Pin 1 is the notched pin.

Pin 1 GND 1 Ground
Pin 2 +VOUT 2 + Voltage output
Pin 3 VS 3 Power supply
Pin 4 –VOUT 4 – Voltage output

Supply voltage 3V typical (6 max)
Supply Current 6 mA

Note that some temperature compensation may be required over large temperature spans.

P1>P2  P1 identified as side with part marking.  Fig 12 shows with pin one facing left, P1 is port on right.  Closer examination of actual parts shows, P1 is the port closest to Pin 4.  

Review of the AN1318 application note shows that V-out (Pin 4) is not required to be connected to the microcontroller.