Glossary

I’m not usually one to play the semantics game or argue over for the strict application of language and terminology, that ends up far too often being an exercise in us trying to define words. However, It is occasionally necessary to nit-pick, and so at those times I come here; to this glossary from a man with a tenuous grasp on English in general.

Sources: “FEMA Directory” (n.d.)

Common

Surface ancroyms

• A DEM (Digital Elevation Model) Represents the bare-Earth surface, removing all natural and built features;
• A DTM (Digital Terrain Model) typically augments a DEM, by including vector features of the natural terrain, such as rivers and ridges. A DTM may be interpolated to generate a DEM, but not vice versa.
• DSM (Digital Surface Model) is a model that is intended to represent the bare-Earth and all of its above-ground features.
• REM - (Relative Elevation Model)s reorganize space in relation to a feature.
• HAND is the Height above nearest drainage, a REM relative to a drainage network.

Words you might encounter that are interrelated:

Hydrology is the study of the cycling of the mass of water across the landscape, hydraulics is the study of how we can transform the instantaneous state of that cycle into an elevation, and flood inundation mapping is the act of placing geographic context on those calculations.

Alluvial: Alluvial refers to sediment type created by running water. Particles often appear visibly rounded. That running water is typically found in…
Fluvial: “of or found in a river”, if you can point to a body of water, that is likely fluvial as opposed to…
Pluvial (flooding): is flooding independent of a source of water.
From the standpoint of precipitation, that water can mechanically get to a location in two ways. The first…

1. Infiltration excess: is when the rate of rainfall exceeds the rate at which water can infiltrate the soil column
   
2. Saturation excess: is when added rain can not infiltrate the soil because all void space is filled.

Both tend to generate Hortonian overland flow, often modeled as lateral inflow.

Modeling terms

There’s not really a difference between irreproducible, unreproducible, and non-reproducible?

There’s not a right way to phrase irreplicable / unreplicable, but it’s not unrelicatable.

I am of the opinion most incorrectly apply capitalization to LIDAR. LiDAR is a company, not a technique, like RADAR, and is most commonly called radar. Deering and Stoker (2014)

I model and color, no extra “l”’s and “u”’s; we won that debate in 1776.

Words I am trying to learn:

• No
• Schedule, in spelling and spirit
• summary, not summery the season
• aerial imagery vs areal areas
• Propose a purpose
• Whether or not the weather is nice
• The historical record has many historic floods
• publicly, not publically

Acronyms

Organizations and programs

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Acronym	Longform	Definition
AASHTO	American Association of State Highway and Transportation Officials
AREMA	American Railroad Engineering and Maintenance-of-Way Association
CIROH	Cooperative Institute for Research to Operations In Hydrology
CISESS	Cooperative Institute for Satellite Earth System Sensing
CUAHSI	Consortium of Universities for the Advancement of Hydrologic Science, Inc.
ESRI	Environmental Systems Research Institute
FEMA	Federal Emergency Management Agency	The independent Federal agency that, among many other responsibilities, oversees the administration of the National Flood Insurance Program.
FEMA	Federal Emergency Management Agency
FHWA	Federal Highway Administration
FIMA	Federal Insurance and Mitigation Administration	The component of FEMA that has direct responsibility for administering the National Flood Insurance Program.
HEC	Hydraulic Engineering Circular
ISO	International Organization for Standardization
JALBTCX	Joint Airborne Lidar Bathymetry Technical Center of Expertise
NGS	National Geodetic Survey
NHI	National Highway Institute
NOAA	National Oceanic and Atmospheric Administration
NRC	National Research Council
NWS	National Weather Service
OWP	Office of Water Prediction
TIGER	Topologically Integrated Geographic Encoding and Referencing System	The nationwide digital database of planimetric base map features developed by the U.S. Bureau of the Census for the 1990 Census.
UK	United Kingdom
US	United States
USACE	US Army Corps of Engineers
USDA	US Department of Agriculture
USGS	US Geological Survey
CRESIS	Center for the Remote Sensing of Ice Sheets
Inc.	Incorporated
NASA	National Association of Silly Acronyms
NOAA	National Organization for the Advancement of Acronyms

