There is an old poem by A.A. Milne that I love because of its logic puzzle.
Halfway Down
by A.A. Milne 1924 1
Halfway down the stairs
is a stair
where i sit.
there isn't any
other stair quite like
it.
i'm not at the bottom,
i'm not at the top;
so this is the stair
where
I always
stop.
Halfway up the stairs
Isn't up
And it isn't down.
It isn't in the nursery,
It isn't in town.
And all sorts of funny thoughts
Run round my head.
It isn't really
Anywhere!
It's somewhere else
Instead!
by A.A. Milne 1924 1
Halfway down the stairs
is a stair
where i sit.
there isn't any
other stair quite like
it.
i'm not at the bottom,
i'm not at the top;
so this is the stair
where
I always
stop.
Halfway up the stairs
Isn't up
And it isn't down.
It isn't in the nursery,
It isn't in town.
And all sorts of funny thoughts
Run round my head.
It isn't really
Anywhere!
It's somewhere else
Instead!
One of the aspects of the poem is: "How do you know WHERE you are"; which leads to all sorts of interesting problems and issues.
Trying to locate WHERE is a very old problem, probably as old as when the first hominids realized they could bludgeon another hominid to claim the spot that one was sitting on. Watching our cats sort out their eating bowls is much the same. They all get the same food but somehow they just "know" that the food in that OTHER dish is better. They rotate around the bowls sampling the same fare.
The odd thing about WHERE, is that we both know and we don't know. I know where my pile of dirt IS but I don't know WHERE it is. There is a significant difference between the two.
The main method humans use to determine WHERE are maps. Wolves just pee their territory markers and other wolves recognize the claim, but humans are sadly lacking in that olfactory department and peeing isn't recognized as a legal marker. So we use maps.
And there in lies a problem.
'Cause all maps are unequal
Some maps are more unequal than others
But only on Tues and Thurs
There are many sorts of maps, all attempting to solve one or more problems with WHERE.
Paper street maps show the approximate location and direction to any street within the grid area. Section A47 leads to block on the map where the street names are listed. It is not accurate. It's representational.
GPS systems have an average error of 50 ft., but they can be off by as much as a 100 ft. in WHERE. 2 Given that modern humans rely on this imprecise information for auto-navigation systems , it's surprising anyone wants a self-driving car that can miss the road by 100 ft. and driving across the Rio Grande Gorge Bridge3 600 ft. above the Rio Grande River might lead to quicker decent than anticipated if the car misses the roadway by even a few feet.
There is another niggly problem with WHERE and that is the earth is round-ish. There are maps that try to answer: "How do you make a round object into a flat surface?" It's rather like an orange and there are variations on how to peel it. Geographers and Cartographers have been working on this for a long long time.
For the rest of us it's a bit like Le Petit Prince's encounter with the Geographer 4. The Geographer knows nothing about the planet because all he does is write down what explorers tell him.
Le géographe ne quitte pas son bureau .... 4
So, where IS where?
For my hunk of dirt the only map that counts is a Cadastre Survey Map.5
A cadastre survey map marks the legal boundaries and corners of land parcels. While it has been around for centuries, but it's only since I've owned the pile of dirt, that I've learned about it. Knowing WHERE the boundaries and corners are, is an important way to avoid boundary clashes over fence lines and distance requirements. My dirt pile requires a 30 ft. fire break around the perimeter and a cadastre map will show where to measure that distance. It will allow the proper distance measurements between the house, well, septic and PGE power poles.
Now, given that the lot has been pretty much there since dirt was invented, one might think that this was a done-deal and it would be documented somewhere.
It is and it isn't.
Deed and title show the legal owner of what IS, and a previous cadastral map can show where the WHERE was; but you need something on the physical dirt to actually link both the "WHERE" and "IS" together.
Those physical markers are called milestones, boundary markers, survey markers, survey monuments or corner markers.6 Each has a purpose and is used to define the WHERE between two or more geographic areas.
So... why isn't a historical corner marker good enough?
Because someone with a bulldozer:
- dug it up
- moved it
- buried it
- excavated it
or - it was trashed and sent to some landfill.
On my dirt pile I have 5 markers.
2 have been found.OH CADASTRE!
3 are missing.
References
- https://en.wikipedia.org/wiki/Halfway_Down_(poem)
https://en.wikipedia.org/wiki/A.A._Milne - https://en.wikipedia.org/wiki/Global_Positioning_System
https://en.wikipedia.org/wiki/Error_analysis_for_the_Global_Positioning_System
Autonomous civilian GPS horizontal position fixes are typically accurate to about 15 meters (50 ft.) - https://en.wikipedia.org/wiki/Rio_Grande_Gorge_Bridge
The Rio Grande Gorge Bridge, locally known as the "Gorge Bridge" or the "High Bridge... Roughly 600 ft. above the Rio Grande, it is the tenth highest bridge in the United States. - https://en.wikipedia.org/wiki/The_Little_Prince
https://fr.wikipedia.org/wiki/Le_Petit_Prince
Le géographe est trop important pour flâner. Il ne quitte pas son bureau. Mais il y reçoit les explorateurs. Il les interroge, et il prend en note leurs souvenirs. - https://en.wikipedia.org/wiki/Cadastre
A cadastre (also spelled cadaster) is a comprehensive land recording of real estate to define the dimensions and location of land parcels described in legal documentation - https://en.wikipedia.org/wiki/Milestone
A milestone is one of a series of numbered markers placed along a road or boundary at intervals of one mile or occasionally, parts of a mile
https://en.wikipedia.org/wiki/Boundary_marker
A boundary marker, border marker, boundary stone, or border stone is a robust physical marker that identifies the start of a land boundary or the change in a boundary, especially a change in direction of a boundary. There are several other types of named border markers, known as pillars, obelisks, and corners.
https://en.wikipedia.org/wiki/Survey_marker
Survey markers, also called survey marks, survey monuments, survey benchmarks or geodetic marks, are objects placed to mark key survey points on the Earth's surface.
 |
| Missing Survey Markers in Red |
No comments:
Post a Comment