# How to split a polygon into quadrants?

I have a Alberta province (Canada) section polygon shapefile in GCS_NAD83 with 255,000 polygons. I like to split each section into 4 equal quadrants (NW, NE, SW, SE)

The Alberta province has several UTM zones, so I guess I can convert it to Lambert Conformal Conic or Albers Equal Area CS if the section scan be split only in projected units. There are people selling this information, but I was wondering if this is something I can create using the data I have? Please let me know. Thank you.

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Do you need to take road allowances into account? – Kirk Kuykendall Nov 30 '12 at 17:25

## 6 Answers

I've created 4 tools which might help you out.

1) The first 2 tools create a quarter section grid from an existing section grid and provide custom labeling for each quarter section.

2) The other 2 tools create a quarter quarter section grid from an existing section grid and provide custom labeling for each quarter quarter section.

I say from an existing section grid, but it will work with any polygon grid.

You can view a video (which needs updated) and download the Section Grid Toolbox here:

http://ianbroad.com/creating-quarter-quarter-section-grid-python/

I hope this helps in some way.

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I did something similar with a grid system we use, but I did it all with math and excel. You just need one anchor point and create the corners and then import them into ArcGIS. Granted I had GEOROVER to create my 275,000 polygons, but I used 3 excel formulas to generate all my points. With some creative labeling, I was able to create my grid.

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We're looking for long answers that provide some explanation and context. Don't just give a one-line answer; explain why your answer is right, ideally with citations. Answers that don't include explanations may be removed.

Can you elaborate a bit more a bit your process? Maybe edit your answer to include the Excel formulas so that others may benefit from the answer. – Fezter Dec 11 '12 at 22:38
1. create fishnet using create fishnet in ArcMap .enter the x and y coordinate . cell size width and cell size height .
2. split your polygon using result of fishnet.
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To divide each township polygon into 4 equal-sized quadrants, you can iterate through each polygon and apply the Create Fishnet tool and set both the number_rows and number_columns parameters to 2. You can try applying the Create Fishnet tool to the extent of your polygon shapefile, using dimensions that approximate quarter sections, but the boundary locations will not be accurate (especially if you have the township polygon that has the road allowances and offsets). Therefore, each township polygon must be processed independently - ModelBuilder or Python will help to automate this.

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What you are describing is the Alberta Township System (ATS), which is a variation of the Canadian Dominion Land Survey (DLS) system. We in the US have an old system like these called the Public Land Survey System (PLSS). I've found three potential sources of information for you:

1. The best option to create this grid would be to do it your self using Layers > Properties > Grids following this description.
2. Free small scale data is available here.
3. Finally, there is a pay option.
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The free small scale data (#2) will require downloading and merging all 1:250k tiles, and then figuring out which layer values correspond to the quarter section boundaries. However, there are no attributes to make this an easy task. – ccn Nov 30 '12 at 16:59
#2 may be useful to compare a homemade grid with an official Alberta grid, or to reference small areas. – Aaron Nov 30 '12 at 17:07

SAGA-GIS has a module: Shapes > Construction > Split shapes layer . This can do what you want i believe.

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