Following some basic definitions of words and acronyms which can be found on elevation certificates, survey plats and our website.  Please note the the following contents are strictly for informative purposes and have no legal value.  Some of the information may be difficult to understand, however, we’d be happy to explain. Please do not hesitate to contact us.

Definitions

ALTA/ACSM Surveys: (American Land Title Association/American Congress on Surveying and Mapping)
Usually referred to as ALTA Surveys, these surveys are usually more commonly performed on commercial and industrial properties. They determine property lines, locate substantial visible improvements, and typically identify and show, utilities, parking spaces, building dimensions, information on identifying adjoining property, property zoning information and flood zones as listed on the “Table A” options from the ALTA requirements. An ALTA Survey is usually performed in coordination with the issuance of a Title Insurance Policy on the property by a Title Insurance Company and requires easements and other restrictions contained with in the title commitment to be addressed on the survey. An ALTA Survey is a very comprehensive survey.

BFE: This stands for Base Flood Elevation. It is the elevation shown on the Flood Insurance Rate Map (FIRM) for Special Flood Hazard Areas (Zones AE, AH, A1-A30, AR, AR/A, AR/AE, AR/A1-A30, AR/AH, AR/AO, V1-V30, and VE )that indicates the water surface elevation resulting from a flood that has a one percent chance of equaling or exceeding that level in any given year.

Benchmark: A surveyor's mark on a stationary object of predetermined position and/or elevation used as a reference point for surveys and/or elevations. It is a standard by which something can be measured. A Construction Benchmark is frequently necessary to obtain a permit for construction of a structure.

CAD: CAD stands for Computer Aided Drafting. In short it is the use of a computer and software to accurately draw objects to scale and print copies of the drawing. It is used to design/draw detailed two- or three-dimensional objects, such as mechanical parts or buildings. Mandle-Edwards Surveying, Inc. uses CAD to prepare its survey plats.

CD: This stands for Cairo Datum and was originally based on a benchmark at an Army Corps of Engineers facility in Cairo Illinois. In 1879 an elevation survey was conducted down the Mississippi River from Cairo to New Orleans. The elevation of the Cairo benchmark was arbitrarly raised to ensure there would be no negative elevations in the New Orleans area. The difference between the elevation from Cairo and the Mean Sea Level at the time was found to be 20.43 feet. The Cairo Datum currently used in the New Orleans area is just an artificial means for keeping the elevations positive, hence making mathematic calculations easier.

Curb Elevation: The elevation of the top of the curb of the street. Some municipalities require that new construction be constructed a minimum height above the top of the curb.

Datum: any level surface, line, or point used as a reference in measuring elevations

Easement: The right to use the real property of another for a specific purpose. The easement is itself a real property interest, but legal title to the underlying land is retained by the original owner for all other purposes. Typical easements are for access to another property (often redundantly stated "access and egress," since entry and exit are over the same path), for utility or sewer lines both under and above ground, use of spring water, entry to make repairs on a fence or slide area, drive cattle across and other uses.

Elevation: The distance of any point above or below a reference level (datum).

Elevation Certificate: A document or form used to report the findings of an elevation survey. Frequently the document is a FEMA certificate that is used to provide necessary information to the National Flood Insurance Program and insurance agent for the purpose of determining the proper Flood Insurance premium.

Encroachment: Any object which crosses from one property on to another property.

FIRM: The Flood Insurance Rate Map is the official map on which FEMA has depicted both the special hazard areas and the risk premium zones applicable to the community. Information from these maps is reported on the FEMA Elevation Certificate, along with data from a Flood Elevation Survey, to determine the proper premium for Flood Insurance.

Floodplain: According to FEMA, any land area susceptible to being inundated by flood waters from any source.

Flood Zones: Geographic areas defined by FEMA according to varying levels of flood risk. These zones are depicted on a community's Flood Hazard Boundary Map or a Flood Insurance Rate Map (FIRM).

Flood Zones that begin with "A": Special Flood Hazard Areas. These are high-risk zones and have a 1% annual chance of flooding and a 26% chance of flooding over the life of a 30-year mortgage. These zones have a Base Flood Elevation that is the minimum elevation to which FEMA requires new construction be built. Local governments may require a higher minimum elevation for new construction.

