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Just before I got this message I was going to write... "We need a
Wikki maps initiative."  Great minds think alike.  Crowd sourcing has
powerful implications.
Thomas A. Sult, MD
3rd Opinion
1415 First First St. South #5
Willmar, MN 56201
320 235 2101 Office
www.3rdOpinion.us
tsult@mac.com






On Nov 14, 2010, at 10:07 AM, Richard B. Langley wrote:

> One way to update maps, at least electronically, is though
> volunteered geographic information--getting the public to supply
> updates. Issues related to this activity are reviewed in this paper:
> .
> -- Richard Langley
>
> Quoting Apache Runner :
>
>> Peter -
>>
>> This is all preaching to the choir, I suppose.  Most folks on this
>> list
>> probably know how far one can trust a map, but I do appreciate you
>> sending
>> around the column that woman wrote.
>>
>> I might add an addendum to the various thoughts, and even a
>> response to her
>> essay that I suppose will never reach her, but it's something like
>> this:
>>
>> Consider what it takes to create a map.   You have to start with a
>> well-surveyed control network.   In the modern era, you lay on top
>> of that
>> aerial stereo photographs to get the major topographic features.
>> Then you
>> have whatever local knowledge you can put on top of that to extract
>> paths
>> that may be hidden from view in the aerial photographs.
>> Presumably paved
>> roads have blueprints that lay out their path relative to the control
>> network.   All of this is a lot of work.   I know some land
>> surveyors and
>> they'll tell you how difficult it is to find some markers on the
>> secondary
>> control networks.   Sometimes, it's a half buried bottle hidden by
>> a bush.
>> In the particular case of the missing dirt track, washouts happen
>> all the
>> time, and some aspects of the landscape change far faster than
>> surveyors and
>> cartographers can keep up with it.
>>
>> All of these are good reasons to consult the date of creation of
>> the map and
>> the revision history.
>>
>> Now that I think about it, I have to grab some maps myself.   Has
>> anyone on
>> this list been to Rollright?   Know anything about astronomical
>> alignments
>> of it (or lack thereof?).   I'm visiting there in a couple of weeks
>> and am
>> trying to sort through the literature.   Talk about reverse
>> engineering -
>> going back 10 years is one thing, but 4500 is quite another.
>>
>> John H.
>>
>>
>>
>>
>> On Sun, Nov 14, 2010 at 4:39 AM, Jackie Ferrari
>> wrote:
>>
>>> I have used them extensively hiking around the Highlands of
>>> Scotland.
>>> Once looking for a particular forest in which to camp, I was
>>> convinced my
>>> navigation was wrong as I could see no forest where my 1:50000
>>> Ordnance map
>>> told me it should be. Nonetheless I kept on the path(a sheep
>>> track) and lo
>>> and behold ,there it was. A plantation of 6 inch high conifers.
>>> However on occasion, forest tracks marked on the map are no longer
>>> there,
>>> but these have always been man made tracks, made by bulldozers for
>>> clearance. It seems the sheep tracks are more 'permanent.' !
>>>
>>> Jackie.
>>>
>>> ----- Original Message -----
>>> *From:* Apache Runner 
>>> *To:* NavList@fer3.com
>>> *Sent:* Sunday, November 14, 2010 4:07 AM
>>> *Subject:* [NavList] Re: An essay about maps
>>>
>>> Certainly, the USGS topo's are far out of date with respect to
>>> tracks -
>>> hiking and passable 4-wheel-drive routes.  I've found too many out
>>> of date
>>> instances to recount.
>>>
>>> On Sat, Nov 13, 2010 at 6:00 PM, Fred Hebard  wrote:
>>>
>>>> Are the British Ordnance Survey maps really as accurate as she
>>>> claims?
>>>> I've never seen a high resolution (<= 30') map that was 100%
>>>> accurate,
>>>> where I had knowledge enough of the terrain to detect the errors.
>>>>
>>>> It was rather a nice read, thanks for sharing it.
>>>>
>>>>
>>>> On Nov 13, 2010, at 4:43 PM, Peter Fogg wrote:
>>>>
>>>> An essay for those interested in maps:
>>>>>
>>>>> http://www.smh.com.au/opinion/society-and-culture/road-to-nowhere-20101112-17r37.html
>>>>>
>>>>> You can tell the good lady is from the Big Smoke.  If she'd
>>>>> spent more
>>>>> time in remote places she'd have known that when you get to a
>>>>> place like
>>>>> Hungerford you don't just drive through it.  You stop and, first
>>>>> of all,
>>>>> take on fuel.  Even if your tanks are near-full - whether you'll
>>>>> find any
>>>>> more further on is never guaranteed, and the person selling fuel
>>>>> is
>>>>> potentially a good source of information about what lies ahead.
>>>>> Then you
>>>>> visit the pub.  If the place is a stepping-off point to really
>>>>> remote places
>>>>> you're also expected to register with the cops.  Its just common
>>>>> sense
>>>>> really, but you can expect to be quizzed about how well-prepared
>>>>> you might
>>>>> be for the next leg, including your mapping resources.
>>>>>
>>>>> As you drive out from the relatively well-populated coast into the
>>>>> relatively bereft-of-people interior, you go from ignoring other
>>>>> motorists
>>>>> to acknowledging them.  Then when you get further out, if
>>>>> another vehicle
>>>>> approaches from the direction you're going then you both stop -
>>>>> blocking the
>>>>> road, but that's rarely a problem - so the drivers can have a
>>>>> leisurely
>>>>> chat, driver's window to driver's window, elbow to elbow, about
>>>>> the weather
>>>>> and the price of ewes and, what interests you most, what's ahead.
>>>>>
>>>>> In two words: local knowledge.  The good lady is dreaming with her
>>>>> whimsical insistence on mapping accuracy.  As if there was such
>>>>> a thing.
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>> --
>>> Keeping up with the grind
>>>
>>>
>>
>>
>> --
>> Keeping up with the grind
>>
>
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> ======================================================================
> Richard B. Langley                            E-mail: lang@unb.ca
> Geodetic Research Laboratory                  Web: http://www.unb.ca/GGE/
> Dept. of Geodesy and Geomatics Engineering    Phone:    +1 506
> 453-5142
> University of New Brunswick                   Fax:      +1 506
> 453-4943
> Fredericton, N.B., Canada  E3B 5A3
>     Fredericton?  Where's that?  See: http://www.city.fredericton.nb.ca/
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