The structure feature types that volunteers are currently collecting include schools, colleges and universities, fire and EMS stations, law enforcement, prisons and correctional facilities, hospitals, ambulance services, cemeteries, and post offices. Volunteers can collect and update the 10 different structure feature types in all 50 states, as well as in Puerto Rico and the U.S. Virgin Islands.
See our structure list for a quick summary of what these points entail. Click on the links below for additional information on each structure type.
What is a school?
A school is a building where children are taught in any grade from K through 12.
What types of schools should I collect?
Schools are typically divided into three separate categories based on grade levels offered: Elementary, Middle, and High school. We also include a fourth category (i.e., General School) for those schools whose grade levels do not fall into one of these categories. This is most often the case for schools that combine two or more categories into one organization, such as K-12 schools.
It is important to note that there is no ultimate black-and-white definition for what category a school falls in. Each school district structures their schools in a unique way, and this structure is the ultimate deciding factor of what category a school falls into.
Here are some general guidelines for what each school category entails:
EXAMPLE: If a school does not self-identify, the table below provides a few scenarios that you might encounter:
Where do I place a school structure point?
Most schools typically have one building and the point should be placed at the center of the building. If a school has multiple buildings as part of the same complex, place the point at the center of the complex.
Many schools, especially rural schools, have multiple institutions all in one building. Should these be depicted as one school, or multiple schools (elementary school, middle school, high school)? This generally is decided based on information from the school website or the state department of education website. If these websites list separate schools at the same address, then add one point for each school, with each point placed within the footprint of the building. Our March 2019 Newsletter contains an article titled “Rare Find: 4 High Schools in One!” that walks users through this very scenario.
For more information on how to identify a school building, check out the “Aerial Photo Interpretation Part 9: Schools” article in our March 2019 Newsletter.
Where can I find authoritative lists of schools?
The best place to find information about a school is on a dedicated school and/or district website. These websites are the first to reflect any changes in pertinent information (e.g., name, address, etc.) and therefore are typically the most accurate. If a dedicated school and/or district website cannot be found (as may be the case for smaller, rural, and/or private schools), there are many secondary sources that compile information from authoritative sources into an aggregate list. Examples of secondary sources include:
Insiders Tip: Many schools have websites or official Facebook pages that include a news section or event calendar. Before assuming all the information is valid, check to see if recent posts have been made to the page’s news or events section. There are scenarios where a school may have recently closed but its website is still online. Checking the news or events sections for recent updates helps to verify if the school is still in operation.
Check out our Authoritative Sources List for more on the types of sources that are acceptable.
What is a College / University?
The key indicator of a college or university is that the institution grants degrees. There are 4 types of degrees: Associate, Bachelor, Master, and Doctoral.
Degree-granting is generally regulated by the States, with each having a higher education agency to oversee degree-granting institutions. The U.S. Department of Education has a list of these higher education agencies that maintain lists of the degree-granting institutions in their state.
For the most part, this degree-granting requirement leaves out vocational schools (also called trade schools, career schools, or technical schools), which generally grant certificates but not degrees; these should be captured as a Technical / Trade School. An exception is technical colleges which do grant degrees; these should be captured as a College / University structure.
It is important to note that we are not collecting university extension locations whose primary mission is to perform community outreach. If a university manages an alternative campus and its title includes the term “Extension”, this point can be collected so long as this campus serves students enrolled in a degree-granting program. If the alternative “Extension” campus only provides education and outreach to the community, this does not meet our definition of a College / University and therefore is not a point we would collect. Check out this Q&A entry for more on how to handle University extensions.
Where can I find authoritative lists of College / University structures?
An institution’s individual website is the best place to find authoritative information on a College / University. Therefore, it is highly recommended that users confirm the information on these lists by locating the website for each College / University listed.
The closest thing to a national list may be the National Center for Education Statistics (NCES). NCES maintains a database of primary, secondary, and higher education (aka, college) institutions. Users can search the NCES database for colleges.
Each state also has a higher education agency that may include a list of colleges and universities within their state.
Where do I place a College / University structure point?
