Astrocartography Lines, Explained
An astrocartography map draws 40 lines across the globe: for each of ten planets, the places where it was rising, setting, culminating or at its lowest point at the moment of birth. This guide explains what each line is, how it is calculated, and how astrologers read it.
What a line is
A birth chart is drawn for one place. Its four angles, the Ascendant rising in the east, the Descendant setting in the west, the Midheaven at the top and the IC at the bottom, depend on where you were, because the sky turns over different places differently. Change the place but keep the moment, and the angles change while the planets stay put. An astrocartography line joins every place where one planet sat exactly on one angle. Ten planets on four angles make 40 lines.
The technique took off in the 1970s with Jim Lewis, who mailed hand-drawn Astro*Carto*Graphy maps to clients from 1976. The maps on this site are computed from the Swiss Ephemeris and are zodiacal: each line puts the planet's degree of the zodiac on the angle and ignores how far the planet sits north or south of the ecliptic, which makes the lines match a relocated chart. The form Lewis popularized is usually described as in mundo, drawn from the planets' true positions; for most planets the difference is small, and for Pluto, whose orbit is tilted 17° to the ecliptic, it can be hundreds of kilometers.
Two facts follow from the geometry. MC and IC lines run straight north and south, because the Midheaven does not depend on latitude; ASC and DSC lines curve. And every line moves together when the birth time changes, about one degree of longitude for each four minutes, so the map is only as precise as the time on the birth record. The lines are drawn from 66°S to 66°N, just inside the polar circles.
How this guide is organized
Each line has two parts, a planet and an angle, so the guide can be read either way, and two further sets of pages put lines together.
- The four angle pages compare the ten planets on one angle: what the MC does to each planet, and how the lines of that angle look on a map.
- The ten planet pages follow one planet across its four lines, with where those lines ran on a real chart.
- The four goal pages set out which lines astrologers read for love, career, money and health, and why, with their caveats.
- The crossings and parans page covers the places where two lines meet and the latitude bands that run through them.
- The map draws your own lines, and the Learn article walks through reading them one step at a time.
The four angles
The angle decides what a line is about. The two meridian angles are opposite each other, 180° of longitude apart, and so are the two horizon angles.
Where the planet's degree was culminating. A meridian, read for work, standing and reputation.
Where it was at the lowest point, opposite the MC. A meridian, read for home, family and roots.
Where it was rising. A curve, read for you: your manner, energy and body.
Where it was setting. A curve, read for partners and the people you deal with.
The ten planetary lines
The slow outer planets stay in one sign for years, so people born in the same week share their degrees; their lines still differ, because lines depend on the time of day. Pluto sat in Libra for everyone born in 1982.
Personal planets: the Sun, the Moon, Mercury, Venus and Mars
Sun Line
Moon Line
Mercury Line
Venus Line
Mars Line
Social planets: Jupiter and Saturn
Generational planets: Uranus, Neptune and Pluto
Uranus Line
Neptune Line
Pluto Line
Lines for a goal
No line means the same for every aim. These pages give the reasoning: which angle and planet each goal turns on, what readers warn about, and a worked example.
love
career
money
health
Crossings and parans
A crossing is where one planet's MC or IC line meets another's ASC or DSC line; a paran is the band of latitude through it, where the two planets reach those angles together at some hour of the day. Prince William's map has 74 crossings, and the crossings page explains how they are found and read.
Crossings and paransOne map, used throughout
The map page, the goal pages and the Learn article all work through Prince William's map, from the time in the official announcement of his birth (9:03 PM, June 21, 1982, London). Three of his lines pass close to his birthplace: Neptune ASC at 116 km, Jupiter MC at 130 km and Sun DSC at 157 km. The planet and angle pages each work through a chart of their own. Open William's map.
Every figure in the examples comes from the same calculation the map runs, regenerated whenever it changes, and is checked against the Swiss Ephemeris directly: on William's map the line points agree with its house routine within 0.39′.
Where to start
- Draw your map with an exact birth time, and pin the places you live in or are considering.
- Note which lines pass within a few hundred kilometers of each, and on which angle.
- Read the angle page for each angle you found, then the planet page for each planet.
- If you have a particular aim, read its goal page for the reasoning readers use.
- Check the crossings and parans near your places last; they combine readings you already have.
The astrocartography map
How to read your map
Questions about astrocartography lines
What is the difference between astrocartography and a relocated chart?
They are two views of the same calculation. A relocated chart recasts the birth moment for one city and shows its Ascendant, Midheaven and houses there. An astrocartography map shows the whole globe at once and draws only the places where a planet sits exactly on one of the four angles. Hovering over a city on the map gives its relocated Ascendant and Midheaven, so you can move between the two.
Is astrocartography the same as Astro*Carto*Graphy?
Astro*Carto*Graphy was Jim Lewis's name for the technique, which he sold as hand-drawn maps from 1976; the trademark lapsed in 2011. Astrocartography is now the general name, and software draws the maps in slightly different ways. This site draws zodiacal lines; the form Lewis popularized is usually described as in mundo, from the planets' true positions.
Can two people have the same map?
Yes, if they were born at the same instant, wherever on Earth that was. The lines depend only on the moment of birth in universal time. Twins born twenty minutes apart, on the other hand, have maps about five degrees of longitude apart.
Do I need to know my birth time?
Yes. Without a time there is no map, and an approximate time gives an approximate map: every line moves about a degree of longitude for each four minutes of error. On London's parallel a quarter of an hour is 260 km.
Are some lines good and others bad?
Readers do not divide them that simply. Each line is read for what the planet does on that angle, and the same line suits one aim and works against another: a Saturn MC line is read as slow going for a quick career but solid for a long one. The goal pages explain the reasoning for love, career, money and health.