This tool makes it easy
to label various lunar feature groups on your screen display, as well as on
your printed maps. When you open the
Labeler, the dialog box (shown below),
appears on your screen. Simply use your
mouse to place check marks next to the feature names that you want displayed on
the map, and click, Apply.
Unchecking a box and
clicking, Apply again removes the
labels. Labels can be useful when
exploring the moon on your computer monitor, and are a necessity when you are
printing maps for use at the telescope eyepiece.

The Labeler also gives you have the ability
to proportionally adjust all font sizes simultaneously. This allows you to quickly set an appropriate
label scale, as you zoom the map in and out.
Simply adjust the slider, by moving it towards smallest or largest, and
click, Apply.

In order to help reduce
map overcrowding, all features types, (with
the exception of crater names), are identified by a two-letter prefix,
derived by the IAU (International Astronomical Union) and used by the USGS
(United States Geological Survey). The
designations used are as follows:
CA (Catena - Crater Chains) DE (Domes -Volcanic
Peaks) DO
(Dorsa - Ridges)
LC (Lacus – Small
Plains) PA (Palus - Small Plains) SI (Sinus - Small
Plains)
MOs (Montes - Mountains) MO
(
PR (Promontoria -
VA (Valles -Valleys) OC (Oceanus - Large
Dark Region)
NOTE: Checking all of the feature groups at once
will overload the map with data and will also increase the map redraw time, so
be careful not to over annotate.
You will notice that Lettered Sub-Craters and Lunar Domes are not included within
the group labeling categories. Since the
Lettered sub-craters number in the thousands, the map would be completely
overwhelmed by the label density. In the
case of domes, they tend to cluster in groups that are extremely close to one
another, so label overlapping will often make dome labels unreadable.
Both groups of features
can be easily identified by using the Hover,
or they can be labeled by using the custom labeling capability found in the Feature
Finder.