In general, each college and/or university campus should be represented by a single structure point placed on the administrative building for that institution. If one does not have firsthand knowledge of the location of the administration building, it can usually be found on the school's campus map. If the location of the administration building cannot be determined, then place the structure point on a building at the center of the campus.A university campus may contain several colleges or schools (i.e., College of Arts, College of Sciences, School of Business, School of Medicine), but so long as these are units of the same university and located on the same campus, then they should be not be added as separate points. One point would represent the university or college. However in some cases, separate institutions may share the same campus (for example, the Auraria campus in Denver, Colorado is home to Metropolitan State University of Denver, the University of Colorado Denver, and the Community College of Denver) – in this case each institution should be represented by a separate point. Some colleges, especially in an urban environment, may have multiple campuses or widely dispersed buildings. In general a separate campus should be represented by its own structure point. However, if a dispersed college location consists of a single building, or a few rooms in a single building, then use your best judgment as to whether it is important enough to be considered a campus and therefore justify a separate structure point. Medical schools that are co-located with hospitals should be represented by a separate College / University structure point. The associated hospital would be represented as a separate Hospital structure point.
What is a Fire Station/EMS Station?The basic requirement for a Fire Station/EMS Station is that the structure contains a fire engine. It may or may not also house an ambulance. Fire personnel visit the station on a regular basis to keep the equipment clean and shiny and ready to go, and before being dispatched into the community for an emergency. It may only have volunteer responders and not full time personnel on site.
Fire department web pages are the best source of data, but may not specify the locations of stations. Fire Departments in smaller and/or rural communities may have their own Facebook page in place of a website. Page 6 of our July 2017 Newsletter has an infographic on Facebook as an authoritative source.
County and city websites also often have information about fire departments through their emergency management offices.The US Fire Administration has the most complete nationwide list of fire departments, however this data may be dated and not complete. Their list is the result of a voluntary National Fire Department Census wherein during the years 2001 to 2004 fire departments filled out and handed in survey forms. The USFA is "continuously working to encourage more fire departments to participate in the census," however, since the original census now is almost 20 years old, some of the information is out of date. The list can be downloaded for the entire nation or by state. The list is by fire department, so it will tell you how many stations a Fire Department has, but not where they are. There may be some contact information, such as address, phone number, and website.Check out our Authoritative Sources List for more on the types of sources that are acceptable.
Try to find out the official name of the station; it often has the format: <fire-department-name> <station-name>. For example "Denver Fire Department Station 1". Official station names sometimes have either a "-" or a "/" in the station name, and while the Attribute Guidelines say that special characters should be avoided, they can be used if necessary to document an official fire station name.
Check out our Name and Address Formatting guide for more on how to properly name fire stations.
What is a Law Enforcement structure?
When editing Law Enforcement structures, you may occasionally come across a county jail with the symbol of a Law Enforcement structure. If you encounter any of these points, you can either skip or delete them. This is because these are not structures we are actively collecting. Check out this Q&A for more on how to handle county jails.
Sometimes the sheriff’s primary office is housed in the same building as the county jail. If the sheriff’s office is in the same building as the jail and dispatches into the community, then this is a point that we would collect as a Law Enforcement structure. However, if the sheriff’s only purpose in the building is jail security (i.e., it does not dispatch officers into the community), then this is considered part of the county jail and therefore is not a point we are collecting.
Similarly, be aware of bailiffs. You may come across law enforcement points that are close to (or located at) county courthouses. When reviewing these points, make sure to determine whether officers at these locations dispatch into the greater community or if their primary role is to assist the courts. If that location’s only duty is to assist the courts, then it is considered a bailiff. Since we are not collecting bailiffs at this time, please use the Comments field to document your findings and delete these points.
Our Q&A community includes several entries for Law Enforcement structures, including entries about School Police, County Jails, Community Oriented Police Houses, Constables and Peace Officers, and Park Police.
Where can I find authoritative lists of Law Enforcement structures?
There are no authoritative lists of Law Enforcement structures.
