Cache Question - Data Storage

[JustinHunter]

Hey all,

Quick question - I have a map of the entire country (Canada) that have 16 zoom levels all the way down to 4000. Would it be better to store all my data in my SQL Server database or leave it as a local gdb? I already have a 'query map' of sorts where almost all the layers of my display map use stored in my SQL Server, but I thought it'd be faster for it to read from my local machine's SSD for the caching portion.

Any suggestions on the fastest way for reading data would be would be great.

Thanks

[AnthonyGiles]

Justin,

It all depends on the file type and compression used on the imagery. Sometimes importing the imagery into a SQL database can ballon the data (for instance we use a source of imagery that is in MrSID format and this can expand from around 2GB a tile to 30GB in the database).

What I have found that works well is to create a unmanged raster catalogue in a file gdb and leave the imagery in its raw format and build pyramid layers on it.

The amount of time it takes to display the imagery in ArcMap will have a knock on effect to how long your caching will take on the server. You can speed this time up by increasing the amoiunt of instances on the sever whilst creating your cache. Once you have built your cache for your web app the user gets a fast service from the pre cached tiles. If space is at a premium you can actually remove the original imagery from your file system as it is no longer needed by your service (that is if you have totally cached your whole area and not relying on cache on demand).

Hope this helps a little

Regards

Anthony