topic Re: Overviews are Blurry for Derived Mosaic Dataset in ArcGIS Image Server Questions

Overviews are Blurry for Derived Mosaic Dataset

KentKauffman1 — Fri, 12 Jan 2018 18:42:44 GMT

I have a worldwide derived mosaic dataset that I am trying to build overviews on for faster service.

I am using 10.4.1, all of the underlying rasters have bilinear jpeg pyramids, and all of the source mosaic datasets follow the same inputs as below.

The derived mosaic dataset has great resolution before I build overviews, but once I build overviews it becomes blurry and useless.

Define Overviews

Extent from Dataset: {blank}

Extent: click Clear

Overview Tile Parameters:

Pixel Size: {blank}

Number Of Levels: {blank}

Number Of Rows: {default}

Number Of Columns: {default}

Overview Sampling Factor: default}

Force Overview Tiles: {unchecked}

Overview Image Parameters:

Resampling Method: BILINEAR

Compression Method: JPEG

Compression Quality 75

Build Overviews

Query Definition: {blank}

Define Missing Overview Tiles: {unchecked}

Generate Overviews: {checked}

Generate Missing Overview Images Only: {checked}

Regenerate Stale Overview Images Only: {checked}

Re: Overviews are Blurry for Derived Mosaic Dataset

PeterBecker — Fri, 12 Jan 2018 19:46:39 GMT

I'd suggest in Define overview you do the following:

Set PS to one of the following: 0.25,0.5,1,2,4,9,19,38,75,150,300,600,1200,2400,4800,9600,19200,38400,77800,153600,

These are scales that are similar but slightly better then those used in most web application. The appropriate value to use will depend the resolution of the source data and existence of pyramids and size of the source data images. If creating from the source data and assuming the data has pyramids you can use value closest to width of source data (m) / 1000 would be an estimate. If you have already created source mosaic datasets that have their own overviews then set to width of smallest source mosaic dataset extent/1000.

Set OverviewSampling factor to 2. (I nearly always recommend this be set to 2 not the default 3)

Set JPEG quality to 85.

Give this a try and see if it helps.

Re: Overviews are Blurry for Derived Mosaic Dataset

OlgaKoblet — Wed, 21 Apr 2021 11:42:43 GMT

Could you please go into a bit more detail why you reccomend the Overview Sampling of 2?