ANDSCAPE L INES 9

Surveys

INTRODUCTION

To conduct the historical research and existing conditions investigations

for a Cultural Landscape Report (CLR), several types of surveys may

be needed. Generally, the two primary surveys required are a site

survey and a topographic survey. The site survey graphically documents the findings of a site investigation. The topographic survey

accurately records existing conditions and is often used to prepare a

base plan. Other types of surveys provide site-specific information,

such as legal boundaries and the location of utilities, and are conducted

as needed, based on a CLR’s project agreement. The following

sections briefly describe relevant types of surveys, their purpose in a

CLR, and the expertise required to perform them. SITE SURVEY

Documentation of the existing conditions of a cultural landscape

requires both site research and a site survey. Site surveys are usually

conducted by a historical landscape architect and require the recording

of as much information as is pertinent to, and defined by, the project

agreement.

Site surveys range from general reconnaissance and windshield

surveys to detailed condition assessments for individual features. Site

surveys require on-the-ground fieldwork to inventory and document

existing landscape characteristics and associated features, such as

vegetation, circulation, and land use. Also recorded are contemporary site functions and detailed technical information, as appropriate.

The goal of the site survey is to record the landscape as objectively

as possible.
2 L A N D S C A P E L I N E S

The findings from the existing conditions investigation and site history are compared to identify

the landscape characteristics and associated

features that have significance based on National

Register criteria. Significant landscape characteristics and associated features are those that have

existed since a period of significance and have

retained integrity.

Ideally, a site survey should be preceded by

historical research so that the history and

historic context of the landscape are understood. With this information, the type of

landscape characteristics and associated features likely to be found can be anticipated. In

preparing for a site survey, landscape boundaries should also be determined. If legal property lines are not known, a boundary or cadastral survey may be required before the site

survey. During the site survey it is useful to

have copies of a United States Geological Survey

(USGS) map, a historic site map, an aerial

photograph, historical photographs, and a

topographic survey map.

The appearance of landscape characteristics and

associated features, their physical condition, and

visible changes that have occurred since the

period(s) of significance, should be recorded in a

format that is easily used for analysis and evaluation. A standard form may be prepared for recording observations, including a map for geographically

referencing landscape characteristics and associated

features, and space for writing notes and making

sketches. Field work should include taking black

and white photographs and color slides, as well as

detailed notes and sketches.

A datalogger, a type of hand-held computer

used as a part of a Global Positioning System,

may be used to expedite the recording of site

survey data. A datalogger can be digitally programmed with a “data-dictionary” or standard

inventory form before the survey begins, allowing

responses to be entered in the field. The recorded information can then be downloaded to a

computer. (See Landscape Lines 11: Global

Positioning Systems.)

The scheduling and number of site surveys is

determined by park operational and program

functions, and the management objectives and

level of investigation outlined in the CLR project

agreement. For example, management objectives

may require more than one site survey to investigate the effect of seasonal changes in the existing

conditions of a landscape. Operational or program functions may require site surveys to be

scheduled at only off-season times of the year. A

limited level of investigation may restrict the site

investigation to one site survey. A site survey

must be scheduled during the most revealing

conditions for information gathering; for example,

when wetlands are submerged rather than dry,

when deciduous trees, shrubs, and herbaceous

plants have foliage, when steep topography is

traversable, or when the daily altitude and azimuth of the sun best reveals geologic formations

in black and white photography.

TOPOGRAPHIC SURVEY

A topographic survey (also called a location

ground survey) is an accurate technique for

recording the positions of all detectable landscape
S U R V E Y S 3

characteristics and associated features on or

above grade (ground elevation). Landscape

characteristics and associated features are recorded on a topographic survey map, which is

then used to create a base plan for subsequent

plan drawings, including period plans and existing

conditions plans.

