The technique in outline
Astrocartography is a birth chart drawn as a world map. Hold the birth moment fixed, then move the observer. Every location from which Uranus would have been rising, setting, culminating or at the lowest point contributes to one of four lines running across the globe.
Jim Lewis developed the method in the 1970s. It is a modern technique and depends on machine computation, which is why it appeared when it did rather than centuries earlier. The older idea it rests on is angularity: a planet on one of the four angles of a chart is treated as emphasised. Uranus itself was only discovered in 1781, so its readings are modern on both counts.
Slow motion, and what still moves
Because Uranus moves so slowly, its zodiacal position is nearly the same for everyone born in a given week. The lines are not the same, though, because the map depends on where the sky was turned to at your birth moment. The Earth rotates once a day, so the entire set of lines sweeps around the globe over twenty four hours. Birth time, not birth date, is what places them.
The MC line follows the longitudes where Uranus was culminating on the meridian overhead, and the IC line where it was on the meridian below. Both are straight, since meridians are fixed circles through the poles. The AC and DC lines mark rising and setting, and these curve, because the horizon meets the ecliptic at an angle that varies with latitude. At high latitudes those curves distort sharply. All four lines are usually drawn as if identical in kind, which they are not.
What Uranus lines are read for
Uranus is read as disruption, independence, sudden change, technology and refusal to be arranged by anyone else. The MC line is described as a career that does not follow a normal shape, work involving invention or reform, and a public position that is unstable by nature. The difficulty named is a lack of continuity, changing course before anything settles.
The IC line is read as an unsettled home, frequent moves, and unconventional domestic arrangements. The AC line is described as being met as unusual or difficult to place, with abruptness and restlessness as the cautions attached. The DC line reads through others, associated with unpredictable partners and with connections that begin and end suddenly.
These are readings. They describe what a symbolic tradition attaches to a planet, and they say nothing about what a place will do to anyone who lives there.
Orb and the boundary of the claim
A line is conventionally read as active within a few hundred kilometres, most often stated as seven hundred to eight hundred, strongest on the line and weakening from there. The number is a convention of the literature. It was not measured, and there is no accepted way it could be, so practitioners vary it freely.
Astrocartography is geometry applied to a symbolic system, and the two parts should be judged differently. The geometry is exact and computable, which is why lines can be drawn precisely and why two programs given the same birth data produce the same map. What a Uranus line means where it crosses a city is convention. It is a way of framing a place, not advice to move to one.
Parans, where two planets are angular at the same latitude, and the relocated chart, which rearranges the houses for a chosen city, complete the toolkit.
Questions people ask about this
Why do people born the same week share Uranus positions but not Uranus lines?
Uranus moves slowly through the zodiac, so its degree barely changes. The lines depend on the Earth's rotation at the birth moment, so a difference of hours moves them right around the globe.
Does an accurate birth time matter for Uranus lines?
Yes, as much as for any planet. The whole set of lines shifts about fifteen degrees of longitude per hour, so an uncertain time makes the map unreliable regardless of how slow the planet is.
What does the Uranus IC line mean?
It is read as an unsettled home life, frequent relocation and unconventional domestic arrangements. That is a traditional reading of the symbolism, not a forecast.
Why do the rising and setting lines curve?
They track the horizon, whose angle to the ecliptic depends on latitude. That makes the rising point move as you travel north or south, so the line curves and can bend hard at high latitudes.
How far does a Uranus line extend?
Around seven hundred to eight hundred kilometres each side is the usual figure, strongest on the line. It is a convention rather than a measured range.
Is astrocartography a traditional method?
No. Jim Lewis developed it in the 1970s. Uranus was not even known to astrology before 1781, so nothing about this page draws on ancient sources.