Comments on: The problem with America – spatial data

By: robfarley

robfarley — Sun, 07 Dec 2008 21:12:02 +0000

Kalman,

Yeah – pilots don’t have a problem with this stuff. They know that the map shows a straight line as curved. But when people see a line that’s straight on the map (like the US border), they often have trouble understanding that it’s actually a curved line.

Rob

By: Kalman Toth

Kalman Toth — Sun, 07 Dec 2008 08:30:00 +0000

Rob,

I do not get the concept of straight in map context since the Earth is spherical shape.

Even the Equator is not straight line, it is a circle.

If I fly from Boston to New York, I can really keep the plane flying straight with modern navigation, yet it is flying a curved path.

Do you mean the shadow of a straight line on the surface of the Earth as “straight”?

By: robfarley

robfarley — Sun, 16 Nov 2008 21:09:28 +0000

Yes, exactly. I bet there are many people who consider that the many state borders are straight, just because that’s how they’re shown on a map.

Do you think 400km is accurate enough? I suppose it depends on how accurate you need your points to be (like, how close things are to the border).

Rob

By: SoulSolutions

SoulSolutions — Sun, 16 Nov 2008 19:55:35 +0000

Its a case of SQL2008 be accurate compared with much of what we see on maps that assume the earth is flat.
If you were to convert the data to a geometry type this could provide a solution. Or else get a more accurate polygon with weighpoints every 400 KM.
John.