Start with Geography

 Start with Geography: A layout design approach that begins with developing a realistic geographical plan, and then proceeds to the creation of a track plan to fit the geography, not vice versa.

Usage: Mary was in the first stage of designing her layout using the Start with Geography technique.

Source: Paul Garrison outlines the basic principles in his February 1975 Railroad Modeler article, Start with a River:

The fact is that many a layout, though beautifully constructed and landscaped, suffers from the lack of logic that results when the builder starts by designing the desired routing of his track and then superimposes the landscaping as little more than an afterthought. While it is admittedly impractical to start with the landscaping, a procedure that would make track laying difficult if not impossible, one might consider designing a piece of countryside with paper and pencil, and then find ways to adjust the routing of track to its topography.  

In the article Mr. Garrison walks the reader through the process using the design of his 2.5' x 15' N-scale layout based on the terrain near a portion of the upper Rio Grande river as an example.

Model Trains ran a series in the Dec '57, Jan '58, and Mar '58 issues where the authors, Andy Anderson and Katie McMullen, came close to doing just what Mr. Garrison advised against: they built the scenery first on their project layout the Hither, Thither & Yonder. More accurately, they did have a track plan from the outset of construction, so the scenery was built with placing the track in mind. They didn't hack out a right-of-way from the completed landscape, they just didn't install the track until the scenery was complete. However, it does appear from the track plan that it was designed first, and then the geography was designed to accommodate the route.

See also, Three Ws, Full Observation.

from The Dictionary of Non-Existent Model Railroad Terms, 2nd ed., 1999.