Set the Observer Location by positioning the Cross-hairs over the required point and tapping the Done Button to return to the Curve Calculation.
Tap the Cancel Button to return without updating the Observer Location. You can explore the Map using the following gestures:
Scroll the Map.
Double tap to zoom in to that point.
Spread to zoom in.
Pinch to zoom out.
If required, you can rotate the Map to reflect the direction you are heading. Tap the Compass that appears in the upper right corner of the Map to re-orientate with North to the top.