Thanks for the large and quick response to my query about whether
surveyed distances and areas are measured as through they were
flat. The answer seems to be unanimous and worldwide. Contrary to
what they teach in schools these days, legally, the world is
flat. At least this is so in the US, Canada, Australia, Sweden,
and Denmark. Thanks to Peter Graham, Richard Greenwood, Mats
Elfstr�m, Andrew Young, Fred Limbach, Doug Pease, Roy Summers,
Steve Smith, Ole Gregor and Marlow for filling me in.
Richard Greenwood noted that this flat projection is actually
tied to the ellipsiod, which is a factor in parcel size:
> "In the US, real property distances and areas are calculated with Cartesian math
>(ie, right angle trigonometry) on a plane at an average surface elevation. I live
>about 6000 feet above sea level, so the area of a parcel in my neighborhood is about
>0.03% larger than it is when projected onto the ellipsoid (sea level)."
He also added some insight into why surveyors tend to use local
coordinate systems instead of standard smaller-scale map
projections:
> "Even using Cartesian math will produce minor differences when calculating distances
>and areas on a projected coordinate system versus a "local" coordinate system,
>because of the above sited difference is surface elevation, and because of the map
>scale factor, which is a function of the distance from the central meridian."
So it is true that you get more surface area for your money when
you buy land on a slope, but as Mats points out that's not always
a better buy:
> "... But the house you build will not get bigger unless you make the floors sloping
>as well.
> "The same principle applies in farming, a sloping field will not give a better yield
>because plants grow straight up, thus using the same space as on a flat field."
Andrew Young noted that construction costs are higher on slopes
too. Marlow's observation probably sums up this opinion best:
> "Buy flat land it is the best for everything"
Yet I think if you are measuring something like snow pack, forest
floor fuel, or similar things that are proportional to surface
area but using the flat-plane acreage, you might have to make
some adjustments to account for slope.
Thanks again, everyone!
- Bill Thoen
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