MapForums

Hi everybody,

I have 2 drive time zones A and B with a common area C.
A is blue
B is yellow

If B comes after A, the color of the intersection C between A and B is yellow.

If A comes after B, the color of the intersection C between A and B is blue.

I want the color of C to be different , Red for instance.

Is there a solution with Mappoint?

I can do that with other GIS.

Thanks in advance.

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Mohamed
www.AtlasCouscous.com

Hi Mohamed,

This is not so easy with MapPoint but possible with programming. One way you might approach it is to export the polygons to another GIS, do your cookie cutter stuff and prepare three polygons, and then re-import them into MapPoint using the Spatial Data Importer.

They can be exported using something like Walt Cygan's mif/mid exporter --
http://www.mp2kmag.com/importersub01.asp

hope this helps.
Eric

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Thanks Eric,

I do my drive time zones by programmation in Mappoint. But I don't know how to fill the intersection with another color. I am using other GIS like GeoConcept, Map&Guide, MapInfo for some complementary tasks. But I want my Mappoint Application to be independant V/s other GIS.

Thanks again for the help.

__________________
Mohamed
www.AtlasCouscous.com

I think you'd have to figure out how to do the polygon operations in your own code, math stuff. Perhaps there's a lightweight library or control you can take advantage of... ?

Eric

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I don't know of any libraries - there could well be some, and they would make it easier.

The individual components in geometry calculations like this aren't too complicated, but there are often various special cases that will trip you up - eg. coincident points and lines.

For this one, you will need a "point in polygon" algorithm. For a past employer, I coded one from Sedgwick's "Algorithms".
This projected a line from the point to infinity, and counted the intersections with polygon edges. Odd = Inside the polygon; Even = Outside.
Your projected line should be horizontal or vertical to simplify the maths.


You will also need to check for intersections between two lines. I think I found something in the Graphics Gems series in the past. I can't remember the details now but it might have involved a vector product of somekind.

Richard

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Winwaed Software Technology LLC
http://www.winwaed.com
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Hi,

The solution I've found now is to color directly by programming the GIF
generated by HTML saving. I hope I will find a best solution in the future.
The intersection between two drive time zones is very important for
a lot of marketing subjects. For instance this area is a " cannibalization area"
for two stores. The costumors found in that area are very coveted by the two stores.

Thanks for your suggestions anyway.

__________________
Mohamed
www.AtlasCouscous.com