About the 2015 Halfmile Updates

Updating maps for 2015

Updating maps for 2015

The 2015 Pacific Crest Trail hiking season is rapidly approaching and understandably we have been getting questions about what’s changing in the 2015 edition of Halfmile’s PCT maps and when new maps, apps and GPS data will be ready.

2014 was a massive data collection effort for the Halfmile Project team. Halfmile and Dirt Stew thru-hiked the PCT (Halfmile northbound, Dirt Stew southbound) carrying very accurate custom GPS devices designed for mapping long hiking trails. 8,296,179 new data sample points and 5,065 new waypoints were collected.

GPS reception can be challenging along some parts of the PCT due to tree cover or terrain such as mountains or canyons that sometimes block GPS signals. This is especially true in Oregon and Washington. The custom GPS logging hardware performed amazingly well because of the outstanding performance of the ublox NEO-7P GPS module, external mast mounted antennas, and the merging of multiple GPS data sets using software developed by David Lippke. We are confidant this is the most accurate data ever collected of the PCT.

Overall the new 2015 data has an average horizontal accuracy of 1.9 meters. Here is the horizontal accuracy by PCT section:

CA Sec A: 0.67 meters
CA Sec B: 1.26 meters
CA Sec C: 1.11 meters
CA Sec D: 1.19 meters
CA Sec E: 0.81 meters
CA Sec F: 0.98 meters
CA Sec G: 1.18 meters
CA Sec H: 1.44 meters
CA Sec I: 1.62 meters
CA Sec J: 1.51 meters
CA Sec K: 1.61 meters
CA Sec L: 0.49 meters
CA Sec M: 0.57 meters
CA Sec N: 0.46 meters
CA Sec O: 0.68 meters
CA Sec P: 1.92 meters
CA Sec Q: 2.37 meters
CA Sec R: 2.19 meters
OR Sec B: 2.66 meters
OR Sec C: 2.49 meters
OR Sec D: 2.57 meters
OR Sec E: 2.32 meters
OR Sec F: 2.45 meters
OR Sec G: 3.78 meters
WA Sec H: 3.45 meters
WA Sec I: 2.94 meters
WA Sec J: 1.75 meters
WA Sec K: 3.34 meters
WA Sec L: 2.42 meters

Note that 1-sigma accuracy calculation are used which are about 20% more stringent than the CEP (Circular Error Probability) accuracy calculations used by Garmin GPS units.

Sharp-eyed readers may be wondering about the phenomenal accuracy of California sections L, M, N, and O. These sections were logged separately using a survey grade Trimble GPS.

On a printed map where 1/16th inch equals 50 meters hikers are unlikely to notice the extra accuracy of this data, but it does allow the Halfmile Project team to more accurately estimate the length of the PCT. We have calculated new mileage estimates of the PCT for 2015.

We now estimate the length of the PCT (from the Mexican border to Manning Park, BC) to be 2,658.9 miles (compared to 2668.8 miles in our old estimates). Note that the 2015 mileage estimates no longer include the Crater Lake Rim Trail. The Crater Lake Rim trail is a highly recommended alternate, but in the past few years the National Park Service has removed all the PCT signs from the Rim Trail and it is clearly no longer part of the official PCT. The Rim trail alternate is about 3.9 miles shorter than the actual PCT.

These new, more accurate, mileage estimates mean hikers need to be careful not to mix 2014 and 2015 Halfmile data because the mileages will not match.

Other changes:

The 2015 Halfmile maps, apps, and GPS data now have more than 3,160 waypoints for PCT landmarks such was water sources, trail junctions and campsites. This is about 1,060 more than last year. Most of these new waypoints are in Northern California, Oregon and Washington. This is a very significant improvement in the 2015 data.

The 2015 data includes 130 side trails and alternate trails in addition to the 30 main PCT sections.

This is all great Halfmile, but when will the new maps, apps, and other data be ready?

It’s been massive amount of work processing all this new data and more work still remains to be done. We are making steady progress.

Today we are releasing the “2015 Preview Edition” of Halfmile data as a Google Earth KML file.

California PCT Section A – H maps (Campo to Yosemitte) have been uploaded and are now online. California PCT Sections A, B, E, F, G, and H maps have only minor updates compared to 2014.

Maps of all California PCT sections should be ready around the end of February. Oregon and Washington PCT maps should be ready a few weeks after that.

GPS data and the final Google Earth KML file should be ready around the end of February.

Halmile’s Trail Notes should be ready early in March.

Halfmile smartphone apps will be updated in March.

Monitor the PCTmap What’s New page to see exactly what’s been updated.

I’m a hiker with older Halfmile maps, what should I do?

Thousands of hikers have successfully hiked the PCT using the older Halfmile maps and we are sure you will be just fine too. Hikers should be careful not to mix 2014 and 2015 data since they will not match. We plan on developing tools for converting between 2014 and 2015 mileages. Check back for details on that.

Related Links:
Halfmile’s PCT iPhone app
Halfmile’s PCT Android app
PCTA.org: Ultra-high tech mapping the PCT
Herald.net: Hikers spend summer logging Pacific Crest Trail in hopes of improving app
Dormouse and Dirt Stew’s Blog