[pct-l] Data Book Discrepancies

Dan C. aka Thumper dofdear at cox.net
Wed Jun 11 11:54:31 CDT 2014


While I'm not surprised this conversation has become personal it is disappointing. Particularly from a successful hiker who really appreciates the data. 

What is clear to me is that both Halfmile's and Postholer's data is 'correct' and accurate. So how can they both be correct and different at the same time. Well that's easy. The source infomation and technical processes are different.  

Halfmile uses GPS tracks he and others collected, and then put them through rigorous processes to produce his maps.  His process is as accurate as the GPS equipment and hikers used. I find it interesting that Halfmile is currently hiking with a professional surveyor type accurate GPS in an effort to increase confidence levels.

In Postholer's case he is using officially published data sources including the USFS kmz files and other geospatial data sources. He employs recognized processes to calculate distances and elevation. 

Personally I find both map sets have benefits with Postholer's easier to read in the field plus the accompanying data book. But Halfmile's map tracks may in a few cases be closer to the actual trail. But 10 miles in some ~2680 miles is pretty close.

I know both of these hikers. They have character and most importantly, integrity. They both respect and obsess over data. Either map set will work well.

Interesting is that of late Google Maps displays a trail track of the PCT and many other trails.  Wonder what their source was? Bet not Halfmile (just my opinion). Suspect they are using an authoritative source, although if they are documenting trails like they did roads I'll be applying for work as a Google Hiker.

Finally, it is not the PCTA's charter or responsibility to adopt a standard. For that we should look to the USFS, BLM and the other maping agencies. 

Thumper



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