Geospatial Data Concepts and Data Capture Methods

Vocabulary flashcards covering geospatial data concepts, data formats, surveying methods, census and sampling types, digitization, and scanning parameters.

Geospatial Data

Location-based data tied to a location on Earth that describes natural and human-made features and enables spatial analysis.

Discrete Geospatial Data

Categorical or discontinuous data with values that change abruptly from one category to another.

Continuous Geospatial Data

Data with values that vary continuously across a surface with no abrupt or sharp boundaries.

Vector Data

A format for discrete features represented using points (e.g., wells, trees), lines (e.g., rivers, roads), or polygons (e.g., land parcels, lakes).

Raster Data

A format for continuous surfaces composed of grids or pixels where each cell stores a specific value, such as temperature or elevation.

Attribute Data

Descriptive information linked to geographic features, such as the population of a city or a land use category.

3D Geospatial Data

Geospatial data incorporating elevation information, such as LiDAR point clouds.

4D Geospatial Data

Geospatial data created by adding a temporal (time) dimension to 3D datasets.

In Situ Data Collection

The process of collecting real-world data directly at the location being studied using specialized instruments on site.

Land Surveying

The process of recording geographic positions and attributes from the real world, based largely on triangulation.

Triangulation

The surveying process of determining geographic positions by measuring angles.

Census

The systematic collection of information about all members of a specific population.

Population (Statistical)

Every member of a specific group, such as the entire population in the US Decennial Population Census.

Sampling

A technique utilized when limited by resources to collect a fair representation of a population.

Random Sampling

A sampling method in which every member of the population has an equal chance of being selected.

Systematic Sampling

A sampling method where population members are listed in order and chosen at regular intervals.

Stratified Sampling

A sampling method where the population is divided into meaningful subgroups, and a sample is selected from each subgroup using a random or systematic method.

Digitization

The process of converting coordinates from a map, image, or other source into a digital format via digitizing or scanning.

Manual Digitizing

Tracing feature outlines using a puck and an electronically-sensitive tablet to generate a string of points with x, y values.

Heads Down Digitizing

A digitizing approach that involves looking down on a physical digitizing tablet while tracing feature outlines.

Heads Up Digitizing

A digitizing approach where the operator looks up at a computer screen and traces features using a mouse or pen.

Coordinate Transformation

The process of converting tablet coordinates measured from an origin into real-world geographic coordinates.

Control Points

Points or locations of interest with known coordinates on a paper or digital map used to spatially reference coinciding datasets.

Scanning

A method that places a map or photograph on a glass plate, passes a light beam over it, and measures reflected light intensity to produce a pixel grid.

Spatial Resolution (Scanning)

A scan parameter defined as dots per inch (DPI) or pixels per inch on a monitor.

8-bit Color

A color resolution ($2^8$) providing 256 shades of black and white or preselected hues.

24-bit Color

A color resolution ($2^{24}$) providing 16.8 million unique colors using RGB with 8 bits per hue.

Single Pass (Scanning)

A color capture method in scanning where all colors are recorded in one pass.

Multiple Passes (Scanning)

A color capture method in scanning where each RGB color channel (Red, Green, Blue) is captured separately.