Can you install Hema maps outside of the Google Play or Itunes store?

No, you cannot do this.

Your device needs to be able to access the Google Play Store (for Android devices), or the Apple iTunes Store (for iOS devices) to be able to buy, download and install the hema apps.

If your device has no way of connecting to the internet, and therefore is unable to access the respective store, then there is no other way of loading the apps.

ie. you cannot download it to a Windows PC, and then copy it to an SD card, USB stick etc. to install.