County and city websites are the best sources for this information and typically have a separate page for law enforcement offices within their boundaries. Law enforcement offices in smaller and/or rural communities may have their own Facebook page in place of a website. Page 6 of our July 2017 Newsletter contains an infographic on properly using Facebook as an authoritative source.
Where do I place a Law Enforcement structure?
Most Law Enforcement structures have one building. If this is the case, place the point at the center of the building. If the law enforcement office operates out of the same building as a City Hall / Town Hall and/or Fire Department, space the points out on the building so that they are not overlapping.
For more information on how to identify a Law Enforcement structure, check out the “Aerial Photo Interpretation Part 7: Law Enforcement” article in our September 2018 Newsletter.
How should I name Law Enforcement structures?
County sheriff's offices should be named like this: Jefferson County Sheriff's Office. Police departments for smaller cities generally have only one office which should be named like this: Lakewood Police Department; but larger cities may have Precinct or Division offices which would be named like this: Denver Police Department District 1 Station.
Check out our Name and Address Formatting guide for more on how to properly name Law Enforcement structures.
What is a Prison / Correctional Facility?
The Federal Bureau of Prisons website provides an authoritative list of federal prison facilities. Only Institutions, Private Facilities, and Correctional Complexes should be included -- not offices or training centers.
State Department of Corrections websites also list private and public prisons in each state.
Where do I place a Prison / Correctional Facility structure point?
If a prison has a single large building, place the point at the center of the building. If the prison does not have a distinctive single building, then place the point at the center of the prison facility.
If a prison complex has more than one named facility, each with its own separate grounds or building, then place a prison point on each facility. For example, the Florence Federal Correctional Complex has three facilities (Florence Federal Correctional Institution, Florence High Security United States Penitentiary, and Florence Administrative Maximum United States Penitentiary), and therefore should be represented by three structure points. It may be difficult to determine from aerial imagery which facility is which, but you may be able to tell from Google Street View™, from an online facility map, or by examining a photo of the prison entrance (if it exists on the prison webpage) and comparing this to the building footprint in the satellite image. If it cannot be determined which facility is which, then place all facility points adjacent to each other near the centroid of the entire facility.
For more information on how to identify a Prison / Correctional Facility, check out the “Aerial Photo Interpretation Part 4: Prisons / Correctional Facilities” article in our March 2018 Newsletter.
How do I name a Prison/Correctional Facility?
Use the name of the facility as it appears on the facility website. For federal prisons, the website uses several formats for names, but the format where the prison name comes last is preferred (e.g., United States Penitentiary Florence High).
What is a Hospital / Medical Center?
Where can I find authoritative lists of Hospital / Medical Centers?
Refer to state health departments for authoritative lists of hospitals in a given state. There are many types of medical facilities, but only those that are listed as hospitals should be included.
The US Department of Veterans Affairs also maintains an authoritative list of their facilities. Only VA Health Care System and VA Medical Centers should be included. Outpatient VA facilities are not included.
A hospital’s individual website is still the best place to find authoritative and current information on a Hospital / Medical Center. Therefore, it is recommended that users confirm the information on these lists by locating the website for each hospital listed.
Check out our Authoritative Sources List for more on the types of sources that are acceptable.
Where should I place a Hospital / Medical Center facility structure point?
Some hospitals have only one building, in which case the point should be placed at the center of this building. Larger hospitals may either have a larger complex building, or consist of several individual buildings on a medical campus. If a hospital has multiple buildings as part of the same campus, place the point at the center of the campus.
For more information on how to identify a Hospital / Medical Center facility, check out the “Aerial Photo Interpretation Part 5: Hospitals” article in our May 2018 Newsletter.
What is an Ambulance Service?
An ambulance service facility is a building that houses vehicles and personnel to transport emergency patients and administer emergency medical treatment but does not include ambulances operated by fire departments or hospitals.
If an ambulance is located in a fire station and is operated by fire department personnel, it is considered part of the fire department and not a separate ambulance service for our purposes. However, it is not uncommon for contract, private or non-profit ambulance services to operate out of fire department stations through a government contract or mutual aid agreement. (The fire department’s website usually specifies the relationship between the two entities.) These facilities, which are not operated by the fire department personnel, meet the criteria for ambulance collection.
