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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.  


The Guidelines define School as follows:

A building or building complex used as a learning center for children grades kindergarten through high school.

INCLUDES: Public, private, alternative, and juvenile hall schools. School types include elementary schools, middle schools, high schools, and private K‐12 schools.

DOES NOT INCLUDE: preschools, kindergartens, daycares, or headstart programs.

What is a school? 

The guidelines are quite clear that a school is a building where children are taught in any grade from 1 through 12.

Schools are a challenging structure type because there are so many of them! Every year new ones are opening, and old ones are closing.

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 K-8 or K-12 schools that combine two or more categories into one organization.
Here are some general guidelines for what each school category entails:
  • Elementary School: A school for the beginning years of a child's education, often including kindergarten. Does not include combined elementary and middle schools (e.g., K-8 schools), or K-12 schools. Schools covering grades K-8 or grades K-12 should be categorized as a General School.
  • Middle School: A school between elementary school and high school; grade levels offered will vary between grades 5 through 9.
  • High School: A secondary school attended after middle school that usually goes through grade 12. A high school diploma is offered upon graduation from this type of school.
  • General School: A building or building complex that offers education for children grades kindergarten through high school. Includes schools that do not fall into a specific category, such as K-8 or K-12 schools.

Where can I find authoritative lists of schools?

On this website, look in the Data Sources page for your State to see if volunteers have listed authoritative data sources for schools. 

There are three types of schools: public, charter, and private. Public schools and charter schools are regulated by State Departments of Education, and for this reason there usually are good authoritative lists of these schools on the State Department of Education websites. States are divided up into School Districts, many of which have web pages which are the most authoritative place to look for information.

Private schools are more difficult to sort out because there are no authoritative lists, and they tend to open and close more often than public schools. Here are some non-authoritative places you can look for private school information:
  • State Department of Education websites: these may have lists of  private schools, but in general they are non-authoritative because they may only include non-public schools whose school administrators have requested to be on the list.
  • The National Center for Education Statistics maintains a database of private schools. This database is a result of a voluntary survey that they send out every two years. Their website allows a search for private schools by city, county, or state.
  • The Great Schools website has an online searchable database.
  • The National Association of Independent Schools has an online searchable database.
  • The National Parochial Schools Association lists parochial schools by State.
  • Look on the Data Sources page on this website for your State to see if there are any regional or local sources of private school information

Why does the Structures database contain so many schools that no longer exist?

One original source of information for the Structures database was US Geological Survey topographic maps which were produced from about 1879 to 1992. These maps showed many of the old pioneer schools that were established as a result of the Land Ordinance of 1785. This Act of Congress caused much of the 30 western States to be surveyed and divided into townships six-miles square; in turn each township was divided into 36 numbered square-mile sections, and section No. 16 of each township was to be reserved for a schoolhouse. And many of the resulting one-room schoolhouses still existed and were mapped when the older USGS topo maps were produced.

For volunteers who are history buffs, it can be quite enjoyable to zoom in on these old school locations in the Potlatch editor, and switching over to the Aerial Imagery view, see if any sign is left of these old schools. Sometimes there is a building, sometimes a foundation, and sometimes nothing but a wheat field. A few are still even in use as schools! Those that are no longer in existence or being used as schools should be deleted from the database.

How do I handle schools with many grades?

Many schools, especially rural schools, have K-12 classes 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 at the school website, or, if there is no school website, then at the State Department of Education website. If these websites list separate schools at the same address, then add one structure for each school, which each structure symbol contained within the footprint of the building.


The Guidelines define College and University as follows:

A building or building complex used as an institution of higher learning that grants a degree at the completion of a course of studies.

  • INDICATORS: offers associates degrees or higher.

INCLUDES: 4‐year universities and community colleges, junior colleges requiring a high school diploma or equivalent for admission.

DOES NOT INCLUDE: Technical / trade schools offering technical training for job-specific certifications.


What is a College/University? 

The Guidelines definition of College/University is quite specific, and the key factor is that an institution must grant a degree; there are 4 types of degrees: Associate, Bachelor, Master, and Doctoral. 

Degree-granting generally is regulated by the States, and so each State has a Higher Education Agency which oversees degree-granting institutions. The US Department of Education has a list of these State Higher Education Agencies. These agencies often maintain lists of the degree-granting institutions in their State (refer to the Data Sources pages on this website for each State to find out where to find these lists).

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. An exception is technical colleges which do grant degrees.

A separate issue is accreditation. There are many accreditation organizations which generally are private professional organizations. Each State Higher Education Agency may determine which accreditation organizations have recognized authority within that State. Usually an institution may not grant a degree unless it has been accredited; however there are exceptions to this rule – some States allow religious colleges to grant degrees even if they are not accredited. Conversely, there may be schools that are accredited but do not give out degrees (only certificates).