The topographic survey map shows contours at a

prescribed interval and indicates spot elevations of

peaks (high-points), depressions (low-points), and

selected features. (See Figures 1 and 2.) To

determine the position of landscape characteristics and associated features, the survey uses the

horizontal and vertical position relative to an

established “ground control” point. (See “Ground

Control Survey” later in this text.) The types of

features identified include building foundation

outlines, edges of paving materials, fence and wall

lines, surface utilities (poles, wires, transformers,

and manhole covers), water features, vegetation

masses and individual plants, roadway centerlines,

top and bottom of walls, curbs, gutters, and steps.

The level of detail desired in a topographic

survey, such as the contour interval and accuracy

of spot elevations, must be specified. The specifications should indicate that a registered land

surveyor or civil engineer will perform the topographic survey.

Unlike a site survey, a topographic survey does

not record qualitative information about the

appearance, physical condition, or relative

Figure 1. Typical portion of a topographic and utility survey

for Klingle Mansion. Rock Creek Park. (NPS, 1995)

Figure 2. Typical portion of a topographic survey of English

Camp. San Juan Island National Historical Park. (NPS, 1987)
4 L A N D S C A P E L I N E S

importance of a cultural landscape. A site survey

performed before a topographic survey can aid

in selecting features to be recorded in a topographic survey. If a topographic survey is performed before a site survey, the resultant topographic survey map can be used during a site

survey to document landscape characteristics and

associated features.

Aerial photogrammetry is an alternative technique

for obtaining topographic information through the

use of ortho-rectified (horizontally and vertically

georeferenced), aerial photographs. (See Figure

3.) However, because the topographic informaFigure 3. Topographic survey generated using computer aerial photogrammetry. Weir Farm National Historic Site. (NPS, 1992)

tion is derived from a specialized photograph

taken above ground level, the information is less

refined than the information based on a traditional

topographic survey. Aerial photogrammetry may

be used to derive the overall topography of a

large landscape, whereas a traditional topographic

survey may be performed in landscape areas with

a greater density of features. (See Landscape

Lines 5: Graphic Documentation.)

The need and scope of a topographic survey

and its scale depend on the type and size of the

landscape, and the density of existing features.

Also influencing the survey’s scale are the
S U R V E Y S 5

management objectives and the level of investigation for the CLR. Typically the scale of resolution of a USGS topographic quadrangle map at

1: 2400 is too small to accurately depict topographic contours on a 1: 200 base plan. For

larger landscapes, a survey derived from aerial

photogrammetry may be satisfactory and less

expensive than a traditional topographic survey

for obtaining landscape topographic data. If

traditional methods are used to record the

topography of an entire landscape, the costs can

be reduced by using a larger contour interval for

the overall landscape and a smaller (more

detailed) contour interval for areas with a

greater density of features.

Topographic information may be delivered as

either a print document or electronic files (on

disk). If the graphic documentation of a CLR is

produced using computer aided design (CAD), it

is best to receive that information from the

surveyor as electronic files saved as a specified

CAD format. This will make it easier to create a

CAD base plan.

GROUND CONTROL SURVEY

A ground control survey establishes geographic

control points, or benchmarks, to which all

surveyed coordinates relate. The survey records

horizontal and vertical ground control monuments already in place, or positions new ground

control monuments where none exist.

A ground control survey is performed concurrently with other types of surveys to provide

points of reference. If no benchmarks exist or

their coordinates are unknown, establishing a

ground control may be necessary before topographic, utility, or hydrographic surveys are

conducted. Traditional survey equipment, such as

a transit, theodolite, electronic distance meter,

level, and measuring tape is used in this technique. (See Figure 4.) A survey grid is established

from either the ground control monument or

benchmark.

UTILITY SURVEY

A utility survey identifies and locates existing or

abandoned utilities, above and below ground,

and documents their horizontal and vertical

positions relative to a ground control. A utility

Figure 4. Surveyors using laser transits to perform a

topographic survey. San Juan National Historical Park. (NPS,

1987)
6 L A N D S C A P E L I N E S

survey is performed by a certified geophysical

survey contractor and may involve identifying all

utilities or just specified utilities.

Types of information recorded during a utility

survey may include the type of utility, line diameter and location, materials of construction, and

related structures or mechanical features. Geophysical survey equipment, such as ground

penetrating radar, is used to detect the utilities. A

utility survey also requires collection of all existing

documentation from utility companies, although

the documentation does not always include all

site improvements that have occurred over time,

such as the installation of, or modifications to,

drainage, irrigation, and lighting systems.