Flood Zones "B", “C” or "X": Lower-risk flood zones that have less than a 1% annual chance of flooding. No base flood elevations or depths have been established for these zones. Sometimes the areas in these Flood Zones are incorrectly referred to as not being in a Flood Zone. After experiencing Hurricane Katrina, we all know that flooding can occur almost everywhere in New Orleans.

Mandle-Edwards Surveying, Inc. recommends flood insurance properties located in all Flood Zones.

GPS: This stands for Global Positioning System and allows high accuracy measurements to be made over long distances with the reception of signals from satellites. Using a permanent stationary GPS receiver (Base Station), a wireless internet connection, a mobile GPS receiver (Rover) and data collected from satellites orbiting Earth, a surveyor can accurately determine his horizontal and vertical position on the ground.

Geodetics: The science of dealing with the investigation of scientific questions connected with the shape and dimensions of the Earth. That branch of Surveying that into account the curvature of the Earth to determine a position.

Highest Adjacent Grade: (HAG) The highest elevation of the ground surface next to the building.

Legal Description: Also called a Property Description, is a written document that describes a piece of property. It most frequently include the dimensions of the property, the distance to the nearest corner, the bounding streets, the subdivision name, the district or parish, the square, the lot number or letter, and other useful information.

Lowest Adjacent Grade: (LAG) The lowest elevation of the ground surface next to the building.

NAVD 88: The North American Vertical Datum of 1988 (NAVD 88) is the vertical control datum established in 1991 by the minimum-constraint adjustment of the Canadian-Mexican-U.S. leveling observations. It held fixed the height of the primary tidal bench mark, referenced to the new International Great Lakes Datum of 1985 local mean sea level height value, at Father Point/Rimouski, Quebec, Canada. Additional tidal bench mark elevations were not used due to the demonstrated variations in sea surface topography, i.e., the fact that mean sea level is not the same equipotential surface at all tidal bench marks. ("Results of the General Adjustment of the North American Datum of 1988," Surveying and Land Information Systems Vol. 52, No. 3, 1992 pp. 133-149)

NGVD 29: "The National Geodetic Vertical Datum of 1929: The name, after May 10, 1973, of (the) Sea Level Datum of 1929." (Geodetic Glossary, pp. 57)
"Datum vertical control datum established for vertical control in the United States by the general adjustment of 1929."
"Mean sea level was held fixed at the sites of 26 tide gauges, 21 in the U.S.A. and 5 in Canada. The datum is defined by the observed heights of mean sea level at the 26 tide gauges and by the set of elevations of all bench marks resulting from the adjustment. A total of 106,724 km of leveling was involved, constituting 246 closed circuits and 25 circuits at sea level."

Parcel: A distinct, contiguous portion or tract of land.

Plat: A survey drawing.

Right of Way: A strip of land dedicated usually for transportation usage such as a highway or railroad. Utility lines may also have a dedicated right of way.

Servitude: See Easement above.

Surveying: Land Surveying is the science, technique and art of determining the location of property boundaries by observation and measurement of linear and angular distances with the use of mathematics, geometry and trigonometry in accordance with land documentation and legal standards.

Topographic Survey: Commonly called a Topo Survey, this type of survey is frequently used by Architects, Engineers and Developers for the design and development of property. Typically a Topo Survey will show the boundaries, buildings, improvements, known easements, encroachments as well as any significant natural features on a property. Surface elevations on a specified interval, elevations along the perimeter of pavement and elevations on sewer and drainage features with the inverted elevations of and the size of the sewer and drain pipes are a frequent component of a Topo Survey.

Topographic Map: Topographic maps show the natural and cultural features of a portion of land. Natural features commonly include contour lines, hydrography vegetation. Cultural features usually include roads, buildings, bridges, political boundaries, and Township, Range and Section divisions of the land. Topographic maps are used by a wide variety of people, such as surveyors laying out a new road; backpackers finding their way into remote areas; scientists describing soil or vegetation types, wildlife habitat, or hydrology and military personnel planning field operation