A second, less obvious stipulation in the definition of College/University, is that there be a building used as an institution of higher learning. This leaves out online universities, unless they teach classes in their buildings as well as online.

Where do I place a College/University structure point?

In general, each college/university campus should be represented by a single structure point placed on the administrative building for that college/university. If one does not have firsthand knowledge of the location of the administration building, it can usually be gleaned from a brief examination of the school's web page. If it cannot be determined where the administration building is located, then place the structure point on a building at the center of the main cluster of buildings on the campus.

A University campus may contain several colleges or schools (ie 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 represented by a single point. 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 at Denver, and the Community College of Denver) – in this case each separate institution should be represented by a point. 

Some Colleges, especially in an urban environment, may have multiple campuses or widely dispersed buildings. This is somewhat of a grey area, but 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 you will have to use your own judgment as to whether it is important enough to be considered a campus and therefore justify a new structure point. 

Medical Schools that are co-located with Hospitals should be represented by a college/university structure point only if the medical school is large enough to have at least one building separate from the Hospital; if so, the associated Hospital would also be represented as a Hospital structure type.

The Guidelines define Fire Stations and EMS Stations as follows:

A building that contains fire‐fighting equipment and personnel or a provider of combined fire‐fighting and rescue services.

  • INDICATORS: houses a fire engine.

INCLUDES: Fire stations with only fire response equipment or with combined emergency medical services operations and/or rescue services.  

DOES NOT INCLUDE: Ambulance stations not part of fire‐fighting services, fire equipment storage facilities, fire hall meeting facilities.

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. It probably has fire personnel visiting it on a regular basis to keep the equipment clean and shiny and ready to go.

Where can I find authoritative lists of  Fire Stations? 

The US Fire Administration has the most complete nationwide list of fire departments. 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 10 years old, some of the informaiton 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 you 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.

The Homefacts website has a list of fire departments by city and county (scroll to the bottom of the page to select a State); but the source of this data is unknown and its accuracy varies.

Refer to the State Data Sources section of this website where additional data sources may be listed for each State. County and city websites also often have information about fire departments; and counties often have an Office of Emergency Management where information can be found.

Fire Department web pages are the best source of data, but may not specify the locations of stations. Stations can generally be recognized in Aerial Imagery or in Street View on Google because the stations have large bays with overhead doors and large concrete pads outside where the engines can park.

How do I name a Fire Station? 

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.
Why are there no authoritative lists of fire/EMS stations? 

It seems surprising that there are no authoritative lists of fire/EMS stations, but this is because historically it has been felt that it is more important that they can find you, rather than for you to find them. They can find you through the 911 system. The 911 system generally is maintained at the county level, where 911 calls are routed to the nearest Public Safety Answering Point (PSAP). While you are talking to a 911 operator at a PSAP, various manual and automated systems are used to pinpoint the location of the call, to find the nearest fire/EMS (or police) station, and to get directions for how to drive to the scene of the call.
However in recent years, with the increased interest in the coordination of responses to public emergencies, there is a recognition that databases of emergency response assets are important to the public and to Offices of Emergency Management at all levels of government.

The Guidelines define Law Enforcement as follows:

A building that houses police stations or sheriffs’ offices.

INCLUDES: Police stations, sheriffs' offices, state troopers or highway patrols.

DOES NOT INCLUDE: Police offices in shopping malls or strip malls, federal law enforcement, park police, school police, railroad police, postal inspectors, locations with administrative functions only.

What is a Law Enforcement structure? 

Law enforcement structures consist of the offices of state troopers, county sheriffs, and city cops. However, if a county sheriffs deputy works out of his house in a rural area, we do not include that location as a structure point (we never capture private residences as structure points).

Where can I find authoritative lists of Law Enforcement structures? 

There are no authoritative lists of Law Enforcement structures.

The closest thing to a national list may be at the USACops website, but it is not clear where this data comes from or how complete it is. There also are lists of police stations at the Homefacts website, but again it is unclear where this data comes from or how complete it is.

The State Data Sources page of this website may have information on lists for your State; in particular, there usually is a State Patrol website which lists the State Patrol troop offices and posts for that State. County and city websites may list law enforcement offices within their boundaries.

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.

The Guidelines define Prison / Correctional Facility as follows:

A building or complex for the confinement of persons convicted of crimes.

  • INDICATORS: medium and maximum security facilities; long-term facilities.

INCLUDES: State or federal prisons, long-term juvenile detention facilities. Jails included only if they have long-term sentences and are a medium or maximum security facility.

DOES NOT INCLUDE: Short‐term holding facilities such as a jail at a police station or court house, sheriff’s department or sheriff’s office, half-way houses, minimum security locations, prison camps or work sites, administrative offices.

