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I am generalizing geological map, for initial process I am dealing with small polygons which are less than minimum separability unit and try either remove them or enlarge. For the first step I am converting geological map scale 1:25 000 to map scale 1:50 000 scale.

Based on the theory we have less space for the same amount of features, and some of them should be eliminated based on area, importance and etc. Here, question is, what amount of features should be kept to the successive map scale.

I have slight memory from my old Cartography class that 25% of overall features should be maintained, though I could not find proper reference to link it with the fact.

Does anyone know about this rather simple but important issue?

closed as primarily opinion-based by Vince, whyzar, PolyGeo Jan 20 '17 at 5:07

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

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    I used to work for NRCS and when I work with soils people on using their soils data. What I found is that if there is a less than 10 acres, they usually merge with the other soils. That kind of thing...but I am not sure about geology. Have you spoken to GIS Specialist at a geology agency about that ? Is that what you were asking about ? – PROBERT Jan 19 '17 at 18:05
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    You ask one of the fundamental questions in cartography and i fear there is no easy answer, especially regarding eliminating or enlarging small polygons. – Martin F Jan 19 '17 at 20:34