About Me

Eastern/Chadrow Associates, Inc. (ECA) is located Warminster, Pennsylvania, and specializes in land surveying, civil engineering, and planning for residential, commercial, industrial and municipal projects. If you are a homeowner, developer, architect, engineer or site contractor, ECA has the experience, tools and ability to make sure the job is completed from beginning to end. In addition to our many services and state-of-the-art equipment, we provide prompt service and attention to detail.

Monday, May 2, 2011

What is a Topographic Map?

Topographical Maps (elevation maps) are created from a topographical survey of land in which the existing features of the property are located in addition to the ground height elevations referenced to a know datum, usually the height above sea level. The United States Geodetic Survey (USGS) &/or United States Coastal & Geodetic Survey (USC & GS) are based on this datum. Since a topographic map is only a two dimensional surface, ground elevations can only be expressed as individual spot labeled elevations &/or contour lines which are labeled at a known interval. The contour lines on a topographic map can be subtracted from each other giving a calculated rise or fall in the land. Contour lines that are very close together signify very steep conditions while contour lines that are very far apart signify very flat conditions.

Topographic Maps are generally created by land surveyors, civil and environmental engineers and are used to prepare development plans, stormwater design, erosion control, septic design where grading & drainage design is critical to the construction of a proposed development. Visit Eastern Chadrow’s Web site to have them produce a Topographic Map for you.