FIM related

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Acronym	Longform	Definition
	500-Year Flood	See 0.2-Percent-Annual-Chance Flood
	50-Year Flood	See 2-Percent-Annual-Chance Flood.
	Ordinance Level A	Per 44 CFR 60.3 (a), this ordinance level occurs when the Administrator has not defined the special flood hazard areas within a community, has not provided water surface elevation data, and has not provided sufficient data to identify the floodway or coastal high hazard are, but the community has indicated the presence of such hazards by submitting an application to participate in the Program.
	Ordinance Level B	Per 44 CFR 60.3 (b), this ordinance level occurs when the Administrator has designated areas of special flood hazards (A zones) by the publication of a community’s FHBM or FIRM, but has neither produced water suface elevation data nor identified a floodway or coastal high hazard area.
	Ordinance Level C	Per 44 CFR 60.3 (c), this ordinance level occurs when the Administrator has provided a notice of final flood elevations for one or more special flood hazard areas on the community’s FIRM and, if appropriate, has designated other special flood hazard areas without base flood elevations on the community’s FIRM, but has not identified a regulatory floodway or coastal high hazard area.
	Ordinance Level D	Per 44 CFR 60.3 (d), this ordinance level occurs when the Administrator has provided a notice of final flood elevations within Zones A1-30 and/or AE on the community’s FIRM and, if appropriate, has designated AO zones, AH zones, A99 zones, and A zones on the community’s FIRM, and has provided data from which the community shall designate its regulatory floodway.
	Ordinance Level E	Per 44 CFR 60.3 (e), this ordinance level occurs when the Administrator has provided a notice of final base flood elevations within Znes A1-30 and/or AE on the community’s FIRM and, if appropriate, has designated AH zones, AO zones, A99 zones, and A zones on the community’s FIRM, and has identified on the community’s FIRM coastal high hazard areas by designating Zones V1-30, and/or V.
	Unnumbered A Zone	Flood insurance rate zones, designated “Zone A” on a FIRM, that are based on approximate studies.
	zonal classification	Classification based data set value (ranges) and/or material properties or other attributes specified for polygonal regions as is common with GIS products.
SFHA	Special Flood Hazard Area	The area delineated on a National Flood Insurance Program map as being subject to inundation by the base flood. SFHAs are determined using statistical analyses of records of riverflow, storm tides, and rainfall; information obtained through consultation with a community; floodplain topographic surveys; and hydrologic and hydraulic analyses.
SOMA	Summary of Map Actions	A list, generated by FEMA and delivered to the community, that summarizes the LOMAs, LOMR-Fs, and LOMRs that are or will be affected by a physical update to a FIRM.
SOMA Category 1	SOMA Category 1 - LOMRs and LOMAs Incorporated	The modifications effected by the LOMRs and LOMAs have been reflected on the Preliminary copies of the revised FIRM panels. However, these LOMRs and LOMAs will remain in effect until the revised FIRM becomes effective.
SOMA Category 2	SOMA Category 2 - LOMRs and LOMAs Not Incorporated (Revalidated)	The modifications effected by the LOMRs and LOMAs have not been reflected on the Preliminary copies of the revised FIRM panels because of scale limitations or because the LOMR or LOMA issued had determined that the lot(s) or structure(s) involved were outside the Special Flood Hazard Area, as shown on the FIRM. These LOMRs and LOMAs will be revalidated free of charge 1 day after the revised FIRM becomes effective through a single letter that reaffirms the validity of the previous LOMC.
SOMA Category 3	SOMA Category 3 - LOMRs and LOMAs Superseded	The modifications effected by the LOMRs and LOMAs have not been reflected on the Preliminary copies of the revised FIRM panels because they are being superseded by new detailed flood hazard information or the information available was not sufficient to make a determination. These LOMRs and LOMAs will no longer be in effect when the revised FIRM becomes effective.
SOMA Category 4	SOMA Category 4 - LOMRs and LOMAs To Be Redetermined	The LOMCs in Category 2 will be revalidated through a single letter that reaffirms the validity of the determination in the previously issued LOMC. For LOMCs issued for multiple lots or structures where the determination for one or more of the lots or structures has changed, the LOMC cannot be revalidated through this administrative process. The NSP will review the data previously submitted for the LOMR or LOMA request and issue a new determination for the affected properties after the effective date of the revised FIRM.
