Offline areas downloading basemap when set to use device TPK

[JamesTurner2]

I have configured the settings on a map to use a tile package that is already on the device. However, when I create an offline area from the web designer, it still packages the basemap which is defined by the web map. I am trying to shrink offline area sizes by using a sideloaded basemap, but currently, it's not working as expected.

[ChristopherCounsell]

Are you using a custom basemap? I had this the other day and changing to a default basemap in the Web Map fixed the issue.

[JamesTurner2]

I am using a custom basemap. When I switch it to one of the defaults basemaps, my offline area fails to create. This is a known issue in our Enterprise 10.9.1 environment. If we are taking a map offline, we have to use a basemap that is configured 'for export.' If I change the basemap to one that is configured for offline use, it just packages it when I create the offline area. So I'm back to square 1.

[JamesTurner2 · Accepted solution]

After a session with ESRI tech support, the issue was determined to be related to coordinate systems. The sideloaded basemap and feature services in the offline area must be in the same coordinate system. In my case the basemap tile package that I had was in a different coordinate system than the services in the map. Evidently this caveat is noted in the documentation for Enterprise 11.x, but I did not see it for 10.9.1.

I would also note that when you create an offline in Field Maps Designer, it will package the basemap. However, when you download the area on a mobile device it will not download the basemap tile package that was created. The progress counter will appear to download everything, but when the download completes and the area syncs, the overall size is reduced. An example should clarify this.

With the offline area that I have created below, the basemap has also been packaged (VectorTileServe). When you download this area on a mobile device, the progress indicator will show x mb out of 414.6 mb (feature service + basemap). When the download is completed and the area syncs, the file size will be reduced to 325.2 mb (total size - basemap). I found this to be very counterintuitive but ESRI confirmed this is how it should work.