Both for-profit and non-profit ambulance services may operate out of their own facilities separate from fire departments and are included as ambulance service facilities.
Do we include air ambulance (helicopters and fixed-wing aircraft) locations as Ambulance Service locations?
Where can I find authoritative lists of Ambulance Services?
Ambulance services generally are licensed by counties or by state, so you may find information listed on government websites. State health departments or state emergency management divisions may also may maintain lists of ambulance services.
Where do I place an Ambulance Services structure point?
Most ambulance services structures have one building. If this is the case, place the point at the center of the building. If the structure operates out of the same building as a Fire Department and/or Law Enforcement facility, distribute the points on the building so that they are not overlapping.
Stations can generally be recognized in Aerial Imagery or in Google Street View™ because the stations have large bays with overhead doors and large concrete pads outside where the ambulances can park.
For more information on how to identify an ambulance services structure, check out the “Aerial Photo Interpretation Part 6: Ambulance Services” article in our July 2018 Newsletter.
What is a Cemetery?
Cemeteries are defined as places where the dead are buried, including graveyards, burial sites, and columbariums. Pet cemeteries are not included.
Single graves within burial sites are generally not included, unless they are the graves of famous historical figures. An example of a single grave for a famous historical figure is the burial marker for Thomas Jefferson (i.e., the Jefferson Tomb) outside of his former Monticello residence.
Where does our Cemetery database originate?
There are two principal sources of cemetery data in the TNMCorps Structures database: US Geological Survey (USGS) Topographic maps and the USGS Geographic Names Information System (GNIS).
US Geological Survey topographic maps were produced from about 1879 to 1992 using a combination of aerial photographs and on-the-ground surveys and inventories. In addition to large more-modern cemeteries, many small cemeteries of historical significance were mapped, and these are included in our database.
The GNIS has cemetery information built over time from a variety of sources. One example of this is the USGenWeb Project. This volunteer project, started in 1996, serves as a repository of internet resources for genealogical research in every county and state in the country.
Because many historical cemeteries have been carefully documented and included in the database, please do not remove cemeteries from the database simply because they are not visible in aerial imagery. Only remove cemeteries if the imagery shows without a doubt that the landscape has been altered (for example, a shopping center now exists where the cemetery used to be), or if you have local or on-the-ground knowledge that the cemetery has been moved or destroyed, or that the graves have been disinterred.
What are authoritative sources of information about cemetery locations?There is no single complete authoritative source of information about cemeteries, but there are many internet resources that together can provide a fairly complete list of cemeteries:
Where do I place a cemetery structure point?
The general rule is to place the cemetery structure point at the center of the burial grounds. A single point should be placed even if a cemetery has a combination of facilities (e.g., graves, mausoleums, columbariums).
Some columbarium-only facilities are located in church buildings, although their presence may be difficult to ascertain or validate; they should be represented by a point at the center of the church structure.
For more information on how to identify a cemetery, check out the “Aerial Photo Interpretation Part 1: Cemeteries” article in our September 2017 Newsletter.
What Address should be given for rural cemeteries?
Many cemeteries do not have addresses, therefore, addresses are not required for cemetery points. In cases where no numbered street address seems to be assigned:
Check out this Q&A for more on cemetery addresses.
Why do we collect information about cemeteries?
The original reason we started collecting information about cemeteries is that they were prominent feature types shown on USGS topographic maps. But another reason is that there are many people that are interested in history and genealogy and find this information useful. One of our volunteers says:
"...as a lifelong genealogist, I have been frustrated with the gap between local information about cemeteries and what is easily available in a consistent, reliable, national format. I have benefited from hundreds of thousands of hours of work by others and this is the way I am giving back."
What is a Post Office?
The United States Postal Service (USPS) is a branch of the federal government that sells postage and delivers mail to the general public. Only official USPS facilities that are staffed with postal service employees and have window service hours for the public should be collected.
