Create Pseudo Drilling Spacing Units - Polygon inside another polygon from its boundaries

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12-05-2017 12:06 PM
coleblair
New Contributor III

I am trying to create pseudo Drilling Spacing Units. That corresponded with the section, township and range that they are generated from.

I am working with Sections from the Land grid in Oklahoma; Section Township and Range.

I need to generate a new polygon inside each section, with specific distances from the section boundary that it is generated inside of. The new polygon needs to be parallel with the boundary line and 165' from the north line, 165' from the south line, 330' from the west line and 330' from the east line.

This is ruffly what one new DSU (Drilling Spacing Unit) would look like Full Township with a Single Drilling Spacing Unit in Section 8

This is a schematic for what dimensions and the boundaries that are generated from. Section with Specific Dimensions generated from the polygons boundaries

The finished product would auto-generate the polygons like so??? The finished product with auto-generated polygons

I have used the buffer tool to create a polygon from the midpoint, however the boundary's that the new polygon draws from will change as you move across townships / ranges. so i need to go off each sections unique boundary.

I have been reading and searching so i apologize if this has been covered. however i have not found anything yet. I would appreciate your help, thanks.

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7 Replies
DanPatterson_Retired
MVP Emeritus

Generate a shape from a 'centre' and a displacement, then move the centre sequentially in the X and Y direction generating the bounding box coordinates as you go... here is a simple workflow explicitly shown for detail

Xc, Yc = 10, 10   # center coordinate

dx, dy = 4, 3.5   # delta x, delta y

L, B = (Xc - dx, Yc - dy)   # ---- get the left and bottom coordinate

R, T = (Xc + dx, Yc + dy)   # ---- get the right and top coordinate

LB = (L, B)  # ---- generate the 'box' coordinates

LT = (L, T)

RT = (R, T)

RB = (R, B)

LB, LT, RT, RB

((6, 6.5), (6, 13.5), (14, 13.5), (14, 6.5))

# --- to form a polygon, add LB to the end of the list
# --- now 'move the centre by the centre spacing you need and regenerate
coleblair
New Contributor III

Dan could you clarify
- Is this just a workflow, i don't understand if you are suggesting if i just use toolbox tools, a script or the model builder?

Thanks

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DanPatterson_Retired
MVP Emeritus

Oh sorry... It was a generic workflow for a script.  It would have been dead easy if your offsets from the outer polygon were equal since it would have just been a negative buffer.  I figured by the time you would have had to fiddle getting the differential offsets, it would have just been quicker to generate a rectangle that fit within the polygon, then replicate it in all the others.

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coleblair
New Contributor III

Ok i believe i understand now. I get the workflow of the script, but i have never attempted to script anything.

- If i have a end of the year deadline do you think it would be easy to figure out or maybe just do something with model builder? I realize this is very broad and opinion based question.

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DanPatterson_Retired
MVP Emeritus

No, modelbuilder only allows you to use scripts and tools that exist in arctoolbox.  Your 'slow spot' is the unequal offset which will require a script of some form

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coleblair
New Contributor III

I know there are endless resources for scripting. however do you have a suggestions for a jump off point?

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AbdullahAnter
Occasional Contributor III

There is another solution.If you have an advanced license.

First make the section boundary as polygon. And make the sub-boundaries as lines. you can use Feature To Line and  Feature To Polygon (both Available with Advanced license)

then Select vertical lines and create 330 feet buffer . and select the horizontal lines and create 165 feet buffer . Then Merge  the two input to one feature class.

Finally use Erase  tool to get your polygon features . make the major section boundary as input feature and the output of merge tool as erase feature.

I hope that be helpful.

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