Combine basemaps

[RebeccaWatson]

I have a cached imagery layer as a basemap in my flex app which took quite a few days to set up. We now have another small area that we want to add onto the imagery which is at a finer resolution. Instead of starting from scratch and having to re-sample and re-cache with the new area in, is it possible for me to just do the new bit separately and have it show as though it is part of the original basemap e.g. essentially have two basemaps, but the user only sees one?

I am using 3.3 and I do have access to the code through Flash Builder, but I've only just starting to look at flex programming, so I'm a beginner really. I don't have the Image Server Extension.

Does anyone have any ideas on how to get my additional imagery into the basemap with the least processing time?
Thanks

[RobertScheitlin__GISP]

Rebecca,

   Once you have created the cached map service for the new imagery then all you need to do is add it to the main config.xml and add min and max scale attributes to it and your original basemap. This will work seamlessly to your users if both have the same label and are both set to visible in the main config.xml:

example:

            <layer label="Main Basemap" type="tiled" visible="true" alpha="1" icon="assets/images/basemap_imagery.jpg"
                   url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Street_Map/MapServer" 
                   maxscale="9027.977411" minscale="591657527.591555"/>
            <layer label="Main Basemap"  type="tiled" visible="true" alpha="1" icon="assets/images/basemap_imagery.jpg"
                   url="http://server.arcgisonline.com/ArcGIS/rest/services/World_Imagery/MapServer"
                   maxscale="1128.497176" minscale="9027.97740"/>

The scales have to be exact from the scale of your cache (you can get the exact numbers by going to the rest service directory for that map service).

[RebeccaWatson]

Hi Robert,
Thanks for your reply. My two areas are next to each other rather than being two different resolutions of the same area. I have two options in my basemap switcher - Hi-res Imagery and plain white background. When the user clicks Hi-res Imagery I want them to see the original area imagery and the new area imagery at the same time and at all scales. I could just put the new area in separately, but I want the imagery for the two areas to turn on/off together as though it is one image, rather than the user having to select area 1 or area 2 in the basemap switcher.
Thanks,
Rebecca

[RobertScheitlin__GISP · Accepted solution]

Rebecca,

   So if you want both to be visible than you just name them the same. But if they are cached at different scales then you have a problem. If they are the same scales but one has additional Levels of Display then all you have to do is manually specify the maps LODs. Look at the documentation for examples of using the maps lods tag:

http://resources.arcgis.com/en/help/flex-viewer/concepts/index.html#/Map_content/01m30000005p000000/

[RebeccaWatson]

That's just what I wanted, and much simpler than I was imagining it would be! Thank you very much Robert.