SMA PLT MISREADS ALTIMETER FLIES 800 FT OVER POPULATED AREA.

Narrative

I WAS RETURNING FROM LONG BEACH ARPT VFR USING THE LOS ANGELES RIVER FOR PILOTAGE ON A 20 MIN FLT TO WHITEMAN AIRPARK (WHP). I WAS BUSY READING THE LAX TCA MAP TO AVOID CLASS B AIRSPACE AND MISREAD MY ALTIMETER. I THOUGHT I WAS AT 1800 FT MSL WHEN IN REALITY I WAS AT 800 FT MSL. I DID NOT DISCOVER MY MISTAKE UNTIL I CALLED BUR CLASS C FOR TRANSITION AND THEY ADVISED ME TO CHK MY XPONDER AND ALTIMETER BECAUSE OF THE LAST READING. UPON REALIZING MY MISTAKE I INITIATED A CLB TO 1800 FT. I WAS SUBSEQUENTLY CITED BY LAX POLICE DEPT HELI FOR 21407 P.U.C. RECKLESS FLYING. SOME OF THE FACTORS THAT CONTRIBUTED TO THIS ERROR WERE: 1) UNFAMILIAR WITH THE LAX BASIN AREA. 2) PREOCCUPATION WITH AVOIDING CLASS B AIRSPACE. 3) BEING BASED AT A 1000 FT MSL ARPT VERSUS LGB AT 27 FT MSL. 4) THE STRESS FACTOR OF JUST COMPLETING A CHK RIDE. 5) QUITE A FEW HRS OF PREPARING FOR A CHK RIDE FLYING AT 700-900 FT ABOVE THE GND. I THINK THIS CAN BE AVOIDED BY MAKING SURE TO BE IN THE PROPER FRAME OF MIND FOR FLYING NO MATTER WHAT KIND OF FLT IT IS. ALSO EVALUATING THE STRESS FACTORS AND THE TIME IT MAY TAKE TO ALLEVIATE THEM BEFORE FLYING.