Trying to iteratively mosaic rasters into single raster; fatal errors

Anonymous User — Sat, 11 Dec 2021 18:54:36 GMT

Original User: ddombroski

Hello, fairly new to python and arcpy scripting here. I have a script where I'm iteratively (within a loop) creating raster tiles from numpy arrays. As I create them, I would like to build a single larger raster that will contain all the tiles after the loop has finished (presumably a mosaic). The arcpy.Mosaic_management function is failing with errors that I cannot figure out.

Here is the bulk portion of the code:

# Create empty raster for tiles to go into
ghsi_rast = arcpy.CreateRasterDataset_management(rast_dir,ghsi_out,"5","32_BIT_FLOAT","","1","","","","","")
#ghsi_rast = arcpy.CreateRasterDataset_management(rast_dir,ghsi_out)

for r in range(0,nrows,tile_size[0]):
    row_end = min([nrows,r+tile_size[0]-1])
    row_step = row_end-r+1
    for c in range(0,ncols,tile_size[1]):
        # determine indices for the tile to be processed
        col_end = min([ncols,c+tile_size[1]-1])
        col_step = col_end-c+1
        # convert each tile from the Raster to a numpy arry for processing
        dep_subarray = arcpy.RasterToNumPyArray(dep_rast,arcpy.Point(r,c),row_step,col_step,nodata_to_value=noDataValue)
        vel_subarray = arcpy.RasterToNumPyArray(vel_rast,arcpy.Point(r,c),row_step,col_step,nodata_to_value=noDataValue)
        # create a mask of the nodata values (to be used before converting back to raster)
        mask = ma.masked_where(vel_subarray==noDataValue,vel_subarray)
        mask = mask.mask        
        # interpolate HSI values to depth and velocity arrays
        vhsi_subarray = np.interp(vel_subarray,vel,vel_hsi)
        dhsi_subarray = np.interp(dep_subarray,dep,dep_hsi)
        # apply mask to VHSI & DHSI arrays
        vhsi_subarray = ma.array(vhsi_subarray,mask=mask)
        dhsi_subarray = ma.array(dhsi_subarray,mask=mask)
        # calculate global HSI
        ghsi_subarray = np.sqrt(vhsi_subarray * dhsi_subarray)
        # convert global HSI back to raster and add tile to larger raster
        ghsi_subrast = arcpy.NumPyArrayToRaster(ghsi_subarray,arcpy.Point(r,c),cell_size)
        arcpy.Mosaic_management(ghsi_subrast,ghsi_rast,"","","",noDataValue,"","","")

Here's the error I seem to be getting:

arcpy.Mosaic_management(ghsi_subrast,ghsi_rast,"","","",noDataValue,"","","")
  File "C:\Program Files\ArcGIS\Desktop10.0\arcpy\arcpy\management.py", line 7168, in Mosaic
    raise e
ExecuteError: ERROR 999999: Error executing function.
Failed to rename raster dataset
Failed to execute (Mosaic).

Thoughts on where I've gone wrong? Thanks

Re: Trying to iteratively mosaic rasters into single raster; fatal errors

Anonymous User — Thu, 09 Aug 2012 17:37:56 GMT

Original User: temge

Nothing in the code really stands out as big no-no. I would start filling in some of the parameters in the mosaic function explicitly. Even though the UI might consider them optional you might still have to fill in some values.

- Thomas

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Trying to iteratively mosaic rasters into single raster; fatal errors

Re: Trying to iteratively mosaic rasters into single raster; fatal errors