Recipe to make a native Patterson map

Ingredients:

1. Convert your fin file to an empty phase file using xprepfin. In xprepfin set Use Data: to "Avg F1 and F2" to average the Bijvoet pairs and set Output Format: to "Fake .phs".

2. Load the empty phase file into xfft. Set Map Type: to "Fo*Fo (Patterson)" and push calculate.

3. Load the resulting map into xcontur and enjoy.