Chapter 5 Flashcards
- What does “GIS” stand for? What is the definition of GIS?
Geographic Information Systems (GIS):
a computer-based set of hardware and
software used to capture, manipulate,
analyze, and visualize geospatial data
and information.
- Which two main questions does GIS answer? Does GIS answer the “Why” question?
GIS answers “what” and “where”
questions.
- Who was named the father of GIS? What was his major contributions to GIS?
The concept of GIS was first introduced in the early
1960s by Dr. Roger Tomlinson. was the developer of CGIS (Canadian Geographic Information System), which was designed
to provide large-scale mapping of land use in Canada.
CGIS was the first computerized GIS in the world.
- What is the definition of geospatial data? What are the three basic components of geospatial data? Which component is not always required?
Geospatial data is data about objects,
events, or phenomena that have a location
on the surface of earth.
Geospatial data combines:
* Location information: x, y coordinates
* Attribute information: characteristics of the
object or phenomenon
* Temporal information: the time or life span at
which the location and attributes exist
Component not always required:
- What are the three major types of geospatial data?
Vector, Raster, and Attribute Data
What is a vector data model? What are the three types of features that a vector data model uses to
represent the real world?
A vector data model uses points and their associated
geographic coordinates to construct spatial features
representing discrete objects.
Points: zero-dimensional objects, represented by coordinate
locations.
* Lines: one-dimensional objects, created by connecting starting
and ending points
* Polygons: two-dimensional objects that form an area from a set of
lines (or having an area defined by a line forming a boundary)
- What does topology mean in GIS? What are the three basic topological relationships?
Topology refers to the relationship between features. In GIS, topology refers to the spatial association between vector features and objects.
Connectivity – how features are connected to each other
* Adjacency – distance between features
* Enclosure – whether features are nested or apart from each other
- What is a raster data model? Provide some examples of a raster data model.
A raster data model is used to represent continuous features.
National Land Cover Database (NLCD) is a raster dataset that provides nationwide data on land cover and land cover change for the entire United States at 30m spatial resolution.
What are pixels? What does spatial resolution mean? What are digital numbers (or pixel values) in a
raster dataset? What do digital numbers represent?
Data is represented using a set of evenly distributed square grid cells, with each cell representing an area on Earth’s surface.
* These grid cells are also often called pixels or rasters.
The size of a grid cell (pixel) is called spatial
resolution.
Each grid cell has a digital number (DN)
representing the data being modeled
(elevation, temperature, precipitation, land
cover type, etc.)
What is the largest nationwide land cover land use dataset? What type of geospatial data is it?
National Land Cover Database (NLCD) is a raster dataset
Is a vector data model used to represent discrete or continuous features? Is a raster data model used to
represent discrete or continuous features?
Continuous features: Raster
Discrete: Vector
In an attribute table, what does “record” and “field” (or “attribute”) mean? What is a relational database?
What is a “key” used for? Understand that even though attribute data is non-spatial data, it is an
essential component of a geospatial dataset.
- What are the four basic data types of attribute data?
- What is metadata?
- Which organization developed the ArcGIS software? What does “ESRI” stand for?
