Law Enforcement Structures

This feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Geological Survey (USGS), displays police and prison landmarks in the U.S. Per the USGS, "Structures data are designed to be used in general mapping and in the analysis of structure related activities using geographic information system technology. The National Map structures data is commonly combined with other data themes, such as boundaries, elevation, hydrography, and transportation, to produce general reference base maps. The types of structures collected are largely determined by the needs of disaster planning and emergency response, and homeland security organizations."

This feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Census Bureau, displays ZIP Code Tabulation Areas. Per the USCB,
“ZIP Code Tabulation Areas (ZCTAs) are approximate area representations of U.S.
Postal Service (USPS) ZIP Code service areas that the Census Bureau creates to
present statistical data for each decennial census. Data users should not use
ZCTAs to identify the official USPS ZIP Code for mail delivery. The USPS makes periodic changes to ZIP Codes to support more efficient mail delivery.”

This image layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Forest Service (USFS), displays the fire regime groups from the Landfire project. Per USFS, "The Fire Regime Groups characterize the
presumed historical fire regimes within landscapes based on interactions
between vegetation dynamics, fire spread, fire effects, and spatial
context."

Fire Regime Groups are defined as:

• I: 0 to 35 year frequency, low to mixed severity 
• II: 0 to 35 year frequency, replacement severity 
• III: 35 to 200 year frequency, low to mixed severity 
• IV: 35 to 200 year frequency, replacement severity 
• V: 200+ year frequency, any severity 
• Indeterminate Regime: No defined fire behavior or extremely low probability of ignition

Data currency: Current federal service

Law Enforcement Structures

This feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Geological Survey (USGS), displays police and prison landmarks in the U.S. Per the USGS, "Structures data are designed to be used in general mapping and in the analysis of structure related activities using geographic information system technology. The National Map structures data is commonly combined with other data themes, such as boundaries, elevation, hydrography, and transportation, to produce general reference base maps. The types of structures collected are largely determined by the needs of disaster planning and emergency response, and homeland security organizations."

State Legislative Districts - Upper Houses

This feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Census Bureau (USCB), displays State Legislative Districts (SLDs) in the upper houses of state legislatures in the United States.  According to the USCB, "SLDs are the areas from which members are elected to state legislatures. They embody the upper (senate) and lower (house) chambers of a state legislature. Nebraska has a unicameral legislature and the District of Columbia has a single council, both of which the Census Bureau treats as upper-chamber legislative areas for data presentation; there are no data by lower houses for either Nebraska or the District of Columbia".

Law Enforcement Structures

This feature layer, utilizing National Geospatial Data Asset (NGDA) data from the U.S. Geological Survey (USGS), displays police and prison landmarks in the U.S. Per the USGS, "Structures data are designed to be used in general mapping and in the analysis of structure related activities using geographic information system technology. The National Map structures data is commonly combined with other data themes, such as boundaries, elevation, hydrography, and transportation, to produce general reference base maps. The types of structures collected are largely determined by the needs of disaster planning and emergency response, and homeland security organizations."

National Inventory of Dams

The NID does not yet contain all dams in the U.S. that meet these criteria. Continued, routine updates to the NID and enhanced data collection efforts, focused on the most reliable data sources (primarily the many federal and state government dam regulatory programs), will help capture these dams and result in a more robust dataset over time."

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