[x_plus_one]

Is the north by northwest orientation due to magnetic pole location?

[muawiyah]

Depending on your latitude you can orient a building to MAXIMIZE SOLAR GAIN or MINIMIZE SOLAR GAIN. You can simplify the job by orienting your primary roadways so that all the houses are optimally placed.

A smart designer also takes a look at prevailing winds, average number of days it's below freezing, average number when it rains, the percentage overcast, and so forth.

The Spanish and others living on the West Coast of Europe figured out some rules of thumb to make the job even easier for town planners. The Chinese incorporated very similar rules in their Feng Shui.

The handful of attempts at laying out principal meridians I've found aren't all that long ~ few hundred miles. They also occur in the parts of the US that we know were the earliest to be penetrated by the Spanish. It's like they were started by folks unaware of how much deviation there was to magnetic North in North America.