Field data consists of observations collected at or near the ground in support of remote sensing analysis.

Field data must include the following:

• Attributes or measurements that describe ground conditions

• The location and area (size) • The time and date

Data may be based on an established classification system such as these land-holding units in Brazil. The

numbers represent areas visited by field teams.

A field sketch showing the documentation of data

Filed notes documenting such items as acreage, land use, irrigation, fertilization and more

A field radiometer permits and analyst to compare ground data with data gathered from an aerial sensor.

Radiometers may be situated in truck-mounted booms to retrieve overhead views.

Use of ground radiometers requires knowledge of sun-earth relationships in regard to reflection and scatter of

energy.

Unmanned airborne vehicles are remotely piloted aircraft that can carry cameras or other sensors.

Aerial videography is the use of video images to record aerial imagery using commercial video cameras This

can be done quickly and inexpensively with relative fine resolution.

Global Positioning System (GPS) has enhanced the usefulness of remote sensing data when it is necessary

to integrate image data with field data.

GPS receivers permit analysts to download information in the laboratory for use with geographic information

system (GIS) or image processing systems.

Panoramic ground photograph using software to fuse together sequence of photographs to provide a 360°

view.

Sampling is done when inventories of large areas are not feasible. Simple random sampling pattern is below. The coordinates for the circled dot are row 2, column 7.

Stratified random sampling uses subdivisions which receive specific allocations of sampling points.

Systematic sampling positions observations at equal intervals. This method sometimes causes sample

points to fall on geographically similar areas.

Stratified systematic non-aligned sampling pattern combines both features of systematic and stratified

samples.

Cluster sampling selects points within a study area, and then additional satellite observations are placed

nearby.