Dear ESRI Support and GIS Users.
Can anyone help me with how best to get good quality overviews? I know this is a little subjective…my case:
I create the Raster Mosaic Dataset in a fGDB and add the following tifs to it.
200 tifs, each tif 20MB in size, all tifs fit together like squares on a chessboard
Number of bands: 3
Cell size 1.25 x 1.25
Source Type: Thematic
Pixel Type: unsigned integer
Pixel Depth: 8 bit
NoData Value 256,256,256
Overview Tile Parameters
Pixel size: 1.25
Number of Levels: 12
Overview Sampling Factor: 2
Overview Image Parameters
Resampling Method: BILINEAR
Calculate item visibility – take Default settings.
Scale 1:8000 –= viewing the original tif, not the overviews – quality good
Scale 1:8000 – 20000 = viewing the overviews – quality poor. I know this is a little subjective – but the image is quite
blurred, hard to read labels…
 I have tried changing the Number of Levels and Overview Sampling Factor
 I have tried changing the Resampling Method and Compression
Nothing seems to help.
[A] Is the problem in the original tifs? For example the source Type or Compression used?
[B] Is the problem in how I define the Overview Generation?
Feedback welcome and appreciated.