Image Caching with ArcGIS Server

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Image Caching with ArcGIS Server

• Michael Kolonay
• GIS Systems Admin/Application Developer

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• What is a Map Service Cache in ArcGIS Server?
• Pre-rendered images based on a map service.
• Created at predefined scale levels.

Source ESRI
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• Why Cache?
• Speed.
• Cartographic Quality.

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• Why Cache?
• Speed.
• Using an image cache significantly improves map
  service performance.

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• Why Cache?
• Speed.
• Using an image cache significantly improves map
  service performance.

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• Why Cache?
• Cartographic Quality.
• Using an image cache allows more complex
  symbology

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• What are the requirements?
• ArcGIS Server
• Data Storage
• CPU time

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• What are the requirements?
• Data Storage
• How much space will you need to Cache your base
  maps?
• Generally speaking when we cached from a tif
  raster catalog the cache was 16-37 of the total
  catalog size.
• When caching from SDE the cache was 284 of the
  disc space required for the feature class.

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• What are the requirements?
• CPU Time
• How time will it take to create a cache?
• Depends on where/how you have your data stored
• Depends on the type of system you have

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• Some More Details Various Caches

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• Some More Details Tiff Tiles

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• Some More Details- Tiff Cache Size Growth

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• Some More Details- Tiff Cache Size by Scale Level

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• Some More Details- 2002 6in 1ft Cache Size by
  Scale Level

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• Some More Details- 2002 6in 1ft Cache Size by
  Scale Level

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• Some Standards Used
• Scale Levels
• Tile sizes
• 512 X 512
• File Formats
• JPEG for aerial imagery.
• PNG for road basemaps.

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• Walkthrough of Caching
• We first tried caching the entire state using the
  tools in ArcCatalog.

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• Brief Walkthrough of Caching
• We first tried caching the entire state using the
  tools in ArcCatalog.
• This did not work well for us.
• Too many empty tiles were created.
• Difficult to recover from when process failed.
• So instead we used a python script.
• Update Map Server Cache by FeatureClass by
  Jeremy Bartley.

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• Example of FeatureClass that we used.

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• Some Examples
• http//spatialserver.yesvirginia.org/2002_imagery_
  cache
• http//spatialserver.yesvirginia.org/2002_imagery_
  NoCache/

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• What else are we using ArcGIS Server for?
• Internal Consumption of Basemap Cache.
• Replacing raster storage in SDE with Cache.
• External Consumption
• Soap Services (Cached and non-cached.)
• Web Map Applications
• Database Replication
• Replicating sites and buildings data with
  Virginia localities.

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• Sources
• Authoring and Publishing Optimized Map Services
• Building and Using ArcGIS Server Map Caches -Best
  Practices. (From Developer Summit 2007)
• ArcGIS Server Best Practices and Guidelines.
  (NEARC 2007 ESRI Technical Session)
• Web Application Stress Test Methodology
• Update Map Server Cache by Feature Class