server cache still using source files

[EricGardecki]

I have a few imagery tile caches created based on imagery in either MrSid or Grid format in ArcGIS Server.  I'm trying to clear out some hd space and wanted to remove the copy of the imagery that is on that server, or at least move it.  However, despite the cache being created, and I assume being all that is used to display the imagery, Server will not allow me to remove the imagery files that were used to create the cache.  If I stop the server service and remove the files, no imagery appears anymore in my applications.

1.  Why would a cache need the original imagery data when working with a cache?  Is there some way to change this?

2.  Where is the reference to the original imagery located so I can change it?  I would like to move the data to another drive but not have to recreate the caches since it cripples the server during that process.

Thanks!

[RebeccaStrauch__GISP]

My guess is yes, that could be the reason for the lock since as dynamic, it will be trying to access the service and original data sources.

So, it sounds like it is more of a Flex web app issue, and not an issues with ArcGIS Server.  I would mark Robert's answer as correct, and maybe try Moving Content​ to ArcGIS Viewer for Flex​   ...but then again, I just tagged it so the thread will be discoverable over there too. 

[EricGardecki]

I have to unmark this as the answer.  Although I had this working at one point, it isn't any longer and I can't reproduce it.

So I have no idea why the cache is holding on to the source imagery files but it is and I can't seem to do anything about it.

I'll just find a way to work around it.

[MarkChilcott]

Hi Eric,

You may want to consider building a skeleton Map Service.

In this you have a layer in the map document that is just the extent of the area, and the map service relies just on the cache.  Therefore it only ever returns the cache tiles.  We use this technique all the time - very fast response as only the tiles from the cache are ever returned, and once in the client browser do not need to be sourced again.

I can post rough outline of how to build skeleton map service if interested.

caveat : Map services using skeleton map service will return the feature if WMS request.  Therefore in this case would require an image service.  More on that later if required.

Cheers,

Mark

[EricGardecki]

Sounds like a good idea but unless I can bypass the zooming to LODs with your method I don't think it'll work for me at this time.  If it can be bypassed then I'm all ears!   Thanks!

[RobertScheitlin__GISP]

Eric,

   My ParcelViewer both Flex Version and WAB versions use cached based maps and thus are confined to LODs but I have added several extra LODs that allow of tighter zooming to small parcels. So that is always an option. I think you will find the added speed of a cached map is worth the switch.

[EricGardecki]

Do you mind sharing what LODs work best for you?

Having one for every scale we tend to need just seemed like a bad idea due to the time it takes to build the cache and the huge amount of storage needed.  The latter of which is what led me to this question to begin with....but will be remedied in the near future I hope.

[RobertScheitlin__GISP]

Eric,

   I use the esri basemap LODs and then add these scale "2256.994353", "1128.497176", "564.2485881" and this has served me just fine for parcel mapping. Several of the base maps now go down to "70.5310735" now as of last year.

Here is my Flex Viewer lods portion of the config.xml

<lods>

            <lod resolution="0.14929107085026672" scale="564.2485881"/>

            <lod resolution="0.29858214164761665" scale="1128.497176"/>

            <lod resolution="0.5971642835598172" scale="2256.994353"/>

            <lod resolution="1.1943285668550503" scale="4513.988705"/>

            <lod resolution="2.388657133974685" scale="9027.977411"/>

            <lod resolution="4.77731426794937" scale="18055.954822"/>

            <lod resolution="9.554628535634155" scale="36111.909643"/>

            <lod resolution="19.10925707126831" scale="72223.819286"/>

            <lod resolution="38.21851414253662" scale="144447.638572"/>

            <lod resolution="76.43702828507324" scale="288895.277144"/>

        </lods>

[EricGardecki]

I should probably know this already but it is escaping me and I can't find the answer in a search so....

why are your/esri LODs such odd (not rounded) numbers?

We naturally want our maps printed to a useful scale so I would want mine to be 240, 360, 480 etc.

[RobertScheitlin__GISP]

Eric those are the esri AGOL scales for using esri Web Mercator Basemaps. I have a version of Flex Viewer that uses strictly my own State Plane data and for that one I have normal scale as you mention. But if you want to use esri base maps you have to cache your data at the same scale as they use.

[EricGardecki]

I figured as much but why did they choose what they did?  Off topic I know but I'm curious.