The map makers for the LCA aren't very sharp. As they are relying almost totally on the General Assembly's GIS office, they are forced to buy into their way of doing things. Unfortunately, these folks are set up primarily for demographic and financial analysis, and are not interested in getting into the gritty details of property lines and natural features. The power of the GIS system is all the data that can be mined simply by drawing a few lines on the map program, resulting in fairly accurate demographic information - population, racial and ethnic distribution, income, party affiliation - all those things of most interest to a politician. And this GIS program is based on the federally defined Census Blocks.
ETA: Ahhh. Now I understand. I was informed tonight that Millar's border for Lakeside, reaching so deeply into the Livsey Elementary School district, was specifically designed to make sure a personal friend of his, a homeowner in the area, would be included within Lakeside. So disappointing that a politician would use such a personal and shallow relationship as his main reason for continuing to abuse the Tucker community. But then, as we all know, that's St. Francis of Dunwoody's style. Man, what an asshole. (And 'NO' Ms. Caroline, its not you.)
The area as represented in a Google Maps Terrain View, illustrating surface features including hills and creeks.