Utility surveys contribute information to the

development of the site history of a landscape,

but the information is more likely to be useful in

preparing construction drawings for work to be

done as a result of a treatment plan. It may be

more efficient to combine a utility survey with a

topographic survey rather than contracting the

two surveys separately.

CADASTRAL SURVEY

A cadastral survey, which can include and may be

referred to as a property title search, involves

researching the legal description of a property,

including easements, former surveys and permits,

and all other legal records related to the property

through successive ownership. Such documents

are found at the local courthouse, recorder of

deeds office, tax assessors office, and any other

jurisdictional offices.

The product of a cadastral survey may be a

reference file containing copies of all legal

documents related to the property, or a composite map that graphically presents legal

information about the property. The survey

may include a narrative or graphic description

of the property in metes and bounds, a copy of

the property plat, deeds, previous plats, permits or easements (such as utility easements),

and ground control monuments. This information can be used to understand the historic and

contemporary legal status of the property, to

date certain features of the landscape shown or

described in legal documents, and to identify

any legal restrictions associated with the preservation and management of the landscape.

(See Figure 5.) A historian, historical landscape

architect, or other technical staff members can

perform the survey.

BOUNDARY SURVEY

A boundary survey establishes legal property lines

by locating and identifying coordinates for the

boundaries of a cultural landscape. Knowledge of

property boundaries is important for performing

other kinds of surveys, such as topographic and

utility surveys. Ideally, the location of property

boundaries should be known before a site survey

is performed.

A registered land surveyor or civil engineer will conduct a boundary survey when no record of property

lines exists, or when no legal boundary markers are

found on the property. Boundary surveys are performed using traditional survey equipment and they

are often conducted with topographic and cadastral
S U R V E Y S 7

Figure 5. A historic cadastral survey map, performed by the Works Progress Administration in Atlanta. Map indicates the dwellings,

property frontage, street width and alignment, and sidewalk conditions along Auburn Avenue. Martin Luther King, Jr., National Historic

Site. (NPS, 1937)
8 L A N D S C A P E L I N E S

surveys. The boundary survey may locate boundary

markers and produce a narrative or graphic description of the property boundaries.

HYDROGRAPHIC SURVEY

A hydrographic survey maps the submerged

topography and configuration of natural or

constructed water features and locates and

identifies underwater objects. A certified geophysicist contractor often performs this survey

with an archeologist.

Geophysical survey equipment mounted on a

floating vessel is used to conduct the soundings of a

hydrographic survey. A side scan sonar uses

reflected acoustic energy to record topography

and locate submerged objects. Soundings are taken

at regular intervals along survey lines perpendicular

to the shore line. Supplementary soundings are

taken of objects or features of particular interest,

which may include sewer outfalls, sedimentation

areas, spillways, dams, and rock outcroppings. The

horizontal and vertical location of soundings is

based on established ground control points.

Topographic and location information is received

by a recorder and can be printed as a survey map

or stored as an electronic file.

A hydrographic survey may be limited to investigating to a specified depth of sediment or surface

geology beneath certain water features. Sediment

cores or rock samples are taken from the bottom

of the water feature using boring equipment.

Archeologists, geologists, geophysicists, and

archeobotanists may analyze the samples to

better understand the cultural and natural history

of the water feature and its environment.

A hydrographic survey may be necessary as part

of an existing conditions investigation to better

understand the underwater qualities of a water

feature. This may be particularly important when

a water feature contributes to the significance of a

landscape, when the presence of submerged

cultural artifacts is suspected, and when the size,

shape, or depth of a water feature has changed

since a historic period and the cause or effect of

this change needs to be understood.

The mission of the Department of the Interior is to protect

and provide access to our Nation’s natural and cultural

heritage and honor our trust responsibilities to tribes.

U.S. Department of the Interior

National Park Service

Cultural Resources

Park Historic Structures & Cultural Landscapes