Zone A		The flood insurance rate zone that corresponds to the 100-year floodplains that are determined in the FIS by approximate methods. Because detailed hydraulic analyses are not performed for such areas, no base flood elevations or depths are shown within this zone.
Zone A99		The flood insurance rate zone that corresponds to areas of the 100-year floodplain what will be protected by a Federal flood protection system where construction has reached specified statutory milestones. No base flood elevations or depths are shown within this zone.
Zone AE		The flood insurance rate zone that corresponds to the 100-year floodplains that are determined in the FIS by detailed methods. In most instances, whole-foot base flood elevations derived from the detailed hydraulic analyses are shown at selected intervals within this zone.
Zone AH		The flood insurance rate zone that corresponds to the 100-year shallow flooding (usually areas of ponding) where average depths are between 1 and 3 feet. Whole-foot base flood elevations are derived from detailed hydraulic analyses are shown at selected intervals within this zone.
Zone AO		The flood insurance rate zone that corresponds to the 100-year shallow flooding ( usually sheet flow on sloping terrain) where average depths are between 1 and 3 feet. Average whole-foot depths derived from the detailed hydraulic analyses. The highest top of curb elevation adjacent to the lowest adjacent grade (LAG) must be submitted if the request lies within this zone.
Zone AR		Zone AR is the flood insurance rate zone used to depict areas protected from flood hazards by flood control structures, such as a levee, that are being restored. FEMA will consider using the Zone AR designation for a community if the flood protection system has been deemed restorable by a Federal agency in consultation with a local project sponsor; a minimum level of flood protection is still provided to the community by the system; and restoration of the flood protection system is scheduled to begin within a designated time period and in accordance with a progress plan negotiated between the community and FEMA. Mandatory purchase requirements for flood insurance will apply in Zone AR, but the rate will not exceed the rate for unnumbered A zones if the structure is built in compliance with Zone AR floodplain management regulations. For floodplain management in Zone AR areas, elevation is not required for improvements to existing structures. However, for new construction, the structure must be elevated (or floodproofed for non-residential structures) such that the lowest floor, including basement, is a maximum of 3 feet above the highest adjacent existing grade if the depth of the base flood elevation (BFE) does not exceed 5 feet at the proposed development site. For infill sites, rehabilitation of existing structures, or redevelopment of previously developed areas, there is a 3 foot elevation requirement regardless of the depth of the BFE at the project site. The Zone AR designation will be removed and the restored flood control system shown as providing protection from the 1% annual chance flood on the NFIP map upon completion of the restoration project and submittal of all the necessary data to FEMA.
Zone D		The flood insurance rate zone that corresponds to unstudied areas where flood hazards are undetermined but possible.
Zone Gutter		Boundary, shown on a Flood Insurance Rate Map, dividing Special Flood Hazard Areas of different Base Flood Elevations, base flood depths, flood velocities, or flood insurance risk zone designations.
Zone V		The flood insurance rate zone that corresponds to the 100-year costal floodplains that have additional hazards associated with storm waves. Because approximate hydraulic analyses are performed for such areas, no base flood elevations (BFEs) are shown within this zone. Mandatory flood insurance purchase requirements apply.
Zone VE		Zone VE is the flood insurance rate zone that corresponds to the 100-year coastal floodplains that have additional hazards associated with storm waves. BFEs derived from the detailed hydraulic analyses are shown at selected intervals within this zone. Mandatory flood insurance purchase requirements apply.
Zone X		The flood insurance rate zone that corresponds to areas outside the 500-year floodplain, areas within the 500- year floodplain, and areas of 100-year flooding where average depths are less than 1 foot, areas of 100-year flooding where the contributing drainage area is less than 1 square mile, and areas protected from 100-year flood by levees. No base flood elevations or depths are shown within this zone.
Zone X (shaded and unshaded) B, and C		Are the flood insurance rate zones that corresponds to areas outside the 500-year floodplain, areas within the 500- year floodplain, and areas of 100-year flooding where average depths are less than 1 foot, areas of 100-year flooding where the contributing drainage area is less than 1 square mile, and areas protected from 100-year flood by levees. No base flood elevations or depths are shown within these zones.

