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- Right-click the polyline shapefile > "Joins & Relates" > "Join..." (or properties > Joins & Relates) and provide the Join Data as follows:
- "What do you want to join to this layer?" = Join attributes from a table
- "Choose the field in this layer that the join will be based on:" = LEFT_FID
- "Choose the table to join to this layer, or load the table from disk:" = (the input polygon shapefile)
- "Choose the field in the table to base the join on:" = OBJECTID (or FID)
- Select "Keep only matching records". These will be the line features that are not boarding the sea or a neighboring country. If you do not do this, the field calculation stages described below may fail because un-joined records are included in the table.
- Optionally, click the ‘Validate Join’ button. Do not expect all records to match - because the ‘left’ side of all exterior lines will have no neighboring polygon. Do not worry if you receive a “Field names that match reserved words should not be used in database schema and can cause the join to fail. The following fields match reserved words….” message. Close the 'Join Validation' dialogue box after inspecting the result.
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