First Test Textbook Flashcards
Discrete Data
are objects in the real world with specific locations or boundaries, such as houses, cities, roads, or counties
continuous data
represent quantities that may be measured anywhere on the earth, such as temperature or elevation
vector model
which is designed to store discrete data
raster model
which is designed to store continuous data
both models are georeferenced
vector and raster
geospatial
data and software used to work with georeferenced information are encompassed by the vernal term.
basic shapes to represent discrete objects that vector model
features; include point, polygon,line
feature class
similar features stored together; can store only one type of feature: points, or lines or polygons but never a combination
map scales
a measure of the size at which features in a map are represented
source scale
a scale that geographic data set has; the original scale or resolution at which it was created or converted to digital form.
scale range
specifies the range of scales for which the display of the data is valid so that it will only be shown at those scales
geometric accuracy
describes how closely the x-y values of a data set correspond to the actual locations on the earth surface
thematic accuracy
refers to the attributes stored in the table
resolution
refers to the sampling interval at which data are acquired; may be spatial, thematic or temporal; indicates at what distance interval measurements are taken or recorded
precision
refers to either the number of significant digits used to record a measurement or the statistical variation of a repeated single measurement
convention
refers to the use of a particular color or symbol in a commonly understood way
nominal data
name or identify objects, such as the names of states
categorical data
separate features into distinct groups or classes
ordinal data
have categories that are ranked based on some quantitative measure, although the measure may not be linear
ratio data
have a meaningful zero point that indicates the absence of the thing being measured
interval data
have a regular scale but are not related to a meaningful zero point
graduated symbol map
point or line data are usually displayed by varying symbol size or thickness and are portrayed using this
proportional symbol map
point or line data is portrayed; which the numeric value is used to proportionally determine the size of the symbol
graduated color maps or choropleth maps
numeric data classes for polygons are represented using color shaded symbols
bivariate choropleth map
can be used to compare the spatial patterns of two numeric variables
dot density map
uses randomly placed dots inside each polygon to show magnitude of a value in the attribute table
chart map
is a type of graduated symbol map that replaces the symbol, such as circle or triangle with a small bar or pie chart capable of showing several variables at once
thematic raster
represents features or quantities such as roads, geology, elevation or vegetation density
