaic.  Both produce a seamless depth grid for the entire area, but the new raster dataset seems to shift to the southeast by 60-80 ft.  Have any of you experienced shifting when using either of these tools?  If so, what would be the most efficient way of fixing this problem?  Any help would be greatly appreciated.  Thanks!

curtvprice · Answer

(I) have created depth grid rasters for each stream within the 100 year floodplain of the desired area.  I have used the Mosaic to New Raster tool as well as Workspace to New Mosaic.  Both produce a seamless depth grid for the entire area, but the new raster dataset seems to shift to the southeast by 60-80 ft.

The time to set the snap raster environment is before you create each of the input rasters so the grid cells will all neatly  line up with each other. If the grid cells in the input rasters do not "line up," at least one of the input rasters to the mosaic operation will have to be resampled.

PetronilaMandeno · Answer

I guess another thing to check is if the projection is correct (or the same) for both raster sets you are creating the new raster from?

Anonymous User · Answer

That is strange indeed.  You could try redoing the mosiac and "snapping" the raster in the environment settings.  I haven't done this in a long time, but if I remember correctly this should snap the mosiacked raster to the lower left corner of the input extent.

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#//001w0000000m000000

Hope this helps

Caleb