Some words from the field

[ZiaCache]

Thanks for setting this up, Jeremy & Elias. We have been chasing these things for several months since someone set up the NM Benchmark Recovery Cache page.

 

By reading the text on the Benchmark pages from NGS, we found old ones along an abandoned highway - which led to a regular cache hidden along the route. We still have five to go to complete the old righ of way.

 

Anyway, something we have found is that Benchmarks from the 20's & 30's are seldom near the published coordinates (at least in our area). Be prepared to search a considerable area - the worst was nearly a quarter mile off. Be sure and print out the descriptions - they are sometimes easier to follow than the coordinates.

 

With a scarcity of regular caches in SE NM, benchmarking has been a great way to play.

 

To get an idea of how folks have gotten involved, check out the NM Benchmark Recovery Cach Page:

http://www.geocaching.com/seek/cache_details.asp?ID=12355

 

Jim

Team ZiaCache

[+Web-ling]

quote:

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Originally posted by ZiaCache:

...Anyway, something we have found is that Benchmarks from the 20's & 30's are seldom near the published coordinates (at least in our area). Be prepared to search a considerable area - the worst was nearly a quarter mile off. Be sure and print out the descriptions - they are sometimes easier to follow than the coordinates...

 

Jim

Team ZiaCache

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I've found that the USGS maps from Topozone often have the location marked for benchmarks, and the ones I've hunted so far have been right on the money. Use the location on the actual map, NOT the crosshairs added by Topozone.

 

[ZiaCache]

I'm not using maps, just GPS. Some of the published coordinates on the NGS site (and now this site) are way off- some as much as 1/4 mile. I found one the other day by accident that NGS shows to be 12 miles from its actual location. Just about all of the ones we have found that were monumented in the 20's & 30's AND not reported since are quite some distance off. Probably early surveying errors. Many that have been recovered in the past several years are accurate - probably checked by GPS by the NGS recovery crew. That's why I suggested to print out the directions from the list or NGS - it can be way more accurate than the GPS for old marks.

 

I never pay any attention to Topozone - it showed one of our caches about halfway down a 500' sheer cliff face! www.lostoutdoors.com mapmaker seems to be more accurate.

 

Jim

Team ZiaCache

[iryshe]

The benchmark has a horizontal and vertical accuracy that is documented on each benchmark page (and is noted beneath the coordinates). If you click on the details the measurements are at the bottom of that page.

 

Jeremy

 

Jeremy Irish

Groundspeak - The Language of Location

[+Web-ling]

quote:

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Originally posted by ZiaCache:

 

I never pay any attention to Topozone - it showed one of our caches about halfway down a 500' sheer cliff face! http://www.lostoutdoors.com mapmaker seems to be more accurate.

 

Jim

Team ZiaCache

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TopoZone uses different datum, so the coords are often WAY off, unless you convert them first. However, many of the benchmarks are shown on the original maps that TopoZone scanned to create their website, and the ones I've seen have been right on the money.

 

LostOutdoors.com is usually VERY accurate. I've literally had the dot show up exactly on the correct tree or other object, which is a lot better than my GPSr usually does in heavy tree cover.

 

So far, I haven't used my GPSr to find any of the 10 benchmarks I've located. I've strictly used TopoZone maps, MapBlast maps, and LostOutdoors aerials in conjunction with the benchmark descriptions. I have used the GPSr to log the correct coordinates.