What is a Prison/Correctional Facility? 

A Prison/Correctional Facility consists of federal and state prisons and juvenile detention facilities. It is important to note that city and county jails are not included

Where can I find authoritative lists of Prison/Correctional Facilities? 

The authoritative list of Federal prison facilities may be found at the Federal Bureau of Prisons website. Only Institutions, Private Facilities, and Correctional Complexes should be included -- not offices or training centers.

Refer to the State Data Sources pages on this website to find information about data sources for State prisons; in general, each State has a Department of Corrections website which lists private and public prisons in that 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 for each facility. For example, the Florence Federal Correction Complex has three facilities (Florence Federal Correctional Institution, Florence High Security United States Penitentiary, and Florence Administrative Maximum United States Penitentiary), and therefore should have 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 on-line facility map, or, for federal prisons, by examining the photo of the prison entrance on its 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.

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 use the most commonly-used format where the prison name comes last, for example, United States Penitentiary Florence High.

The Guidelines define Hospital / Medical Center as follows:

A building or building complex providing general medical or surgical inpatient care.

  • INDICATORS: Inpatient (overnight) services.

INCLUDES: General hospitals, specialty hospitals (such as children's, cancer, maternity, substance abuse, psychiatric, and rehabilitation hospitals), Veterans Administration hospitals, infirmaries offering inpatient services.

DOES NOT INCLUDE: Psychiatric or behavioral facilities that are not hospitals, long‐term care medical centers or nursing homes, walk-in centers or outpatient clinics, imaging centers, medical doctors' offices, rehabilitation centers.

What is a Hospital/Medical Center? 

A Hospital/Medical Center is a facility which provides inpatient care. In general, these are regulated by State Departments of Health as 
State Licensed and Medicare Certified Hospitals; common hospital types are critical access, general, long-term care, psychiatric and rehabilitation.

Where can I find authoritative lists of Hospital/Medical Centers? 

The US Department of Veterans Affairs maintains an authoritative list of their facilities. Only VA Health Care System and VA Medical Centers should be included.

Refer to the State Data Sources pages on this website for authoritative lists of hospitals in a given State, which are regulated by the State Departments of Health. There are many types of medical facilities, but only those that are listed as Hospitals should be included.

Where should I place a Hospital/Medical Center facility structure point? 

Hospital locations should be placed at the center of the primary building in the medical complex.

The Guidelines define Ambulance Services as follows:

A building used to house ambulances and from which medically-trained staff are dispatched to transport emergency patients and administer emergency medical treatment (en route or at the scene).

INCLUDES: Air ambulance, ground ambulance, ambulances not operated by fire departments but co-housed at a fire station, rescue vehicles not associated with fire departments.

DOES NOT INCLUDE: Ambulance services operated by and housed in a fire station, ambulances for transportation only (not providing medical care), special needs transports, ambulances operated by hospitals/medical centers, ambulance dispatch centers, urgent care centers, freestanding emergency facilities.

What is an Ambulance Service? 

An ambulance service facility is a building that houses a service to transport emergency patients and administer emergency medical treatment but does not include ambulances operated by fire departments.

It is common for non-profit ambulance services to operate out of fire department stations and to be considered as part of the fire department operations -- these facilities are not included as ambulance service facilities (only as Fire Department facilities); generally you can refer to the fire department website to determine the relationship between the two entities. However, non-profit ambulance services may also operate out of their own facilities seperate from fire departments -- these are included as ambulance service facilities.

For-profit ambulance services generally have their own facilities, which should be captured as ambulance service structure points.

Where can I find authoritative lists of Ambulance Services? 

Refer to the State Data Sources pages on this website for state and local lists of ambulance services. Ambulance services generally are licensed by counties, so you may find lists at county websites. State Health Departments also may maintain lists of Ambulance Services.

Do we include air ambulance (helicopters and fixed-wing aircraft) locations as Ambulance Service locations? 

Air ambulances are included as Ambulance Service locations; however it may be difficult to determine where helicopters and fixed-wing aircraft are stationed. Most hospitals have helipads, but these are not home stations for air ambulances. The home stations for air ambulances generally are at airports. State Health Departments may maintain lists of air ambulance services operated within their State.

The Guidelines define Cemetery as follows:

A place or area for burying the dead.

  • INDICATORS: Interments.

INCLUDES: Burial grounds, graves, graveyards, memorial gardens, mausoleums, columbariums, and crypts.

DOES NOT INCLUDE: Graves inundated by lakes or reservoirs, historic cemeteries, unnamed cemeteries and/or graves, funeral homes.

What is a Cemetery? 

