There are various map features which are not easily identified with the map key.
I’m not sure whether their rendering has been updated without updating the key, or if the key was not created with the same detail or exact appearance as they are rendered on the map to begin with. In any case, I propose that the map key should be reviewed and revised to more accurately and completely match the actual appearance of how features are rendered on the map, and to include all features and symbols/icons used on the map.
I feel that this is quite a crucial topic that should not be ignored or dismissed because it is so intimately and directly related to the usability of the map. If one is unable to interpret the map and identify features on the map, then the map loses value and utility.
What is the point of indicating something on a map which can not be identified or interpreted?
What purpose and/or value does a map have if it can not be interpreted?
Some examples I have noticed:
Fill Colors: Many of the colors on the key do not seem to match their actual rendering, and many features are rendered with some sort of recurring pattern which is not indicated on the key. This is particularly important since many of the colors used on the map are quite similar.
Examples: Military use areas have diagonal fill lines not indicated on the key, the color also appears different on the key than on the map; forest areas on the map have tree icons not present on the key
Tracks (highway=track): The key indicates Tracks to be represented by a dotted line of uniformly sized small dashes; however, on the map Tracks are represented with a dotted line composed of a repeating sequence of dashes of different lengths.
Maps typically use different sequences of dashes of varying length and width to indicate different features, the key must accurately depict such differences if it is to actually be of any value or use.
Administrative Boundaries: The key does not indicate the meaning of the various patterns of dashed/dotted lines
Peaks: The map shows peaks as solid triangles whereas the key shows a rather odd shape
Symbols/Items missing from the key: Quarries and their icon, power lines and towers, marsh/swamp areas, cliffs… just to name a few
Perhaps it would help if the example patches of colored areas on the key were larger to include the fill patterns as well as their borders (which are often of a darker shade). While this has the disadvantage of increasing the size of the key, the entire purpose of the key is nullified if it can not be effectively and reliably used to identify features; it seems obvious that a larger key is preferable to one that is useless.
Perhaps the key could also be dynamic in such a way that it only displays items which are currently visible/present. I feel that this would be especially beneficial as it would at least prevent the mis-identification of features for something not even present in the current view while simultaneously reducing the size of the key significantly in many situations.
The accuracy and completeness of a map’s key or legend is of paramount and fundamental importance to that map, its value can hardly be overestimated or exaggerated.