determine of a coordinate is in a quadrilatera 1

[kirkhettfield]

Hi

I have a problem ( i'm stuck for a few days now) My problem is that I must determine of a coordinate is in a quadrilateral.
To put it simple, I get a coordinate from my GPS and i want to know if I'm on my property.

Does anyone has an idea how to program this? I thought about it a lot and I don't see a simple solution.

Thanks in advance.

 

[jmeckley]

this is a math problem. Once you have the math the code is simple. You have a point X. you also have some information to define the area
as an examples:
triangle:
length of 2 sides and an angle
2 angles and the length of one side
square:
length of 1 side
rectangle:
height and width
circle:
something to do with radius or diameter
polygon:
a level of math I don't have

you would also have point(s) to define where the area is located. finally, ask the polygon if the point is contained within its area.

some design concepts I could see in play.
1. Point is an immutable value object.
2. Polygon would be an interface/abstract class for all shapes.
3. You may have specific shapes like rectangle, square, circle to simplify the math or be explict about the shape.
4. Polygon seems like a good candidate for the fly weight pattern (not that a pattern should be used "just because")
5. Polygon may also be an immutable value object.

I know these are very high level ideas, but it's the math that you and I are stuck on.

Jason Meckley
Programmer
Specialty Bakers, Inc.

 

[MichaelRed]

Get the lat / lon of the "corners" of the property. Check GPS lat lon to see if they re within the min/max of the porperty lat lon figures. If the property is 'mor-or-less' a rectangle, that should do it, otherwise delve deeper, but use the sam approach - just slice the property into smaller chunks until you have 'regular' figures (rectangles or perhaps triangles).




MichaelRed

 

[jmeckley]

great idea, break the area in simple, common shapes, rather than mess with calculus

Jason Meckley
Programmer
Specialty Bakers, Inc.

 

[MichaelRed]

yes, but then that is (at least one concept in) calculs ... generally used to calculate the area of irregular shapes




MichaelRed

 

[kirkhettfield]

Thank you guys, but i found a better solution.

If anyone is interested.

http://sites.google.com/site/abylexsite/Home/dotnet/determine-if-the-point-lies-inside-the-region

 

[jmeckley]

nice find. I think the naming convention an argument explosion is horrendous, but a little refactoring can fix that.

Jason Meckley
Programmer
Specialty Bakers, Inc.