Re: Determining Distance between 2 points

From: "A. Jans-Beken" <jansb000@wxs.nl>

Date: Sun, 01 Oct 2000 00:00:00 +0000

In a grid the pythagorean formula does not work. This is because a grid does not
behave like the real (analog) world. The distance between two points in a grid can
be calculated like this:

POINT p1 = x1,y1;
POINT p2 = x2,y2;
DISTANCE d = max(abs(x2-x1),abs(y2-y1));

Andrea Ryan wrote:

> Your triangle is a right triangle with one angle of 90 degrees.  Triangles that
> have all sides of equal lengths are equilateral triangles and have three angles
> of 60 degrees each.
> Brendan
>
> Chris Williams wrote:
>
> > I'm calculating the distance for missle fire (arrows or rocks) and I have
> > one question.
> >
> > When I plot out two points on a grid, and then use Pythagorean Theorem to
> > calculate distance, I often come up with (at least) one square more than the
> > actual number of squares on the most direct path (based on my grid).
> >
> > Should I subtract one from my calculated results, or add 1 to the number of
> > squares?
> >
> > For Example:
> >
> > If I eyeball it on the grid, it's 5 squares from point a (top left) to point
> > b (bottom right).
> >
> > If I actually calculate it, it's 7.07. Of course we would round down to 7
> > squares, since we can't have a partial square.
> >
> > Any suggestions?
> >
> >   a=5
> > . . . . . . .          5^2 + 5^2 = d^2
> > .+- - -+.             25 + 25  = d^2
> > . . \ . . | .                       50 = d^2
> > . . . \ . | . b=5             7.07 = d
> > . . . . \ | .
> > . . . . .+.                          d = 7 (rounded)
> > . . . . . . .
> >
> > So my result is 7, but if you base it off the grid, d should equal 5.
> >
> > Any advice is appreciated.
> >
> > Chris Williams

References

Determining Distance between 2 points
"Chris Williams" <williac6@rjrt.com>
Mon, 11 Sep 2000 20:22:52 +0000
Re: Determining Distance between 2 points
Andrea Ryan <aryan@global2000.net>
Thu, 21 Sep 2000 00:00:00 +0000