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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
>



===============================================================================
  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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