There are 5 different types (MKMapType), MKMapView can display.

.standard

Displays a street map that shows the position of all roads and some road names.

Swift 2

mapView.mapType = .Standard

Swift 3

mapView.mapType = .standard

Objective-C

_mapView.mapType = MKMapTypeStandard;

.satellite

Displays satellite imagery of the area.

Swift 2

mapView.mapType = .Satellite

Swift 3

mapView.mapType = .satellite

Objective-C

_mapView.mapType = MKMapTypeSatellite;

.satelliteFlyover

Displays a satellite image of the area with flyover data where available.

Swift 2

mapView.mapType = .SatelliteFlyover

Swift 3

mapView.mapType = .satelliteFlyover

Objective-C

_mapView.mapType = MKMapTypeSatelliteFlyover;

.hybrid

Displays a satellite image of the area with road and road name information layered on top.

Swift 2

mapView.mapType = .Hybrid

Swift 3

mapView.mapType = .hybrid

Objective-C

_mapView.mapType = MKMapTypeHybrid;

.hybridFlyover

Displays a hybrid satellite image with flyover data where available.

Swift 2

mapView.mapType = .HybridFlyover

Swift 3

mapView.mapType = .hybridFlyover

Objective-C

_mapView.mapType = MKMapTypeHybridFlyover;