How did people draw maps in ancient times?

About the ancient method of drawing maps is actually quite interesting, that time there is no modern so developed measurement technology, such as infrared or aerial photography, etc., basically all rely on manpower to realize. The most commonly used method is to use artificial pace measurement, that is to say, their own national jurisdiction, each county will be a word of topographic data statistics, and then uniformly reported to the court, and then summarized by the court a complete map. The method of measurement is very simple, for example, when drawing the map of the city, the specialized drawing personnel will take a well-marked size of the twine, of course, the rope will be very long, according to the various nodes of the city for measurement, and finally draw the appearance of the city and mark the size.