Philmont Waypoints Corrections


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Date: Fri, 28 Jun 2002 14:01:53 -0500
From: Tim Osborn <tosborn@sbcglobal.net>
Subject: Philmont GPS Waypoints
The other day I came across your "Philmont Waypoints" page on the Internet ( http://w4.lns.cornell.edu/~seb/philmont-waypoints.html). Let me congratulate you on posting this information. I think it can be a great planning tool for Scouts to use prior to their trip to Philmont, as well as during their trek.

In reviewing your list I have come across two waypoints that I know are in error, and several others that I think are suspect. However, most seem to be fairly accurate.

The most inaccurate waypoint is the one for Rimrock Park. I'm sure this is just a typo. The coordinates you list are 39°22'28" latitude, and 105°00'58" longitude. This is about 207 miles north of the true position. The degree number for the latitude should be 36 degrees, not 39 degrees.

The other inaccurate waypoint that I'm sure about is for the Tooth of Time. You list it as 36°26'05" latitude, 105°00'26" longitude. This point is about 0.9 miles south of the Tooth. The correct coordinates should be 36°26'54" latitude, 105°00'26" longitude.

There are 7 other waypoints that I think may be off by 0.6 to 1.1 miles from their actual location. I say "think" because my basis for comparision is the locations as shown on USGS topographic maps of the area, and I know that there are sometimes differences between the USGS maps and the big Philmont wall map.

Aguila Camp
Your coordinates (36°24.92', 105°01.33' )
USGS topo coordinates (36°23.944', 105°01.370' )
Difference 1.1 miles

Rayado Camp
Your coordinates (36°22'08" ,10456'55")
USGS topo coordinates (36°23.139', 104 55.830)
Difference 1.0 miles

Pueblano Ruins
Your coordinates (36°37.80', 105°08'04")
USGS topo coordinates (36°37.743', 105° 08.095')
Difference 0.7 miles

Sioux Camp
Your coordinates (36°37'30", 105°03'58")
USGS topo coordinates (36°37.474', 105° 03.288')
Difference 0.6 miles

Upper Dean Cow Camp
Your coordinates (36°36.17', 105°04'45")
USGS topo coordinates (36°36.167', 105° 05.410')
Difference 0.6 miles

Ute Meadows
Your coordinates (36°37'12", 105°10'16" )
USGS topo coordinates (36°37.251', 105° 10.930')
Difference 0.6 miles

You might want to double check these waypoints. It's quite possible that you have the correct locations and the USGS topo maps are wrong.

Finally two other suggestions. You should state at the top of your web page the DATUM the waypoints are based on. I'm assuming it is NAD27 CONUS which is the datum used for most USGS topographic maps. The other primary datum in use for the United States is WGS84 (NAD83 is nearly identical with WGS84). Although the error imposed by using the wrong datum is only about 85 feet east or west in the Philmont area, the datum really should be stated.

The other suggestion is that the waypoints be expressed using a consistent format throughout the page. Most the waypoints are listed in degree-decimal minute format. But some have degree-decimal minutes for the latitude, and degrees-minutes-seconds for the longitude. Still others are expressed in all degrees-minutes-seconds. This means the user has to keep changing the coordinate input format on their GPS or mapping software.

Thanks

Tim Osborn
tosborn@sbcglobal.net


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The content of this Web page was provided by Tim Osborn. Please contact him at <tosborn@sbcglobal.net> for more information.

This Web page is maintained by Selden Ball at Wilson Lab.
Please send any comments or corrections to seb@lns.cornell.edu