Astrocartography
Astrocartography overlays your birth chart onto a map of the world: lines on the globe show the places where each planet would have been on an angle at the moment you were born. The method was introduced by Jim Lewis in the 1970s.
How It's Built
Four lines are drawn for each planet: where it would have been on the Ascendant, Descendant, MC, and IC at the moment of birth.
Sun, Venus, and Jupiter lines are considered favorable, and places along them are recommended for relocation, vacations, or work. Saturn, Mars, Neptune, and Pluto lines are considered difficult.
The interpretation is simple: near a planet's line, that planet's theme in your life gets stronger. The Venus line means relationships and pleasure, the Saturn line means hard work and limitations, the Sun MC line means career.
How People Use It
Choosing a city to move to, a vacation destination, or a place to work. There is also a separate practice called the "local chart" (relocated chart): recalculating the birth chart for new coordinates, which produces different houses with the same planets.
Keep the scale in mind: the lines run across entire continents, and a "Jupiter line" can cover half a country. The precision here is inherently low.
Why We Don't Have a Calculator
Computing the lines is not algorithmically difficult, but the result is a world map, not a number, and it is useless without visualization. A full interactive world map with lines would be a separate project.
Besides, the practical value of such a calculation is close to zero: people decide to move based on work, language, climate, visas, and loved ones, not a line on a map.
An Honest Look at the Method
Astrocartography is the youngest method in this section: it is about half a century old. It has never been tested at all, and its internal logic raises questions even among astrologers: why should a planet's position relative to the horizon at a place a person has never been affect their life there?
The only case where we would take notice: if astrocartography is used as a reason to turn down a necessary move or, conversely, to spend money on a distant "favorable" city. Then it's worth stopping to think about the real grounds for the decision.