The Guidelines definition of a cemetery is straightforward -- it includes places where the dead are buried. The human dead anyway -- pet cemeteries are not included. It addition to the types of features mentioned in the Guidelines, columbariums (a place for the storage of urns containing cremated remains) are also included.

Some small family cemeteries (usually historical) are included in the database, but in general more recent family cemeteries are not included. Single graves also are generally not included, unless they are the graves of famous historical figures.
Where does our Cemetery database originate?

There are two principal sources of cemetery data in the TNMC Structures database: US Geological Survey Topographic maps, and the USGenWeb project.

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. If you are viewing a listed cemetery location in the Aerial Imagery view of the Potlatch editor, and there doesn't seem to be anything visible there, try switching over from aerial imagery to USGS Topos, and then you often will see the notation of a cemetery on the topographic map.

Additional cemetery locations were submitted to the database by the USGenWeb Project. This volunteer project, started in 1996, fosters Internet resources for genealogical research in every county and every state of the United States.

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.

Where should I place a cemetery structure point?

The general rule is to locate the cemetery structure point at the centroid of the cemetery area. A single point should be placed even if a cemetery has a combination of facilities (graves, mauseleums, 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.

What are authoritative sources of information about cemetery locations?

There are no single complete authoritative sources of information about cemeteries, but there are many internet resources that together can provide a fairly complete list of cemeteries:
  • The Find A Grave website has a quite comprehensive list; you can search for cemeteries by name or county. The website gives latitude and longitude for most cemeteries.
  • The has a smaller list which can be searched by county.
  • The BillionGraves website has coordinates for cemeteries in its database, and shows the location of the cemetery on aerial imagery. You can search their database by county.
  • The USGenWeb Project archives list cemeteries by State and County. It also has cemetery lists as part of its Tombstone Transcription Project.
  • The Churches and Cemeteries website lists cemeteries by State and County.
  • Check the Data Sources page for your State on this website -- there may be local resources with cemetery locations.

What Address should be given for rural cemeteries?

Many cemeteries are located in rural areas where county and state roads do not have precise mailing addresses. You can attempt to find an address through reverse geocoding in Google Maps Classic: 
  1. Locate the cemetery on Google Maps Classic.
  2. Right-click on the road at the cemetery entrance and select "What's Here?"
  3. In the search box, Google Maps will show the latitude/longitude of the point where you clicked.
  4. In the left pane of the map window, Google will show the best mailing address it could come up with using its reverse-geocoding service. If it cannot come up with an address, it still will show the name of the nearest street, and the city and zipcode of the location.
In cases where no numbered street address seems to be assigned:
  1. If there is a road intersection nearby, put in the road names, for example, "County Road 10 and US Highway 20".
  2. If there is only a single road nearby, use only the name of the nearest road, for example, "County Road 10".
  3. If no road is nearby, leave the Address blank, and fill in only the nearest city (and zipcode, if you know it).

Why do we collect information about cemeteries?

Perhaps 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:

" 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."

The Guidelines define Post Office as follows:

An official facility of the U.S. Postal Service used for processing and distributing mail and other postal material.

  • INDICATORS: Official logo of U.S. Post Office.

INCLUDES: USPS official post offices, post office stations, branch post offices, community post offices (CPOs), village post offices (VPOs), and postal annexes with a public post office.

DOES NOT INCLUDE: Mail drop off locations (blue US Mail box), carrier annexes with no public hours, or contract postal units (CPUs, which are often in commercial establishments) that do not have their own zip code.

What is a Post Office? 

There are quite a few types of Location Types you can choose from, but the USGS guidelines stipulate that only official USPS facilities should be included in the National Structures dataset: this translates to the Post office, Village Post office, and Contract Postal Units location types. To do a search for these three types, select “Post Offices and Approved Postal Providers” from the Location Types list and then click on the Refine search link, and then make sure that only Post Offices, Village Post offices, and Contract Postal Units are checked.

This restricted definition means that many locations that sell stamps or have only automated postal centers or only participate in the PO Box Online program, such as markets, banks, and office and mailing supply stores, do not qualify as Post Offices for the National Structures dataset.

Naming Post Offices: 
The guidelines stipulate that the correct way to name a post office is: <name> Post Office, for example “Pueblo Post Office”. Also, to naming the Contract Postal Unit, the correct way is: Name+Contract Postal Unit or Name+CPU. The name is the name that is shown in the USPS website. 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”. .

Editing/Reviewing Post Offices for a city or county

You might want to review all of the Post Offices for a city or county. To do this, go to the USPS Find Locations web page; restrict the search to Post Offices and Village Post Offices, and Contract Postal Units; type in the city of interest; and select a reasonable search radius. Then go through all of the locations and make sure they are in the Structures database. 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.

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