C182 PLT HAS AN NMAC AT APA.

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I TAXIED TO RWY 17R; FOLLOWING A C172 A WAYS IN FRONT OF ME. APA ARPT WAS NOT PARTICULARLY BUSY AT THE TIME. RWY 17L WAS CLOSED FOR REPAVING; AND TAXI TO RWY 17R WAS REQUIRED (NOT A NORMAL OP AT APA). I WAS TOLD TO TAXI TO THE HOLD LINE; AND MONITOR TWR. THE ACFT IN FRONT OF ME WAS CLRED FOR TKOF; AND APPARENTLY PLANNED TO DO PATTERN WORK. HE WAS TOLD TO STAY IN PATTERN AND 'MAKE CLOSED TFC.' SHORTLY AFTER ARRIVING AT THE HOLD LINE; I WAS INSTRUCTED TO 'TAXI INTO POS AND HOLD.' ACFT Y HAD JUST TAKEN OFF 1 MIN OR SO EARLIER. ANOTHER MIN OR SO PASSED; AND I WAS CLRED FOR TKOF. PRIOR TO TAXI; I HAD REQUESTED A NW DEP FROM GND CTL. ALONG WITH THE TKOF CLRNC; THE TWR ALSO CLRED ME FOR A NW DEP WITH 'NW DEP APPROVED.' HOWEVER; THE CTLR ALSO GAVE ME AN INSTRUCTION TO 'FLY CLR OF THE PATTERN.' I WAS UNCLR WHAT HE ACTUALLY MEANT WITH THAT LAST INSTRUCTION; AND SHOULD HAVE ASKED FOR CLARIFICATION; BUT I TOOK IT TO MEAN 'EXIT PATTERN WHEN ABLE; AND DEPART NW.' I TOOK OFF FROM RWY 17R USING THE STANDARD TKOF PROC FOR THE C182. I TURNED XWIND AT NORMAL PATTERN DISTANCE AND ALT; WHICH I LATER VERIFIED FROM MY GPS RECORDED TRACK. APPARENTLY; ACFT Y HAD FLOWN AN EXTENDED PATTERN; POSSIBLY BECAUSE OF THE HIGH DENSITY ALT THAT DAY AND THE RELATIVELY LOW PERFORMANCE OF THE C172. I ESSENTIALLY OVERFLEW ACFT Y -- HIM ON DOWNWIND AND ME ON XWIND. I WAS VERY SHOCKED TO SEE HIM OFF OF MY L WING -- I THOUGHT HE WOULD BE WELL IN FRONT OF ME IN THE PATTERN; AND NO FACTOR. THE CTLR NOTICED SHORTLY AFTER THE NEAR MISS (LESS THAN 200 FT HORIZ AND LESS THAN 100 FT VERT); AND COMPLAINED THAT I DIDN'T FOLLOW HIS INSTRUCTIONS. TO BE HONEST; I STILL DON'T UNDERSTAND THE INSTRUCTION TO 'FLY CLR OF THE PATTERN.' IT SEEMS VERY AMBIGUOUS; AND DID NOT ADEQUATELY CONVEY WHAT THE CTLR REALLY WANTED. IN RETROSPECT; I BELIEVE HE WANTED ME TO CONTINUE FLYING UPWIND FOR ANOTHER MI (OR MORE?) BEFORE TURNING W; INSTEAD OF JUST TURNING A STANDARD XWIND. I WOULD FAR PREFER THE INSTRUCTION 'FLY RWY HDG; I'LL CALL YOUR TURN.'