# Symbolizing neighboring polygons in ArcGIS

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#1
Posted 27 October 2006 - 10:00 AM

Thanks for your help!

-Jesse

*Maps.com*

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#2
Posted 27 October 2006 - 11:02 AM

I am using ArcGIS 9x with ArcView license. I want to symbolize all the county polygons in a state with 4 colors so that no 2 colors touch. Is there a scipt that I can use to achieve this, or is there a way to even do this through the standard symbology interface?

Thanks for your help!

-Jesse

Jesse,

Have you checked ESRI's support site? I haven't looked there myself, as I don't normally have a need to do what you're doing in ArcGIS. But it's worth a look to see if something is there.

Your problem was a classic challenge in my intro carto class. Trying to find a way to color things so no two things colors touched. It's actually a fun exercise to do, if you have the time to do it. But, I understand your need to get something done as quick as possible.

Report back if you find anything.

GIS Manager

United States Marine Corps

West Coast Installations

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#3
Posted 27 October 2006 - 11:22 AM

I am using ArcGIS 9x with ArcView license. I want to symbolize all the county polygons in a state with 4 colors so that no 2 colors touch. Is there a scipt that I can use to achieve this, or is there a way to even do this through the standard symbology interface?

Thanks for your help!

-Jesse

If your need is to accomplish the end result, just do it by hand, it will be much easier than finding a script or writing one yourself. You can easily find an example map online, for instance, here: http://arcdata.esri....er_download.cfm

That's 5 colors BTW. Maybe that means its impossible with 4 colors - is there any state that has 4 neighbors?

[EDIT: Sorry I misread the question - you are talking about counties, not states. But I guess my question is still appropriate - is there any county that has more than 3 neighbors? If so, you won't be able to use a 4 color scheme]

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#4
Posted 27 October 2006 - 11:50 AM

p.s. Got this info from a colleague: if you have access to ESRI's Developer Network (EDN) there is sample code called "Four Color Map" for doing this in ArcGIS 9.x. This also sets up a field in the data's table that you can then use to symbolize with unique values.

Esri

Product Engineer

Map Geek

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#5
Posted 27 October 2006 - 02:28 PM

http://www.manifold....d_gis_users.htm

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#6
Posted 27 October 2006 - 08:07 PM

http://72.14.205.104...lient=firefox-a

""

It turns out that the best definition is that two regions are adjacent if they touch along a border rather than at a single point, or even a finite number of individual points. So in the ?Four Corners? region of the U.S., Arizona and Colorado aren?t considered neighbors ? they could share a color.

Now for the miracle: four colors are always enough! Any map you can possibly create in 2 dimensions can be colored with at most 4 colors (provided, of course, we agree on the rules about boundaries). You can color

hundreds of maps to convince yourself this is true, but in math we would like to convince ourselves and each other about things like this in a more straightforward way. In other words, we want to prove it. But here?s a shock: our simple problem and simple answer took nearly 150 years to prove, with the best mathematicians trying hard all that time! Even now, the proof is complicated and requires a computer ? not so nice and neat as

mathematicians would like. The proof is not easy to understand, but you might enjoy looking at it anyway. There are some great references on the Internet, some of them by the mathematicians who came up with the latest proof. For a good discussion and some useful links, try http://www.math.gate.../fourcolor.html. You can also get a nice historical account of the development of this problem and its solution in the book Mathematics Today edited by Lynn Arthur Steen.

""

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#7
Posted 28 October 2006 - 01:33 PM

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#8
Posted 28 October 2006 - 03:30 PM

Wick - Let us know what solution you end up using.

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#9
Posted 26 April 2007 - 05:02 PM

Wick - Let us know what solution you end up using.

Sorry it's been a long time since I originally posted this.

My goal was to assign color values to each of the counties in the USA with a 1,2,3 or 4.

I first found the "Four Color Map" developer sample from ESRI. http://edndoc.esri.c...ourColorMap.htm

This works, but it was extremely slow to process even 1 state at a time (and I wanted them all!).

I ended up doing a few states manually before later finding "For Color a Map" (note the subtle name difference) on the ESRI forums. http://arcscripts.es....asp?dbid=14822

With this I installed a toolbox containing a simple tool that allowed be to

*fly*through the entire USA counties dataset in seconds! The only work left to do was update the number value for island counties, as those were not given a 1,2,3 or 4.

Hope this helps.

*Maps.com*

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#10
Posted 06 September 2008 - 01:19 PM

Wick - Let us know what solution you end up using.

Sorry it's been a long time since I originally posted this.

My goal was to assign color values to each of the counties in the USA with a 1,2,3 or 4.

I first found the "Four Color Map" developer sample from ESRI. http://edndoc.esri.c...ourColorMap.htm

This works, but it was extremely slow to process even 1 state at a time (and I wanted them all!).

I ended up doing a few states manually before later finding "For Color a Map" (note the subtle name difference) on the ESRI forums. http://arcscripts.es....asp?dbid=14822

With this I installed a toolbox containing a simple tool that allowed be toflythrough the entire USA counties dataset in seconds! The only work left to do was update the number value for island counties, as those were not given a 1,2,3 or 4.

Hope this helps.

Hi!!!

I was surfing for a script to color my polygons, and saw this thread quite interesting.But i deed everything that the readme txt file said and to everthing written and said things to color my polygons, but everything was invain. can somebody suggest me any better script than this one which is easier to use. Or else will someone give me a step by step process to install this script, which includes dll registry to final coloring please. Coz i don't know what am i missing.

any help will be appreciated.

Thanks

GISGURU

Thanks and Regards

Kalai Selvan

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