Astrocartography is a branch of locational astrology that maps the angular positions of the natal planets across the surface of the Earth, drawing lines for the places where each planet was on the Ascendant (ASC), Descendant (DSC), Midheaven (MC) or Imum Coeli (IC) at the moment of birth. By relocating the chart to any city on the globe, astrocartography reveals where the natal planets become angular and therefore most active in shaping experience. The technique was developed in its modern form by Jim Lewis in the 1970s, who coined the term "Astro*Carto*Graphy" and produced the first commercially distributed maps in 1976.

An MC line is the meridian where a planet was culminating at the moment of birth and tends to bring that planet's themes into career, public reputation and outer life. An IC line is the opposite meridian, associated with home, family roots, inner foundations and ancestral material. An ASC line marks the longitude where the planet was rising, projecting the planet's quality onto self-presentation and physical experience, while a DSC line marks where it was setting, channeling the planet through partnerships and significant others. Living, traveling or even strongly thinking about a place near such a line activates that planetary archetype in a personal way.

Parans, short for the Greek paranatellonta ("rising together"), are latitudes at which two planets are simultaneously angular - one rising, setting, culminating or anti-culminating while the other is angular as well. Unlike the great-circle planetary lines, parans run as horizontal latitude lines across the map and influence every longitude at that latitude. Bernadette Brady, building on Hellenistic and Egyptian sources, popularized paran analysis in modern astrocartography, showing that paran latitudes carry an interaction between two planets felt as a constant background hum in any city at that latitude.

Astrocartography uses the celestial sphere and the four angles to project planetary lines onto a world map, treating each line as a global meridian or great circle. Local space astrology, developed by Michael Erlewine in the 1970s, casts azimuthal lines from a specific location on Earth in the directions of each planet at the moment of birth, producing a personal compass-like map centered on the chosen point. The two systems answer related but distinct questions: astrocartography asks "where on Earth is each planet angular for me?" while local space asks "in what direction does each planet pull from where I am right now?".

Astrocartography is one of the most time-sensitive techniques in astrology because the entire map shifts roughly one degree of longitude (about 111 kilometers at the equator) for every four minutes of clock time. A birth time that is off by even fifteen minutes can shift planetary lines by a thousand kilometers or more, potentially placing a Mars line on the wrong side of a country. For meaningful astrocartographic interpretation a birth time accurate to the minute is strongly recommended; if the time is uncertain, rectification through known biographical events or the comparison of multiple proposed times is advisable before drawing relocation conclusions.