How to read your map
Start with a lens, not a line. Pick what you care about right now (career, love, a trip, a place to settle) and the map colors only the lines that matter for it. Then look at how far a place sits from its line. Close counts: a city right on your Venus line reads differently from one 500 miles away. Every list shows the distance, so you can judge for yourself instead of trusting a color.
That is the whole idea of astrocartography: your birth chart, drawn onto the world. The lines don't change once they're drawn. What changes is which ones you pay attention to.
The four angles in one picture
At the moment you were born, every planet was overhead somewhere on Earth, underfoot somewhere else, and rising or setting along two long curves. Those are the four lines each planet draws: MC (overhead), IC (underfoot), ASC (rising in the east) and DSC (setting in the west). Ten planets times four angles makes the 40 lines on your globe.
Each angle has its own flavor. Overhead lines are about your public life and work. Underfoot lines are about home and roots. Rising lines color how you come across. Setting lines are about the people you meet. The planet sets the theme; the angle says where in your life it shows up.
Why lines bend near the poles
The overhead and underfoot lines are meridians: they run straight from pole to pole. The rising and setting lines are different. Each one is half of a great circle, and the two halves curve toward the poles and join the meridians up north and down south. On a flat map those curves look stretched and wild near the top. On a sphere they are one clean ring per planet, which is why we draw your map on a globe. It also explains why far-northern cities sit near many lines at once: the curves crowd together there.
Birth time and bands
Birth time matters more than anything else on this page. The Earth turns one degree every 4 minutes, so a 4-minute error moves every line about 70 miles east or west. If you know your time to the minute (a birth certificate is best), pick Exact. If you only know it within an hour, we draw each line as a band and rank places by averaging across that hour, marked approximate. With a rough guess of ±3 hours the bands get so wide that a ranking would mean little, so we turn rankings off. Without any time we show a noon example, clearly dimmed, and no rankings.
How we choose your places
For each of 1,229 cities we measure the distance to every line. A line counts fully within 100 miles (150 km) and fades smoothly to nothing by 620 miles (1,000 km). Each line carries a weight for each lens (a Jupiter overhead line is a strong career line; a Venus setting line is a strong love line). A city's score is its best line plus half of its second best, so places where many lines meet don't pile up points they haven't earned.
We list a city only if it scores at least 1, sits within 70° of the equator, and isn't within 100 km of a city already on the list. The region filter narrows all of this to one part of the world. The weights are our own editorial model, written down on the method page.
Time zones we get right
Many birth times go wrong before any planet is computed. Browsers don't know the full history of some time zones before 1970, so we ship a corrected table for the zones where it matters (Amsterdam in 1935 was 1 hour 19 minutes 32 seconds ahead of UTC, not one hour). Before standard time reached a town, clocks followed the Sun, so we use your birthplace's own local mean time. When clocks jumped forward or fell back on your birth night, we say so and let you choose. You always see the offset we used, and you can set it yourself.
Privacy
Your birth details stay on this device. The math runs in your browser; nothing goes into the link; there's no account. The city list is a set of files on this site, fetched by first letter, so the most a request reveals is that someone typed a word starting with that letter. "Remember my birth details" is off unless you tick it, and it saves only in this browser.
What this isn't
The positions are precise: within 1 arcminute, checked against Swiss Ephemeris and Astro-Databank. The meaning is astrology, a symbolic language, not science. Places that ask more of you sit under Go gently, never under anything scarier. Please don't move, travel or make money decisions on astrology alone: check costs, visas, official travel advisories, and how a place actually feels when you're there.