Unless a map neatline is square, one of landscape or portrait orientation will allow a feature or set of features to be displayed at a larger scale. For instance, if the feature is wider than it is high, a landscape orientation will allow it to be shown larger. If the map is part of a series made with ArcGIS Data Driven Pages, one .mxd can be prepared to produce the landscape maps and another to produce the portrait maps. (The benefit of larger scale comes with the sacrifice of inconsistency of the overall pages.)
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Note: this methodology only works perfectly if the .mxd files have identical (except for orientation) neat lines. It will work quite well if they are similar, but if they are quite different, the smaller dimension of one neatline may be larger than the larger dimension of hte other neatline.
Use the Feature Vertices To Points tool within ArcToolbox or if you do not have Advanced license then you may use the Polygon to Point tool from ET Geowizard (free tool). Finally, in ArcMap use the Add XY Coordinates tool to generate the XY value for each vertex and use Table to Excel to generate a spreadsheet.
- project the shapefile
- convert polygons to points
- export to spreadsheet
- establish deltaX and deltaY (maxifs)
- establish optimum orientation (if...)
- definition queries