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Adventure 3
Finding Corners


Many historic sites have "corners." Land divisions have corners. Sometimes these corners can be very interesting although I suppose the level of interest depends on the individual. My son-in-law Bob says the day he and I spent looking for corners was hardly a memorable adventure! Old corners such as those that define a mining claim, are often obliterated.

What kinds of corners can you expect? Trees with a blaze are my favorite. I will show you an example. In the 1882 mining survey map below, the Canon Placer Claim is deliniated by a series of corners.


Translations:
Post in rock m'd. "C.P.C. No. VII" means a wooden post marked "C.P.C. No. VII" is in a rock mound

Spruce "C.P.C. No. VIII" means a spruce tree was marked "C.P.C. No. VIII"

N. 66° E. 349.8 ft or 5.30 chs. means the bearing between the two points is 66 degrees east of true north and the distance is 349.8 feet which is equivalent to 5.30 chains.

I walked this claim looking for the corner trees. Below you will see a picture of Spruce "C.P.C. No. VIII" which shows a stump with the letters "C. P. C. No" visible sideways. Keep in mind that an adult tree was blazed in 1882 so it is not surprising that it is a stump today.



In the next picture you will see the rotten remains of Spruce "C.P.C. No. VIII" and the modern USFS monument that replaces it.


More on GPS corner location

I recently did an experiment on nearby Table Mountain. I wanted to see how difficult it was to find a needle (section corner) in a haystack (the flat top of Table Mountain). In the map below you will see two dark circles. Within the circles are the desired section corners.




I used two GPS techniques:
Without Signal Averaging
I entered the UTM coordinates (623880E by 438270N) estimated from the map into the navigation goal in the GPS unit. I then navigated to the site. This is easy when you are far from the site--the GPS shows you what direction to head and how far it is to the goal. However, when you get close (ca 500 ft) the Selective Availability (SA) induced error of plus or minus 100 meters makes navigation difficult. You find yourself "navigating in circles." At this point I stopped and began a big, circular search around the stopping point. It took me an hour to find the small mound of rocks and the monument.
With Signal Averaging
Next I entered the coordinates (622340E by 438240N) of the next section corner. I navigate to it as before but when I stopped, rather than searching for the point, I started the signal averaging feature of the GPS. This feature averages the incoming values to give a better solution to the coordinates. A 20 meter solution is possible if you wait 15 minutes and a 10 meter solution can be achieved in 60 minutes.

I sat down and had my lunch. I gave the GPS about 20 minutes to average. Then I used the "from A to B" navigation feature. I entered the 20 minute average position as "A" and the desired position as "B" and the GPS calculated that the corner was 335 feet away at 285 degrees true. I then used a compass and walked right to the monument.

Technology is amazing n'est-ce pas?

Take me to the top

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