Locating Maps in UO Libraries

LC call numbers for maps can be broken down into several basic components

where,
what,
when,
which scale, and
who created it.

Not every component is present in every call number.

Where is represented by the letter G and four numbers.

• Maps with the G4290 through 4294 are maps of Oregon.
• Maps with the G3701 call number stem are U.S. historical maps. This includes U.S. territories before they became states and Indian reservations.

Each geographic area can be additionally broken down by subdivisions, based on the last digit. For example, if G4290 is the general call number for the State of Oregon:

• G4291 indicates that the map is about a specific subject covering the state of Oregon (for example, mineral resources).
• G4292 indicates that the map is about a region or natural feature within the State of Oregon (for example, Wallowa National Forest).
• G4293 indicates that the map is about a major political division (for example, Lane County).
• G4294 indicates that the map is about a city or town (for example, Eugene).

The subdivision indicator is often followed by a "geographic cutter" that is assigned based on the name of the area represented. These are a letter/number combination that places the subdivisions of a region in alphabetical order.  For example, we can tell that maps with a call number G4293 are maps of a county in Oregon. G4293 .L3 are Lake County maps, G4293 .L4 are Lane County maps, and G4293 .L5 are Lincoln County maps.

What is indicates the subject matter of the map.

This is an additional letter/number combination that appears after the G call number stem and the geographic cutter (if there is one.) The what tells you what type of features are shown on the map. Catalogers have a sizeable book that tells what these cutters are.  You won't need to know what they mean to browse the collection or locate a map you found in the catalog.  It is useful to know that the subject cutter groups maps by subject matter within the larger call number stem.  For example, Lane County Road maps might be expected to all have call numbers beginning with G4293. L4 P2. P2 is the subject cutter for road maps.

When—the date of publication—is represented by a year. If the year of publication is not known, it will have a question mark and may also have one or more dashes. For example, 197-? indicates that the cataloger believes that the map was published sometime in the 1970s.

Which scale is only used for sets of maps all in the same scale, such as topographic sets. It is represented by the letter s and a number. For example, s250 represents the scale of 1:250,000.

Who—the author of the map—is represented by a period, one letter 9initial of last name or organization), and one or more numbers, such as .U5. This is called a Cutter number or a Cutter.