[Geysers] Mapping Help

[David Schwarz]

I was just going to let this go, but since people I've never met and who
weren't there seem to have developed opinions about what I do or don't
understand:

First, I never worked with Steve--on that point he is mistaken.  I never
met him until years after I had done my stint as a guide for the GIS crew,
so whoever he remembers "running off exploring" wasn't me or the other
guide from 1998.  We stayed close to the crew as a matter of safety.

Whatever procedures were developed in later years, the crew I worked with
was brand new at the time, and had little-to-no direction from management
on which features were significant enough to map, how close was "close
enough," or how to deal with anything large, unapproachable, or densely
clustered--which ended up being a good chunk of what we were sent to
inventory.

Certainly no process remotely approaching the sophistication of what Steve
discussed was in play.  There was no effort to correct for how close we
could stand to a given feature.

This was, all-around, a case of rookie staff having to make calls in the
field as best they could.

On top of that, the equipment was finnicky, and at times it took upwards of
15 minutes to get signals from enough satellites to map a single point.
Those were early days for non-military GPS.

I don't mean to detract from the careful work, sweat, and tears that went
into the project over the succeeding decade-plus, or from the overall
quality of the final product--and I apologize to Steve and the rest of the
GIS Lab staff if I offended them with my hyperbole.

But I do stand by my assertion that lingering data from 1998 (if any was
allowed to stand) could explain some bad coordinates in the mix, and, for
reasons I don't feel like getting into on a public forum, I also stand by
my right to be snarky about it.

David Schwarz
 On Nov 12, 2013 7:45 PM, "Steven Krause" <S_Krause at mchsi.com> wrote:

>  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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