The information in this package has been assembled for the use of the City of Boca Raton. No degree or order of accuracy has been assigned to data in this package. Although this package has been prepared from the best available information, the City of Boca Raton assumes no responsibility for the accuracy or completeness of the information or any errors or omission and makes no warranties, express or implied, concerning accuracy, completeness, reliability or suitability of this data. This data should not be relied upon as the sole basis for solving a problem whose incorrect solution could result in injury to person or property.
Elevations must be verified consistent with procedures established by Chapter
472 Florida Statutes "Land Surveying and Mapping" and the Florida Administrative
Code Chapter 61617-6 "Minimum Technical Standards".
The reference map shows the approximate location of each numbered bench mark.
FIRST EDITION – April 2003
The following map and information has been made available for anyone interested (in particular the surveying, engineering, mapping and construction community) to simplify the process of locating and obtaining information about available bench marks within the City of Boca Raton.
A bench mark is a relatively permanent material object, natural or artificial, bearing a marked point whose elevation above or below an adopted datum is known. Common examples of bench marks are metal disks set in concrete or a corner of a concrete headwall or sidewalk. An elevation is defined as the vertical distance, along a line that follows the direction of gravity as indicated by a plumb line, from a datum to a point or object.
The datum used by the City of Boca Raton Engineering Division – Survey Section is the National Geodetic Vertical Datum of 1929 (NGVD 29’). This datum is a nationwide reference surface for elevations throughout the United States generated by the National Geodetic Survey (NGS). NGVD 29 was established by leveling between 26 tidal stations located along the coasts of the United States and Canada. Leveling is the process of determining elevations of points or their difference in elevation. A tidal station is the geographic location at which tidal observations are conducted. The year 1929 indicates the year when all the field-leveling observations were finally adjusted by the National Geodetic Survey (NGS).
NGVD 29 is a fixed datum and does not take into account the changing stands of sea level. Because there are many variables affecting sea level, and because this datum is a best fit over such a broad area, the relationship between the NGVD 29 datum and local mean sea level is not consistent from one location to another in either time or space. For this reason, the National Geodetic Vertical Datum of 1929 (NGVD 29’) should not be confused with mean sea level.