Where can I find authoritative lists of Post Offices?
USPS.com’s Find Locations tool is the primary authoritative source for post offices. To limit this list to approved USPS facilities, go to USPS.com’s Find Locations tool, select “Post Offices and Approved Postal Providers” from the Location Types list, click on the Refine search link, and then make sure that only “Post Offices” and “Village Post Offices” are checked.
This restricted definition ensures that the locations that only sell stamps, only have automated postal centers, or only participate in the PO Box Online program (e.g., markets, banks, and office and mailing supply stores) are omitted since they do not qualify as post offices for the National Structures dataset.
Another helpful source is USPS’s Postmaster Finder. If a point is not listed in USPS.com, it may be listed as an RMPO or PTPO on the Postmaster Finder website. This tool is also helpful when searching for discontinued post offices. Be aware that this information is not regularly updated and not all post offices are listed.
Editing/Reviewing Post Offices for a city or county:
If you're interested in reviewing all of the post offices for a city or county, go to the USPS Find Locations web page, restrict the search to “Post Offices” and “Village Post Offices,” type in the city of interest, and select a reasonable search radius. Then go through all of the locations and make sure they are represented in The National Map Corps’ editor. If you are working on a county, then successively type in the names of various cities in that county with a reasonable search radius for each so that when each of your search results are combined you get complete results for the whole county. NOTE: there is a USPS web page for searching for post offices within a county, but this search uses an out-of-date database, so it is recommended not to rely on this county search.
Where do I place a Post Office Structure Point?
Post offices typically occupy one small building. Larger annexes or distribution centers with public post offices may be in larger buildings. The general rule is to locate the post office structure point at the center of the building.
For more information on how to identify a post office, check out the “Aerial Photo Interpretation Part 2: Post Offices” article in our November 2017 Newsletter.
Naming Post Offices:
The preferred way to name a post office is: <Name> + “Post Office” where <Name> is the title listed on the USPS website (e.g., “Pueblo Post Office”). Occasionally, you will see a post office on the USPS website that has a name like “Westminster (Harris Park)”; in this case, name the post office as: "Westminster Post Office Harris Park Station”.
Check out our Name and Address Formatting Guide for more on naming post offices. We also have some Q&A entries that provide more information on how to properly name Community Post Offices (CPOs), Remotely Managed Post Offices (RMPOs), Part Time Post Offices (PTPOs), and Post Office Express locations (POEs).
A City / Town Hall is the primary administrative building of a township or municipal government. City and town halls are usually associated with incorporated places in the U.S. Incorporated places are a legally defined entity and may be called city, borough, town, or village (depending on the state). There are over 19,000 incorporated places in the U.S. as per the Census Bureau's Boundary and Annexation Survey (BAS). There are no incorporated places in Hawaii or Puerto Rico.
Most municipalities or townships have one central city or town hall building. If this is the case, place the point at the center of the building.
Some municipalities may have a municipal “campus” of buildings with administrative offices; others may have individual buildings that are geographically distributed throughout the city. It is important to note that we are not collecting the location of individual city departments. We are only collecting the primary city/town hall (i.e., typically the building that houses the city council and/or mayor’s office). Place the point at the center of this building.
Multiple incorporated places may share a building for their government functions. If so, add a point for each city/town hall. An example of this is the Rye Town Office which occupies space on the Third Floor of the Port Chester Village Hall in Port Chester, NY.
For more information on how to identify a City / Town Hall, check out the “Aerial Photo Interpretation Part 8: City/Town Halls” article in our November 2018 Newsletter.
How do I name a City / Town Hall?
Similar to courthouses, try to determine the name of the building when editing City / Town Hall structures. Common terminology for building names may include City Hall, Town Hall, Village Hall, Municipal Building, Municipal Center, and City Building among others. Contact information on government websites usually includes the building name with the address. Examples include Denver’s City and County Building which houses Denver’s city council, or Cedar Rapids’ City Hall which houses the city manager:
Our Name and Address Formatting Guide has a few additional examples of how to properly format a name for this structure type