Editing Automatic label placement (section)

==Rule-based algorithms==
Rule-based algorithms try to emulate an experienced human cartographer. Over centuries, cartographers have developed the art of mapmaking and label placement. For example, an experienced cartographer repeats road names several times for long roads, instead of placing them once, or in the case of Ocean City depicted by a point very close to the shore, the cartographer would place the label "Ocean City" over the land to emphasize that it is a coastal town.<ref>{{cite book|last=Slocum|first=Terry|title=Thematic Cartography and Geovisualization|year=2010|publisher=Pearson|location=Upper Saddle River, NJ|isbn=978-0-13-801006-5|pages=576}}</ref>

Cartographers work based on accepted conventions and rules, such as those itemized by Swiss cartographer Eduard Imhof in 1962.<ref name="imhof">Imhof, Eduard, “Die Anordnung der Namen in der Karte,” Annuaire International de Cartographie II, Orell-Füssli Verlag, Zürich, 93-129, 1962. English Translation: "Positioning Names on Maps," ''The American Cartographer'', V.2 #2 (1975), pp.128-144</ref> For example, New York City, Vienna, Berlin, Paris, or Tokyo must show up on country maps because they are high-priority labels. Once those are placed, the cartographer places the next most important class of labels, for example major roads, rivers, and other large cities. In every step they ensure that (1) the text is placed in a way that the reader easily associates it with the feature, and (2) the label does not overlap with those already placed on the map.

However, if a particular label placement problem can be formulated as a mathematical optimization problem, using mathematics to solve the problem is usually better than using a rule-based algorithm.<ref>{{Cite journal |last=ZORASTER |first=STEVEN |date= 1991|title=Expert Systems And The Map Label Placement Problem |url=https://utppublishing.com/doi/10.3138/P75V-T152-7U53-4170 |journal=Cartographica |volume=28 |issue=1 |pages=1–9 |doi=10.3138/P75V-T152-7U53-4170 |issn=0317-7173}}</ref>