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Virginia Administrative Code (Last Updated: January 10, 2017) |
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Title 18. Professional and Occupational Licensing |
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Agency 10. Board for Architects, Professional Engineers, Land Surveyors, Certified Interior Designers and Landscape Architects |
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Chapter 20. |
Section 382. Minimum standards and procedures for surveys determining topography; field procedures; office procedures
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A. The minimum standards and procedures set forth in this section are to be used for topographic surveys performed in the Commonwealth of Virginia pursuant to Chapter 4 (§ 54.1-400 et seq.) of Title 54.1 of the Code of Virginia. The application of the professional's seal, signature, and date as required by these regulations shall be evidence that the topographic survey is correct to the best of the professional's knowledge and belief and complies with the minimum standards and procedures.
B. Minimum field and office procedures. The following information shall be shown on, or contained in, all plats, maps, or digital geospatial data including metadata used to depict the results of the topographic survey:
1. Physical improvements on the property, all man-made or installed structures, as well as visible evidence of underground features (such as manholes, catch basins, telephone pedestals, power transformers, etc.), and utility lines and poles shall be shown or depicted when they are visible based on the methodology and scale. If the methodology or scale prevents depiction of the above, then notice shall be clearly stated on or contained in the map, plat, or digital geospatial data including metadata indicating the improvements that are not depicted.
2. Elevations shall be provided as spot elevations, contours, or digital terrain models.
3. Onsite, or in close proximity, bench mark(s) shall be established with reference to vertical datum, preferably North American Vertical Datum (NAVD), and shown in the correct location.
4. The title of the topographic survey identifying the land surveyed and showing the state, county or city in which property is located.
5. Name of the individual or entity for whom the survey is being performed.
6. Date, graphic scale, numerical scale, and contour interval of plat, map, or digital geospatial data including metadata.
7. North arrow and source of meridian used for the survey.
8. Names of highways, streets and named waterways shall be shown.
9. The horizontal and vertical unit of measurement, coordinate system, and data, including adjustments if applicable.
10. A statement, in the following form, shall be shown on or contained in plats, maps, or digital geospatial data including metadata:
This ________________ (provide description of the project) was completed under the direct and responsible charge of _______________________________ (Name of Professional) from an actual Ground or Airborne (check the one that is applicable) survey made under my supervision; that the imagery and/or original data was obtained on ______________ (Date); and that this plat, map, or digital geospatial data including metadata meets minimum accuracy standards unless otherwise noted.
C. Minimum positional accuracies shall be met in accordance with the tables in subdivisions 1, 2, and 3 of this subsection. These tables are not intended to be acceptable in all situations, and the professional shall be responsible to perform the work to the appropriate quality and extent that is prudent or warranted under the existing field conditions and circumstances. Metric or other unit of measurements shall meet an equivalent positional accuracy. Map or plat scales, or contour intervals, other than those defined in these tables shall meet an equivalent positional accuracy. The minimum positional accuracy tables are as follows:
1. Scale and contour interval combinations.
Map or Plat Scale
Contour Interval
1" = 20'
1 or 2 feet
1" = 30'
1 or 2 feet
1" = 40'
1 or 2 feet
1" = 50'
1 or 2 feet
1" = 100'
1 or 2 feet
1" = 200'
2, 4 or 5 feet
1" = 400'
4, 5 or 10 feet
2. Vertical accuracy standards.
Contours - Vertical Positional Accuracy
Spot Elevations - Vertical Positional Accuracy
Contour line 1' interval
± 0.60 feet
± 0.30 feet
Contour line 2' interval
± 1.19 feet
± 0.60 feet
Contour line 4' interval
± 2.38 feet
± 1.19 feet
Contour line 5' interval
± 2.98 feet
± 1.49 feet
Contour line 10' interval
± 5.96 feet
± 2.98 feet
Positional Accuracy is given at the 95% confidence level.
3. Horizontal accuracy standards.
Well defined ground points - Horizontal (Radial) Positional Accuracy
Map or Plat Scale
Absolute Horizontal Positional Accuracy
Relative Horizontal Positional Accuracy
1" = 20'
± 0.8 feet
± 0.20 feet
1" = 30'
± 1.1 feet
± 0.30 feet
1" = 40'
± 1.5 feet
± 0.40 feet
1" = 50'
± 1.9 feet
± 0.50 feet
1" = 100'
± 3.8 feet
± 1.00 feet
1" = 200'
± 7.6 feet
± 2.00 feet
1" = 400'
± 15.2 feet
± 4.00 feet
Positional Accuracy is given at the 95% confidence level.
Historical Notes
Derived from Volume 25, Issue 03, eff. December 1, 2008; amended, Virginia Register Volume 32, Issue 06, eff. January 1, 2016.