GIS Midterm Exam Vocabulary & Definitions

data acquisistion

collecting data from various sources

data storage and retrieval

getting data into appropriate computer hardware in digital format and in a way that makes it easily accessible and usable

database management

organizing, storing, and manipulating large amounts of information

data processing

creation of structured data

data display and interaction

displaying spatial data and working with it on a monitor

spatial data analysis

various ways of performing queries about geographic data, and creating models to simulate the behavior of geographic processes

data synthesis and presentation

end result of a GIS project

spatial information

features like roads, lakes, buildings, etc.

nonspatial information

specific information like names, classification, etc.

topology

location of objects in space relative to each other

vector model

Objects represented by the points and lines that define their boundaries

raster model

divides a map into grid cells, each cell is assigned a value that represents a real world attribute

continuous data

information that occurs everywhere on earth, ex. air quality, temperature, elevation

discrete data

information that only occurs in selected places, ex. land use, income

scale

relationship between the size of a feature shown on the map and the size of the feature in the real world

aggregated data

data from more than one source and grouped for comparison

projections

formulas to transform coordinates to plane geometry

graduated color maps

a map that divides numeric data from a polygon feature class into classes based on value and displays the classes with different colors

proportional symbol map

a thematic map in which the size of a symbol varies in proportion to the frequency or intensity of the mapped variable.

Isarthmic Map

maps a continuous variable

flow maps

show movement from one place to another.

key relationships of spatial data

contiguity, connectivity, containment

what is a geographic question

A question that can be answered byunderstanding the spatial relationshipsbetween the spatial objects including theinformation attached to it (populationcharacteristics, details about events,boundaries, etc.)

query

a question often expressed in a formal way

geoprocessing

variety of operations on spatial data that generates new information from a combination of data layers

overlay

combines multiple data layers to make visual comparisons of generating information

vector

points, lines, and polygons

raster

cells

longitude

Distance east or west of the prime meridian, measured in degrees

latitude

Distance north or south of the equator

contiguity is

a feature sharing at least one part of it's boundary

data in GIS is represented using

vector and raster

in GIS, each object has a coordinate that lets us know

the location of the object respective to the real world

qualitative map

maps nominal value, categories

quantitative map

maps numerical value, classification

dot density maps

use dots to express the volume and density of a particular geographic feature

cartograms

A type of thematic map that transforms space such that the political unit with the greatest value for some type of data is represented by the largest relative area.

ordinal scale

Quantities that can be placed in order.the order matters but not thedifference between values.

interval

Measure the equal distance between them

ratio scale

Place values in order based on a pre-defined interval or differences

natural breaks

a data classification method that selects class break levels by searching for spaces in the data values

quantile

a classification method that attempts to place an equal number of data values in each class

equal breaks

equal numbers in each group

Select two of the following objects that you can store in a file geodatabase

Feature classes & nonspatial attribute tables

Geodatabase Schema refers to the structure of the geodatabase, feature classes, tables, and any other components you may have.

true

buffer

typically an area with a specified distance radiusfrom a feature or an outer boundary of a feature

geoprocessing

A variety of operations on spatialdata that generates newinformation from a combinationof data layers

overlay

Combines multiple data layers to make visual comparisons for generating information

dissolve overlay

combines data that have been categorized and reclassify that data based on a newset of rules

merge overlay

combine data that are adjacent or contiguous into one layer with the intent of keeping the same attributes (information) from both features. Fields that are not the same will not appear in the new feature

clip overlay

removes an area within a boundary of another feature

union overlay

combines layers and all the attributes of those features together.

intersect overlay

overlays two layers that have the combined data of both. Only those that fall within the overlapping boundary of these features.

spatial coincidence analysis

overlays locations of hazard sources within an analytical unit as a proxy exposure to environmental toxins

The following are some of the essential functions of ArcGIS, EXCEPT

Develop policy recommendations

what is a layer?

A spatial object with attributes

When you are working with Polk County boundary as your geographic extent, what is the most appropriateway to show public school facilities in the map?

points

the joins and relates operation allows you to

Join a layer to another layer or table based on a common field with the same data type (e.g., text, double, long)

Which classification methods give you an initial understanding of how your data is grouped by the cluster ofbreaks

natural breaks