The software used to create offline map tiles is MapBox TileMill
Download Example Tiles ** If downloading and trying with this file you can start and Step 5
Add the layers to the TileMill project, and style the map how you wish.
Once the you are happy with your map and you are ready to export the map select the Export button in the top right corner of the application
Specify the extent and zoom level to tile in the right side panned and select the export button
Once the tiles have been created you can select the View exports button and click the save button. This will then prompt you with the location you your tiles you have created.
Next navigate to the the "geoodk" folder on the device
Then navigate to the "OfflineLayers" Folder with in geoodk folder. (geoodk/OfflineLayers)
Create a New Folder, and name the folder something related to the layer.
Inside the folder you just created pasted the .mbtiles file there.
Open the GeoODK Collect App and select "Map Data"
You will see a layers icon on the right side, select the button
From here you will see a list of layers that are on the devide. Select the on you want to be displayed on the map. Currently there is only functionaly to show one layer at a time. This is for performace reasons.
Once the layer has been selected navigate to the layer. Note: depending on your current zoom level and the zoom level that your layers is tiled you may have to zoom in or out.
From here you can zoom in and out to view the layer. There is the same option when collection a geoshape in the form, you can also display your offline layers