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• This should reveal the internal boundary lines.  (External boundary lines are deselected because they border the outside of the country and received a 'NULL' left polygon identifyier.  THIS WORDING CAN BE IMPROVED.)
• Open the output polyline shapefile attribute table
• Use the Field Calculator to calculate all the LEFT_Ax values (for the LEFT_Ax fileds recently added to the polyline shapefile ) equal to the coresponding administrative levels of the polygon shapefile.

• the LEFT_A2 = adm2code, that is, each LEFT_A2 value will be made equal to the adm2code of the joined input polygon shapefile feature.

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• Close the attribute table, remove the join, and establish a new join basing on RIGHT_FID.  Anticipate all records matching.
• This time there should be no need to make a definition query, as there should be no null values.
• Open the output polyline shapefile attribute table.
• Use the Field Calculator to calculate all the RIGHT_A2 = adm2code, RIGHT_A1 = adm1code, and RIGHT_A0 = adm0codeAx values (for the RIGHT_Ax fileds recently added to the polyline shapefile ) equal to the coresponding administrative levels of the polygon shapefile.
• Create a definition query to select the line segments with different LEFT_A0 and RIGHT_A0 attributes.

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  Administrative levels in boundary polygon shapefile	Required calculations
  Administrative level 0
  Administrative levels 0 and 1	polyline shapefile RIGHT_A0 = polygon shapefile Adm0code polyline shapefile RIGHT_A1 = polygon shapefile Adm1code
  Administrative levels 0, 1, and 2	polyline shapefile RIGHT_A0 = polygon shapefile Adm0code polyline shapefile RIGHT_A1 = polygon shapefile Adm1code polyline shapefile RIGHT_A2 = polygon shapefile Adm2code
  Administrative levels 0, 1, 2, and 3	polyline shapefile RIGHT_A0 = polygon shapefile Adm0code polyline shapefile RIGHT_A1 = polygon shapefile Adm1code polyline shapefile RIGHT_A2 = polygon shapefile Adm2code polyline shapefile RIGHT_A3 = polygon shapefile Adm3code

  
  

[IF THIS DOES NOT WORK, ENTER ' "LEFT_A0" IS NULL']

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