Almost nobody chose the city they live in. This is the ten-minute exercise that gives you a real answer: a map of your own lines across the world, and a ranked shortlist of cities with a reason attached to each one.
Nobody Actually Chose
Ask anyone why they live where they live and you get the same handful of answers. They were born there. A job moved them. They followed somebody. The rent was cheap that year and then fifteen years went past. Out of every city on earth, almost nobody has ever sat down and picked one on purpose.
Which is strange, because it is one of the biggest decisions in your life and most people made it by accident. And most of us carry a quiet suspicion that there is somewhere out there that would suit us better, with absolutely nothing to base it on.
This guide gives you something to base it on. It will not hand you the truth, and I am straight about that further down. What it will do is give you a real map, a ranked list of cities, and a reason attached to each one, which is more than most people have ever had when thinking about this.
What you are actually doing: working out the position of the sky at the exact minute and place you were born, then laying that over a world map. Where the lines fall is a real calculation. What the lines are supposed to mean is an old interpretive tradition. Both halves are interesting and they are not the same kind of thing.
Get The Time Right First
This is the one thing that decides whether the whole exercise is worth doing. Everything here is calculated from a single moment, and the sky moves fast.
The planets barely shift over a few hours. The horizon does not. It rotates through the entire zodiac every twenty four hours, which means your rising sign changes roughly every two hours, and the map lines move with it. An hour of error and you are reading somebody else's chart.
Where to find it. Your birth certificate, if you have the long-form version. Many short-form certificates leave the time off. Failing that, your mom will usually remember within half an hour, and half an hour is workable. Hospital records are the last resort and most countries will release them to you on request.
To the minute. Everything works.
Within 30 minutes. Chart and map work roughly. Precise city rankings do not.
Within 2 hours. Planets only. Rising sign, houses and map are unreliable.
No idea at all. Sun and most planets still work. Everything location-based does not.
If you genuinely have no idea, do it anyway but skip the map half. A chart with no birth time still tells you something. A map with no birth time is noise.
Prompt One: The Read
Open ChatGPT and paste this in. It asks you the questions itself, so you do not need to prepare anything except the date, the time and the town.
Ask me for my date of birth, the time as close as I know it, and the town I was born in, then work out my actual chart from that exact moment. Do the calculation properly with code rather than from memory, and if you can't run it, tell me instead of guessing. Then tell me what it says about me in plain English, no vague horoscope language. Go at the specific patterns rather than my star sign, be honest including the parts I won't enjoy, and tell me which parts are real astronomy and which parts are interpretation.
Why it is worded like that. Three things in there are doing real work. Do the calculation with code stops it working from memory, which is where wrong answers come from. If you can't run it, tell me gives it permission to admit a limit instead of inventing something plausible. And go at the patterns rather than my star sign is what turns this from a horoscope into something specific.
Ask for the unflattering parts explicitly. Without that line you get a flattering read, because the default is to be nice. With it you get something worth reading.
Prompt Two: The Map
This is the half people stay for. Run it straight after the first one, in the same conversation, so it already has your chart.
Now work out my astrocartography lines. Generate a full visual map of where my lines fall across the world and make it interactive, with every line drawn on it and the cities marked where they cross. Then for each of those cities, tell me what that line is meant to bring and what the catch is. Rank them best to worst for me, and tell me which one you'd actually pick if you were me and why.
What comes back is a map of the world with a set of lines running across it, dots where they cross, and a list of cities underneath. Ask it to rank them, because an unranked list of forty cities is useless and a ranked list of eight is a decision.
If it will not draw the map. Some versions describe the map instead of building one. Reply with: "build it as an actual interactive visual I can look at, not a description." That usually does it. If it still will not, ask for the line positions as a list and the section still works, you just lose the picture.
What A Line Actually Is
This is the bit nobody explains, and it is simpler than it sounds.
Your chart is the sky as seen from one specific spot on earth. Stand somewhere else and the same sky sits at a different angle. A planet that was low on the horizon where you were born might have been directly overhead if you had been born a thousand miles east.
An astrocartography line marks every point on earth where a given planet would have been in one of four key positions at the moment you were born: rising on the eastern horizon, setting on the western one, directly overhead, or directly underfoot. Ten planets, four positions, so the map ends up with a lot of lines on it.
Rising (AS). How you come across there.
Overhead (MC). Career and reputation there.
Setting (DS). Relationships there.
Underfoot (IC). Home and private life there.
A city sitting within about 150 miles of a line is treated as on it. That is the convention the software uses, so do not discount a city because it is a little off.
Reading Your Shortlist
You will get more cities than you can use. Here is how to cut it down to something real.
1. Throw out anywhere you would never go. A line through a country you have no right to live in and no desire to visit is not a shortlist entry. Be ruthless. You are looking for places you would genuinely consider.
2. Look for crossings, not single lines. A city where two of your lines cross is far more interesting than one sitting on a single line. Ask which cities have more than one and start there.
3. Read the difficult lines too. Every chart has lines that are traditionally read as hard going. Those are more useful than the good ones, because it is worth knowing if the city you already live in sits on one.
4. Check where you are now. Ask it explicitly what your current city sits on. This is the single most interesting question in the whole exercise and almost nobody thinks to ask it.
What does my current city sit on, and how does it compare to the top three on my list? Be honest if it's a bad fit and be honest if it's actually fine.
What Is Real And What Is Not
Real. The positions. Where every planet sat at the moment you were born, and where the lines fall across the world, is astronomy. It comes off the same ephemeris data observatories use, and any two tools doing the calculation properly will agree with each other to a fraction of a degree. If your chart says the Moon was in a certain place, it was.
Not real. What any of it means. There is no known mechanism by which the angle of a planet at your birth shapes your personality or your prospects in Lisbon, and controlled testing has never found astrology to beat chance at predicting either. Everything interpretive in your output is a symbolic tradition being applied consistently, which is not the same as being true.
Some of it will land hard, and that is worth understanding. A reading written with enough specificity will always contain something that feels uncannily accurate. That is a fact about how people read descriptions of themselves, not evidence.
So use it the way I do. As a structured way of thinking about a question you have probably never sat down with, and a genuinely good list of cities to go and look up. Not as an instruction. And if one city keeps pulling at you, my Claude travel planning guide can plan a trip there so you can see it for yourself.
When It Goes Wrong
Says it cannot calculate. Tell it to use code. If it still cannot, do not let it guess.
Gives a chart with no working. Ask how it calculated it. If the answer is vague, redo it.
Describes the map, will not draw it. Ask for an interactive visual, not a description.
Reads like a horoscope. Tell it to go at the patterns, not the signs.
Only flattering. Ask directly for what you will not enjoy hearing.
Lists forty cities. Ask it to rank them and cut to eight.
The one real failure mode: it produces a confident chart with invented positions and no warning. You would never know. That is why the first prompt tells it to say so if it cannot calculate, and why you should ask how it got there if anything looks off.
The Quick Reference
1. Get the time. Birth certificate. Within 30 minutes is workable.
2. Run prompt one. It asks the questions, then reads your chart.
3. Ask for the bad parts. Or you will only get the flattering half.
4. Run prompt two. The map, the lines, the ranked cities.
5. Find the crossings. Two lines beat one, every time.
6. Check where you live. The question nobody thinks to ask.
7. Keep it in proportion. Real positions, interpretive meanings.
Your ten minutes tonight. Find your birth time. Run prompt one, ask for the unflattering half, then run prompt two and ask what your current city sits on. That last question is the one that makes people go quiet. If you liked this one, my what AI notices about you prompts are the same kind of rabbit hole, pointed at your own chats instead of the sky.