BE36 PLT INTERCEPTED BY GOV AGENCY AND FORCED TO LAND WHERE ADVISED OF NY ADIZ VIOLATION. PLT USED GPS FOR AIRSPACE PROTECTION THAT DID NOT IDENTIFY MODE C VEIL/ADIZ.

Narrative

I WAS RETURNING VFR FROM MFV TO 3B9 VIA ACY AND CCC. I WAS FLYING N ALONG THE NEW JERSEY COAST AT 6500 FT AND NAVIGATING WITH A GPS. FIFTY MILES S OF JFK; I CHANGED COURSE TO FLY DIRECT TO THE CCC VOR. THE GPS RED COURSE LINE SHOWED ME CLRING THE JFK CLASS B AIRSPACE BY A GOOD MARGIN. I MISTAKENLY THOUGHT THE GPS DISPLAYED THE MODE C VEIL AROUND NY AND THAT I WAS WELL CLR OF THE TFR AROUND NY. PAST CCC AND OVER LONG ISLAND; I WAS INTERCEPTED BY A GOV AGENCY ACFT AND TOLD TO DIVERT. ONLY THEN; DID I REALIZE THAT I HAD DONE SOMETHING WRONG. THE HOMELAND SECURITY PLT WAS ALSO USING A GPS AND EXPLAINED HOW IT DID NOT DISPLAY THE MODE C VEIL. SINCE THE GPS DISPLAYED ONLY THE CLASS B AIRSPACE; I CLRED THE CLASS B; BUT PIERCED THE TFR WHILE ENRTE TO CCC. IT WAS MY ERROR. NEVER ASSUME. IN THE FUTURE; I WILL KNOW MY EXACT LOCATION WITH GREATER PRECISION AND CARE. I ATTEND FAA SAFETY SEMINARS AND PARTICIPATE IN THE FAA WINGS PROGRAM. I TRY TO BE A CONSCIENTIOUS AND SAFE PLT. THE ERROR WAS MINE AND I LEARNED A VALUABLE LESSON.