Technical terms

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Acronym	Longform	Definition
	Bit	An abbreviation for binary digit, a number that can have only a value of 0 or 1.
	Byte	A group of bits that can be stored and retrieved as a unit.
	Kilobyte	A unit of memory representing 1,024 bytes and often designated with the symbol K, as 4Kb or 4 kilobytes. The symbol K is also used to refer to 1,024 words of any specified size.
	Hypervisor	the software that runs virtual machines, typically sits between hardware and software (contrasted with docker, which is software only)
	Micro service	software is composed of small independent services that communicate over well-defined APIs.
HPC	High Performance Computing
PC	Personal Computer
REST API	Representational State Transfer Application Programming Interface	REST stands for Representational State Transfer. REST defines a set of functions like GET, PUT, DELETE, etc. that clients can use to access server data. Clients and servers exchange data using HTTP.
ASCII	American Standard Code for Information Interchange	A popular standard for the exchange of alphanumeric data.
MatLab		Desktop program that expresses matrix and array mathematics directly
CSV	comma-separated values
DIM	Dense Image Matching
ECW	Enhanced Compression Wavelet
JPEG	oint Photographic Experts Group	commonly used method of lossy compression for digital images
LAS		an industry-standard binary format for storing lidar data
LIDAR	Light Detection and Ranging	An aerial survey method that illuminates the target with pulsed laser light and measures the reflected pulses.
MrSID		image, multiresolution seamless image database
NED	National Elevation Dataset
PNG	Portable Network Graphics
SIF	Standard Interchange Format	A commonly used format for the exchange of alphanumeric data.
TIFF	Tagged Image File Format
TIN	Triangulated Irregular Network	A set of non-overlapping triangles developed from irregularly spaced points that is used to represent the facets of a surface.
VPF	Vector Product Format	A standard format, structure, and organization, used by National Imagery and Mapping Agency, for large geographic databases that are based on a georelational data model and are intended for direct use. VPF is designed to be compatible with a wide variety of applications and products. VPF uses tables and indexes that permit direct access by spatial location and thematic content and is designed to be used with any digital geographic data in vector format that can be represented using nodes, edges, and faces. VPF defines the format of data objects, and the georelational data model provides a data organization within which software can manipulate the VPF data objects.
flt	float grid file
	Aperture	words
API	Application Programming interface
CAD	Computer-Aided Design
CEO	Chief Executive Officer	The official of a community who has the authority to implement and administer laws, ordinances, and regulations for that community.
CPU	Central Processing Unit
PO	Project Officer	A FEMA staff member in the Regional Office or in Headquarters who performs contract monitoring functions, which include providing technical direction to FEMA contractors, monitoring the progress of contractors’ work, and evaluating contractor performance.
	Choropleth Map	A map with shaded or hatched areas. (Choro = place and pleth = value.)
	interferometric	Techniques in which electromagnetic waves are superimposed, causing the phenomenon of interference in order to extract information.
	photogrammetry	The science of making measurements from photographs, especially for recovering the exact positions of surface points.
ADCP	Acoustic Doppler Current Profiler
ADP	Acoustic Doppler Profiler
CFD	Computational Fluid Dynamics
CFL	Courant-Friedrichs-Lewy
IFSAR	Interferometric Synthetic Aperture Radar
LIDAR System	Light Detection and Ranging System	An airborne laser system, flown aboard rotary or fixed-wing aircraft, that is used to acquire x, y, and z coordinates of terrain and terrain features that are both manmade and naturally occurring. LIDAR systems consist of an airborne Global Positioning System with attendant base station(s), Inertial Measuring Unit, and light-emitting scanning laser.

Alphabetical

Searchable

Catagorically grouped

References

Deering, Carol A., and Jason M. Stoker. 2014. “Let’s Agree on the Casing of Lidar” 4 (6).

“FEMA Directory.” n.d. https://hazards.fema.gov/femaportal/wps/portal/!ut/p/z0/04_Sj9CPykssy0xPLMnMz0vMAfIjo8zifQI83D38vQ38DdyCLQ0CnY1djAN9TY0NzAz0C7IdFQHJLwc3/. Accessed March 6, 2024.