[MWForum]Calling mathcats: geometry help please
Jeff Knope
mwforum@lists.mathcats.com
Thu, 12 Aug 2004 03:50:16 -0700
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Wendy,
That's brilliant!=20
It drove me nuts for a half-hour, trying to figure out what on earth you =
were doing. Most especially, how you were doing the writing to =
"intersection. I even wondered, "Why would she make the lines different =
colors?" It finally occurred to me to look in the Project Tab. Duh.
It's interesting to note your program yields somewhat different results =
in EX than in Pro. This is because Pro's towards truncates heading to a =
whole number, resulting in errors of up to one full degree. EX's towards =
preserves the decimal portion of heading.
I have a Pro utility procedure toward that makes it behave like EX. If =
anyone wants it, just say so.
I think you may well have solved my problem. Thank you. Still, if anyone =
has a mathmatical solution, I'd love to see that too.
--Jeff
----- Original Message -----=20
From: "Wendy Petti" <wpetti@mathcats.com>
To: <mwforum@lists.mathcats.com>
Sent: Wednesday, August 11, 2004 11:11 PM
Subject: RE: [MWForum]Calling mathcats: geometry help please
> I lack the programming and mathematical expertise needed to fully =
grasp let
> alone solve this problem, but I hope the attached project might be a =
step in
> the right direction. I'm not very good with list processing, so I =
placed
> the 4 inputs as 4 lines in a textbox. I leave it to one of you to =
adapt the
> code to the input format Jeff requests: [[[x1 y1][x2 y2]] [[x3 y3][x4 =
y4]]]
> and to wrestle with the question of how to find an intersection =
outside the
> specified line segments.
>=20
> But I will say that at least with this simple example of inputs, where =
the
> two line segments do intersect, I've managed to draw the two line =
segments
> and output their intersection.
>=20
> My humble project could not handle coordinates that exceed the limits =
of the
> project page. But it might be possible to use the basic concept of =
this
> project to extend line segments beyond their specified starting and =
ending
> points to determine if and where they intersect.
>=20
> Attached: intersection_of_lines.mw2
>=20
> Wendy
> OWL's MicroWorlds in Action
> http://mia.openworldlearning.org
>=20
>
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<DIV><FONT face=3DArial size=3D2>Wendy,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>That's brilliant! </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>It drove me nuts for a half-hour, =
trying to figure=20
out what on earth you were doing. Most especially, how you =
were doing=20
the writing to "intersection. I even wondered, "Why would she make=20
the lines different colors?" It finally occurred to me to look in =
the=20
Project Tab. Duh.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>It's interesting to note your program =
yields=20
somewhat different results in EX than in Pro. This is because=20
Pro's <STRONG>towards</STRONG> truncates heading to a whole =
number,=20
resulting in errors of up to one full degree. EX's=20
<STRONG>towards</STRONG> preserves the decimal portion of=20
heading.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I have a Pro utility procedure=20
<STRONG>toward</STRONG> that makes it behave like EX. If anyone wants =
it, just=20
say so.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>I think you may well have solved my =
problem. Thank=20
you. Still, if anyone has a mathmatical solution, I'd love to see that=20
too.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>--Jeff</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>----- Original Message ----- </FONT>
<DIV><FONT face=3DArial size=3D2>From: "Wendy Petti" <</FONT><A=20
href=3D"mailto:wpetti@mathcats.com"><FONT face=3DArial=20
size=3D2>wpetti@mathcats.com</FONT></A><FONT face=3DArial =
size=3D2>></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>To: <</FONT><A=20
href=3D"mailto:mwforum@lists.mathcats.com"><FONT face=3DArial=20
size=3D2>mwforum@lists.mathcats.com</FONT></A><FONT face=3DArial=20
size=3D2>></FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Sent: Wednesday, August 11, 2004 11:11=20
PM</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Subject: RE: [MWForum]Calling mathcats: =
geometry=20
help please</FONT></DIV></DIV>
<DIV><FONT face=3DArial><BR><FONT size=3D2></FONT></FONT></DIV><FONT =
face=3DArial=20
size=3D2>> I lack the programming and mathematical expertise needed =
to fully=20
grasp let<BR>> alone solve this problem, but I hope the attached =
project=20
might be a step in<BR>> the right direction. I'm not very good =
with=20
list processing, so I placed<BR>> the 4 inputs as 4 lines in a =
textbox. =20
I leave it to one of you to adapt the<BR>> code to the input format =
Jeff=20
requests: [[[x1 y1][x2 y2]] [[x3 y3][x4 y4]]]<BR>> and to =
wrestle with=20
the question of how to find an intersection outside the<BR>> =
specified line=20
segments.<BR>> <BR>> But I will say that at least with this simple =
example=20
of inputs, where the<BR>> two line segments do intersect, I've =
managed to=20
draw the two line segments<BR>> and output their =
intersection.<BR>>=20
<BR>> My humble project could not handle coordinates that exceed the =
limits=20
of the<BR>> project page. But it might be possible to use the =
basic=20
concept of this<BR>> project to extend line segments beyond their =
specified=20
starting and ending<BR>> points to determine if and where they=20
intersect.<BR>> <BR>> Attached: =
intersection_of_lines.mw2<BR>>=20
<BR>> Wendy<BR>> OWL's MicroWorlds in Action<BR>> </FONT><A=20
href=3D"http://mia.openworldlearning.org"><FONT face=3DArial=20
size=3D2>http://mia.openworldlearning.org</FONT></A><BR><FONT =
face=3DArial=20
size=3D2>> <BR>> </FONT></BODY></HTML>
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