PV land area estimate currently based on module surface area:

Land Area Estimate = Total Module Area * Land Area Multiplier + Additional Land Area

This requires that the user adjust the land area multiplier when they change the GCR or tilt angle.

A more accurate estimate would take into account tilt angle and ground coverage ratio (GCR):

Adjusted Module Area = Total Module Area / GCR * COSINE( Tilt Angle )

Land Area Estimate = Adjusted Module Area * Land Area Multiplier + Additional Land Area

Note that PVWatts module area estimate currently includes GCR while Detailed PV does not.

Missing UI group label for PVWatts: