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1. Data Preparation and Creating a Polygrid

Data Preparation

First, click the AdvancedTutorialStart file to open up ArcMap. You will only need two shapefiles: a Site Boundary and a Land Use Layer. Here we will use the provided files: "Site_Boundary" and "LU_Layer"




 

"LU_Layer" needs two specific fields: a land use category (EX_LU) and a field for acreage (TOT_ACRE). The LAND_USE field can be anything that tells you whether or not a parcel is vacant or developed. If the land use layer does not have a TOT_ACRE (which ours does not), create it:

  1. Right-click on the shapefile name in the Table of Contents and choose Open Attribute Table.



  2. Click on the Table Options button and select Add Field. 
                
                              
           
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  3. In the Add Field Box, next to Name: enter "TOT_ACRE", next to Type: enter "Double". Click OK.



  4. Right-click on the column header for TOT_ACRE and select Calculate Geometry. You will receive a prompt about "...outside of an edit session", click "Yes".


  5. In the Calculate Geometry Box, ensure that Property: is set to "Area". Next to Units: select "Acres US [ac]", then click OK. You will be prompted about 'calculating outside of an edit session', just click 'Yes'.

Now we will create the Polygrid. Keep in mind you can also skip this next step and paint by parcels or existing features, but the polygrid allows for a much more nuanced analysis.


Polygrid


  1. Use the Buffer tool on the project boundary shapefile. At the top of the menu, select Geoprocessing and choose Buffer.  In the Buffer Box, under Input Features choose “Site_Boundary”, under Output Feature Class navigate to your working folder and enter the name of your output “Buffer_Boundary”, under Distance choose “Linear unit” and enter “250 feet”. Click OK.



  2. Clip the parcel layer to the newly created buffered boundary. At the top of the menu, select Geoprocessing and choose Clip.  In the Clip Box, under Input Feature choose "LU_Layer", under Clip Features choose "Buffer_Boundary", under Output Feature Class navigate to your working folder and enter the name of your output "Clipped_LU_Layer". Click OK.
  3. Next, using the method to add a field (as shown above with TOT_ACRE), add a new field called "MAX_SIZE" to your newly created Clipped_LU_Layer. Next to Type: enter "Float", and next to Precision enter "5" to keep the width of the field relatively small. Click OK. 
  4. Now we want to populate MAX_SIZE. At the top of the menu, select Selection and choose Select By Attributes...  
    In the Select By Attributes Box, next to Layer: choose "Clipped_LU_Layer", in the selection box type      "TOT_ACRE" > 1    . Click OK.  
    Right-click on Clipped_LU_Layer in the Table of Contents and Select Open Attribute Table. Click on the Show selected records button and then right-click on the column header for MAX_SIZE and select Field Calculator.





    In the Field Calculator Box, under MAX_SIZE = enter the number 1. Click OK. 



    Now click the Switch Selection button and enter the value for MAX_SIZE as 0. Click OK.



    Clear Selected features before you move on:



  5. Now, add MIPTools_V10 to your ArcToolbox (located in the 1_DataPrep folder). At the top of the menu, navigate to the ArcToolbox Button. 


    Right-click on ArcToolbox and select Add Toolbox. Then navigate to your downloaded Toolbox and click Open.


     

    The Toolbox should now be added to your collection of Toolboxes.
         


  6. Use the Polygon Splitter. Within the MIPTools_V10 Toolbox, double-click Polygon Splitter. Under Input Polygons: navigate to your Clipped_LU_Layer and click Add, under Split Field select "MAX_SIZE", and under Output Feature Class navigate to your working folder and enter the name of your output "Draft_Polygrid_Layer". Click OK.



  7. Clean up the Polygrid. When the splitting process is done (you may have to click "Close"), navigate to Selection at the menu header and choose Select By Location... 



  8. In the Select By Location Box, choose Draft_Polygrid_Layer as the Target layer and Site_Boundary as he Source layer. Under Spatial selection method for target layer feature(s) choose "have their centroid in the source layer feature". Click OK. 




  9. In the Table of Contents, right-click on Draft_Polygrid_Layer and select Data>Export Data. Navigate to your working folder and name it “Site_Polygrid”.




    Be sure to save as type: "Shapefile"  



    ...and you now have your working polygrid!


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