GIS Ch. 8

doughnut buffer

a buffer around a polygon feature that does not include the area inside the buffered polygon

setback buffers

a buffer around a polygon feature that only extends inside of the polygon boudnary

quantile

a choropleth mapping technique that classifies data into a predefined number of categories with an equal number of units in each category

natural breaks (or jenks)

a choropleth mapping technique that places class breaks in gaps between clusters of values

equal interval

a choropleth mapping technique that sets the value ranges in each category to an equal size

map legend

a common component of a map that facilitates interpretation and understanding

split

a geoprocessing operation that divides an input layer into two or more layers based on a split layer

clip

a geoprocessing operation that extracts those features from an input point, line, or polygon layer that falls within the spatial extent of a clip layer

erase

a geoprocessing operation that preserves only those areas outside the extent of an erase layer

cluster tolerance

a geoprocessing setting that forces nearby vertices to be snapped together if they fall within a user-specified distance

append

a geoprocessing technique that combines adjacent polygon datasets into a single dataset

dissolve

a geoprocessing technique that removes the boundary between adjacent polygons with identical values

choropleth maps

a mapping technique that uses graded differences in shading, color, or symbolology to define average values of some property or quantity

sliver

a narrow gap formed when the shared boundary of two polygons do not meet exactly

in the context of geoprocessing operations, which of the following is true of the clip?

all attributes from the preserved portion of the input layer are included in the output

instersection

an overlay method that contains common features and attributes from both the input and overlay layers

symmetrical difference

an overlay method that contains those areas common to only one of the feature datasets

identity

an overlay method that creates an output layer with the spatial extent of the input layer but includes attribute information from an overlay

union

an overlay method that preserves all features, attribute information, and spatial extents from an input layer

polygon-in-polygon overlay

an overlay technique in which a polygon input and overlay layers are combined to create an output polygon layer with the extent of the overlay

line-in-polygon overlay

an overlay technique in which each line that has any part of its extent withing the overlay polygon layer will be included in an output line layer

line-on-line overlay

an overlay technique in which output from this operation is a point(s) located at the intersections of the two linear datasets

Polyogn-on-line overlay

an overlay technique in which polygon features that overlay lines are selected and subsequently preserved in an output layer

polygon-on-point overlay

an overlay technique that creates a polygon layer from those input polygons that overlay features in a point layer

point-in-polygon overlay

an overlay technique that creates an output point layer that includes all the points occurring within the spatial extent of the overlay layer

geoprocessing

any question used to manipulate spatial data

in the context of single layer analysis in vector operations, a variable width buffer differs from a constant width buffer in that the variable width buffer:

calls on a premade buffer field within the attribute table to determine the buffer for each specific feature in the dataset

___ is a geoprocessing setting that forces nearby vertices to be snapped together if they fall within a user-specified distance

cluster tolerance

in the context of single layer analysis in vector operations, the ___ operation combines adjacent polygon features in a single feature dataset based on a single predetermined attribute

dissolve

the ___ is the geoprocessing operation which preserves only those areas outside the extent of the analogous erase layer

erase

the ___ is the overlay method that creates an output layer with the spatial extent of the input layer but includes attribute information from the overlay

indentity

the output layer produced by the ___ method covers the spatial extent of the overlay and contains features and attributes from both the input and overlay

intersection

in the context of single layer analysis in vector operations, which of the following is accomplished by the dissolve tool?

it combines all adjacent features with the same attribute values

in the context of single layer analysis in vector operations, which of the following is accomplished by the append tool?

it combines the spatial extend of two or more layers

which of the following is true of a sliver?

it occurs when two slightly misaligned vector layers are overlain

if a town's municipal authority wanted to find all railway crossings and convert them into manned railway crossings, which of the following overlay operations should they employ to find all road-rail intersections?

line-on-line

the output from a ___ overlay operation is a point or points located precisely at the intersection of the two linear datasets

line-on-line

in the context of single layer analysis in vector operations, the ___ operation combines features within a point, line, or polygon layer into a single feature with identical attribute information

merge

multiple ring buffers

multiple concentric regions of a specified width around points, lines, or polygons

in the context of single layer analysis in vector operations ___ buffers are made such that a series of concentric buffer zones are created around the originating feature at user-specified distances

multiple ring

how do setback buffers differ from doughnut buffers?

only areas inside the polygon boundary are buffered

what is the process of taking two or more different thematic maps of the same area and placing them on top of one another to form an new map known as?

overlay

continuous features

phenomena that lack clearly defined boundaries

discrete features

phenomena that when represented on a map have clearly defined boundaries

buffering

placing a region of specified width around a point, line, or polygon

upon performing a ___ operation, a new output point layer is returned that includes all the points that occur withing the spatial extent of the overlay

point-in-polygon overlay

during overlay operations, one of the overlay dataset must always be a:

polygon or a line layer

a spatial join relationship is explicitly based on the property of ___

proximity

constant width buffers

regions of constant width around points, lines, or polygons

variable width buffers

regions of variable width around points, lines, or polygons

in the context of single layer analysis in vector operations, a constant width buffer differs from a variable width buffer in that the variable width buffer

requires users to input a value by which features are buffered

map generalization

the process by which real-world features are simplified in order to be represented on a map

map abstraction

the process by which real-world phenomena are transformed into features on a map

overlay

the process of taking two or more different thematic maps of the same area and placing them on top of one another to form a new map

symbolization

the use of various text, icons, and symbols to represent real-world features

merge

to combine adjacent or overlapping spatial features into a single feature

select

to define a subset of the larger set of data points or locales

error propagation

when inaccuracies are present in the original input and overlay layers and are carried through to an output layer