Within the Explorer app, there are a number of map layers available.
These map layers come from a number of sources.
Some of the layers are created and maintained by Hema.
Others are provided by 3rd parties, such as HERE maps, or various Australian state government mapping bodies.
Currently, the map layers within the app are built using a technology called raster maps.
Raster maps are essentially an image of the map area, which contain information which allows the app to know the area that the map covers.
Because the app knows where you are located, and knows the bounds of the currently active map layer, it can plot your position on the map.
Offline versus online map layers
Hema Explorer provides access to both offline and online maps.
Offline maps are where the map source content is stored locally on the device. It means that the maps can be viewed even if there is no network connection present.
The offline content must still be downloaded to the device so the app can access it while offline.
Online maps are map sources where the content is stored on a server, and must be streamed (dynamically downloaded) to the device for the app to display it. For this to happen, an internet connection must be available via which you can access the server.
Generally any app which uses online maps provides a mechanism by which either entire map sources, or segments / sections of a given map source can be selected and downloaded to the local storage, so that the online map sources becomes available for offline use.
Often, complete raster map sources are NOT available offline due to the large size of the data, particularly at higher zoom levels.
The range of map layers available in Explorer can be managed from the More Maps panel within the app.
Explorer can download the Hema Explorer map layer for the entire Australian continent (as states / regions). The downloaded files contain this map layer to a maximum zoom level of 12 (which equates to a scale of around 1:150,000).
As mentioned previously, raster map files can be large, depending on the scale, and while the Hema Explorer map source actually provides a maximum zoom level of 16 (accessible via the Explorer Pro subscription - around 1:9,000 scale) it is not possible for the files to be fully downloaded at this zoom level due to their extremely large size.
What this means, is that, if you venture out of range of internet coverage, you need to download a selected area for use while offline BEFORE you leave home.
See the User Guides for details.
For the iOS version: