[Geysers] Mapping Help

Steven Krause S_Krause at mchsi.com
Mon Nov 11 19:07:06 PST 2013

Never give up data.

Rounding simply increases your error. That lat/long position may only 
have an accuracy of 5m, but if you discard another 200mm of precision, 
you've degraded your measurement permenantly.

Add in coordinate system conversions, which usually degrade the number a 
bit more.....

Steve Miller's post is a good technical description of what was done and 
explains how you triangulate in on a feature you can't touch. It's a 
moderately common practice even with high precision RTK equipment.

As an aside: Lack of understanding of another profession is never a good 
excuse to snark.

Steve Krause

On 11/11/2013 2:17 PM, TSBryan at aol.com wrote:
> I seem to recall that Mike Keller accompanied the SCA people during 
> some of the mapping program. If so, maybe he can elucidate us as to 
> just how and why certain survey positions were chosen. (Example 1: 
> Were the coordinates always taken at [say] the southernmost extreme of 
> a feature? Example 2: Were the coordinates always determined at some 
> specified distance away from the edge of a feature? etc.]
> All this kind of stuff in mind, where is the justification for 
> coordinates cited to 7 (seven ! ) decimal points? Strikes me as vast 
> overkill. At Yellowstone's latitude (and with this, I'll stick to 
> latitude because it's a bit easier), one degree of latitude is 
> equivalent to just about 69.055 miles. That is 364,610 feet. Multiply 
> that by 0.0000001 gives 0.0364 feet, and that means these coordinates 
> are supposedly accurate to within a touch more than 0.43 inch. Really?
> Scott Bryan
> In a message dated 11/11/2013 10:30:07 A.M. US Mountain Standard Tim, 
> david.schwarz at alumni.duke.edu writes:
>     As a result, many of the coordinates that year were only taken
>     within roughly the same long-distance dialing area as the feature
>     being mapped.  Obviously, it doesn't matter how accurately the
>     equipment pinpoints your location if you're not particularly close
>     to what you're trying to map.
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Steven Krause
Chillicothe, IL

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