Can custom basemaps be enabled for offline use

[LindsayRaabe_FPCWA]

In short, what I want to know is can custom basemaps be enabled for offline use? I've followed the guide in this blog post to create and share Custom Basemaps with my org, but I don't seem to be able to use them in a webmap and have that map enabled for offline use in Field Maps. 

Extra info: my custom basemaps either use the ESRI Terrain or ESRI Imagery basemaps with a Custom Vector Tile Package overlaid within the basemap group of the webmap share to the Custom Basemap Gallery group. The Vector Tile Package is enabled for offline use, as are the webmaps. 

[ATFerguson]

I have the same question. Were you ever able to find a solution? 

[LindsayRaabe_FPCWA]

Been a while since experimenting with this!

We work around this by having our Vector Tile Package sideloaded to mobile devices and the webmap set to use the local vtpk when going offline in FIeld Maps Designer.

To be honest, I'd forgotten that I couldn't get this working (and just thought it did) but doing some quick tests now before replying shows that when trying to take a map offline with our custom basemap (ESRI Imagery + custom VTPK in the maps basemap group), it errors out on Field Maps. When changed to just the default Imagery basemap, it worked fine. So apparently no, it still doesn't work. 

[ATFerguson]

Thanks for getting back and running those tests. I'll follow up here if I'm able to find a workaround.

[LindsayRaabe_FPCWA]

Please do!

[kterry1983]

Hi Lindsay,

Would you mind pointing me to more info on sideloading a Vector Tile Package? I would like to use a hillshade in offline areas.

[LindsayRaabe_FPCWA]

Fields Maps:

Configure the mobile app—ArcGIS Field Maps | Documentation

and for Survey123:

How To: Sideload Tile Packages to the ArcGIS Survey123 Field App

[GregCarlino2]

This is a great post! I have the same issue, as well.

I'd like to be able to use Field Maps in a State Plane projection rather than the standard Web Mercator.  I have also tried sideloading my own State Plane-projected imagery onto my tablet.  However, Field Maps Designer still won't let me enable a web map that uses both a custom basemap (with an alternate projection) AND that is offline-configured.  It just keeps saying that the basemap 'layer type is not supported', no matter how I reconfigure it.  Furthermore, the available offline ESRI tile layers are extremely limited in terms of projections and don't cover specific states' projections.

I'm hoping somebody eventually finds a way for this to work and posts about it here.

[ATFerguson]

This doesn't answer your question for a few reasons (I was never able to get .vtpkx basemaps to work and I've never used field maps), but, for what it's worth, the Basemap Gallery Widget in Web Appbuilder comes with an "esri_tileinfo.json" file that defines the tile scales for Web Mercator. In order to host non-web mercator basemaps, I had to overwrite the default tiling info with the tiling info for the coordinate system being used by my basemaps. I imagine there is some config somewhere in Field Maps that defines the same.