What’s in a Name?

Is it Seventh Avenue or 7 Avenue? What about Adam Clayton Powell Boulevard and Fashion Avenue? Does Sixth Avenue extend north of Central Park? These are questions you may ask yourself as you navigate NYC.

Street names can be confusing. Geosupport, the Department of City Planning’s geocoding application is designed to handle streets with multiple names and multiple spellings. Each street segment has a primary, principal, and preferred street name, along with many other variant names and spellings. Keep reading to understand what this all means.

Figure 1. A modern redrawing of the 1807 version of the Commissioner’s grid plan for Manhattan.

To begin, how did it get so complicated?

In 1807, the New York State Legislature appointed a commission to create an orderly street layout for the city. The Commissioners couldn’t do anything about existing streets in lower Manhattan, but they created a grid for the rest of the island, with the numbered avenues and streets that we know so well. Over time, streets were renamed or co-named, often to commemorate a person or an event. When Central Park was built, Eighth Avenue on the west side of the park became Central Park West. Back before the city was developed, a street could be renamed and the former name was dropped entirely and no longer used for that particular stretch of the street. This is what happened with Central Park West. Eighth Avenue ends at Columbus Circle (West 59 Street) and Central Park West starts. Central Park West has its own set of address numbers, starting with 1 Central Park West and increasing as you head north. Residents of the El Dorado apartment building at 300 Central Park West, cannot get their mail delivered to 300 Eighth Avenue. This address belongs to a building between West 25 Street and West 26 Street.

Central Park West ends at West 110 Street and Eighth Avenue resumes. In 1977, Eighth Avenue north of West 110 Street was co-named Frederick Douglass Boulevard. The buildings on the new Frederick Douglass Boulevard already had Eighth Avenue address numbers, and these remain unchanged. At its southern end, buildings on Frederick Douglass Boulevard start with addresses in the 2000 range. For instance, 2050 Frederick Douglass Boulevard is at West 111 Street. Both the U.S. Postal Service and DCP’s Geosupport System recognize 2050 Eighth Avenue and 2050 Frederick Douglass Boulevard as the same location. But how?

How does Geosupport keep it all straight?

Since many streets have more than one variant name, each with multiple spellings, Geosupport has a set of street codes to handle this — B5SC, B7SC, and B10SC. The B5SC consists of a 1-byte borough code (ranging from 1 to 5 for the five boroughs of NYC) and a 5-byte street code. Streets with the same B5SC have the same primary street name. For example, 7 Avenue, Fashion Avenue and Adam Clayton Powell Jr Boulevard all have 110510 as their B5SC. Addresses are numbered along these streets as if they were one street, even though 7th Avenue is co-named Fashion Avenue in the Garment District and Central Park separates A.C. Powell Blvd from the rest of 7th Avenue. The primary street name for these locations is 7 AVENUE.

Figure 2. User Programming Guide’s table of street codes for 7th Avenue

The B7SC consists of the B5SC plus an additional 2-bytes. This pair of digits is called the Local Group Code (LGC). When the LGC is added to the B5SC, it becomes the B7SC and identifies the name applied to a section of the street (hence the term “local”). As you can see in Figure 2, in the fifth column, Adam Clayton Powell Jr Boulevard, Fashion Avenue, Saint Vincents Square, and 7 Avenue, have different LGCs. The B7SC for A. C. Powell Blvd is 11061001 and for Fashion Avenue, it’s 11061002. The B7SC is assigned to a set of local group street name spelling variants — like ACP, POWELL BOULEVARD, A C POWELL BOULEVARD, etc. One of the LGC spelling variants is flagged as the principal spelling for that LGC. A C Powell Boulevard has a principal spelling of ADAM CLAYTON POWELL JR BOULEVARD.

As you can see in Figure 2, Adam Clayton Powell Jr Boulevard can be abbreviated in many ways, but each variant spelling has the same B7SC. Three additional bytes are added to the B7SC to create the B10SC, which identifies a unique spelling of the B7SC. These three bytes are referred to as the Street Name Code (SNC). For example, in Figure 2, you can see how each variant spelling of Adam Clayton Powell Jr Boulevard has the same LGC but has a different SNC. As mentioned above, one of these variants is designated as the principal for this set of local group street name spellings.

To recap:

• Street names that share the same B5SC are either co-names or variant spellings for all or some of the street.
• The B5SC determines the primary street name, which is the same for all streets with that B5SC.
• The B7SC determines the principal street name. Street name spellings that share the same B7SC are variant spellings with one spelling designated as the principal.

Figure 3. Table of different street names for 7 Ave.

Now that you know where the primary and the principal names come from, what about the DCP Preferred name? This is the legal street name on the city’s official street map. In Figure 3, you can see that the DCP Preferred option is ADAM CLAYTON POWELL JR BLVD for the portion of 7th Avenue north of Central Park. The DCP Preferred name is used as the street label in LION, the City’s centerline dataset.

Figure 4. Accompanying map to Figure 3. The street highlighted in blue indicates the DCP preferred name for this street is Adam Clayton Powell Jr Blvd.

When?

When would you use one name versus another? It’s really a matter of choice. When you call Geosupport with an address, you may choose to include a normalized address in your output file. Geosupport offers four different options for the street name in your output file — user input, primary, principal, or DCP Preferred.

“User input” will return your input street name with some minor changes to grammar and standardization (or normalization) rules. For example, a user input of “7th Av” will be returned as “7 AVENUE,” with ordinals removed and abbreviations spelled out.

“Primary” will return the street name selected for the B5SC, which may not be the name that people associate with that section of the street. For example, a user input of “ACP” will be returned as “7 AVENUE” (instead of “ACP”). Similarly, a user input of “Seventh Av” will be returned as “7 AVENUE.”

“Principal” will return a more officially recognized spelling for your input street name. For example, a user input of “ACP” will be returned as “ADAM CLAYTON POWELL JR BOULEVARD” (instead of “ACP”).

“DCP Preferred” will return a street name that is the legally designated name for that particular stretch of the street. For example, a user input of “2000 7 Av” (north of Central Park) will be returned as “2000 ADAM CLAYTON POWELL JR BOULEVARD.” This returned name will match the street name labels in LION. If there is no legally designated name, such as for highway ramps, DCP decides what name to designate as preferred.

The next time you come across streets with multiple names, I hope this blog posting will provide some insight and help you make sense of the different options available in Geosupport.