I am going to answer my own question here. I found I can get the coordinates buried in the maplineshape (or any other geospatial table object, I think) in the following way:
T = readgeotable("concord_roads.shp");
T2=geotable2table(T,["X","Y"]);
x=T2.X;
y=T2.Y;
There is probably a better way to do this, but it works. The documentation for geotable2table doesn't say anything about getting coordinates out of a geospatial table object so I was just trying stuff.
