Exam 1 Material

geograpic

types of coordinate systems: coordinates (f, l, z) (used gravity to define elevation

projected

types of coordinate systems: coordinates (x, y, z) on a local area of the earth's surface

cartesian

types of coordinate systems: coordinates (x,y,z) for the whole earth

cluster tolerance

specifies distance at which all vertices or boundaries are considered coincident vertices falling within this tolerance are snapped together

geodesy

the shape of the earth and definition of earth datums

skeletonizing

the thinning of lines in a raster image

map projection

the transformation of a curved earth to a flat map

average of cell, center of cell, at grid nodes

Data for a raster can be taken 3 ways:

ellipsoid

Datum type: Smooth - Easily calculated

geoid

Datum type: places earth surface at "mean sea level" - Surface of constant gravity

explicitly, topological, continuous, spatial, filtering

Disadvantages of Vectors: • The location of each vertex needs to be stored _________ • For effective analysis, vector data must be converted into a _______________ structure • _______________ data, such as elevation data, is not effectively represented in vector form • __________ analysis and _____________ within polygons is impossible

feet

NAD27 units?

feet or meters

NAD83 units?

DMS or DD

Geographic coordinate system units include?

easy, nearly impossible

Vector is raster conversion is _____________. Raster to vector is _______________.

mixed pixel problem

What is it called when a square on a raster could be categorized as more the one attribute? ex: water or land

10-19

What is the range of UTM zones for the contiguous US states?

vertex

What is topology? Where points, lines, and polygons share individual ____________. Move a point and it moves a vertex in a line/polygon, and vice versa.

geometries, adjacency, overlap,

What is topology? Shared __________, __________, and ________________

adjacent

What is topology? Two polygons that share vertices are considered _______________.

overlapping, errors

What is topology? ___________________ (or non-overlapping) features can be located, and then marked as ___________.

Universal Traverse Mercator

What projection? Cylindrical projection - axis through equator and 60 such projections around the equator

Mercator

What projection? Cylindrical projection - axis through poles and Uses Global Coordinate System - Lat/Long

nominal

attribute data type: one able to distinguish one thing from another ex: eye color, sex, wood vs. forest

line smoothing

can be used to make irregular lines into more organic, free flowing features with curves

ordinal

attribute data type: able to order data ex: hardness of minerals, good/better/best

ratio

attribute data type: both ratios and differences are meaningful (zero means "nothing") ex: temp in K, money, age

interval

attribute data type: difference between measurements is meaningful (ie: unit of measurement exists) ex: temp in C or F, calendar dates

raster and vector

What are the two major families of GIS data?

feature, choropleth, dot density, contour (isopleth)

What are the types of maps?

George Boxy

"Essentially, all models are wrong, but some are useful"

geographic coordinate system, latitude, longitude, ellipsoid, elevation, geoid, datums

(f, l, z) or (phi, lamda, zeta)Global reference system for determining exact position of a point on Earth ___________ (f) and ____________ (l) defined using an _________, an ellipse rotated about an axis. Elevation (z) defined using ___________, a surface of constant gravitational potential. Earth ___________ define standard values of the ellipsoid and geoid.

coordinate systems

(x,y) coordinate systems for map data

attribute data

- are used to record the nonspatial characteristics of an entity - can be envisioned as a list of characteristics that help describe and define the features we want to represent in GIS; & - are often arranged in rows and columns

prime meridian, equator

0 is the location of the _______________ (latitude) and ____________ (longitude).

discrete and continuous raster

What are the types of raster data?

array, surfaces, localized, scanned, remotely sensed

A grid or raster maps directly onto a programming computer memory structure called an _______. Grids are poor at representing points, lines and areas, but good at _________. Grids are good only at very ___________ topology, and weak otherwise. Grids are a natural choice for ___________ or remotely sensed data. Grids suffer from the mixed pixel problem.

datum

A model or reference surface. (Mimics the shape of the earth.)

generalization, aesthetically, conversion, location, areas, lengths, connections

Advantages of Vectors: • Data can be represented at its original resolution and form without _______________ • Graphic output is usually more ______________ pleasing (traditional cartographic representation) • Since most data, e.g. hard copy maps, is in vector form no data ______________ is required • Accurate geographic ______________ of data is maintained • Ideally suited for certain types of analysis, especially ________, __________, __________________.

focal length, 0

An ellipse is a curved line forming a closed loop. Defined by a _______ _________ = E Distance (F1, P, F2) is constant for all points on ellipse When E =___, ellipse = circle

2-D, 3-D

Coordinate data: Cartesian, can be one of 2 ways

origin, latitude, longitude

Coordinate data: Spherical

360, 60, 60

DMS: __________ degrees, each degree is _____ minutes, each minute is __________ seconds

quantitative, properties, attributes

GIS and spatial analyses are concerned with the ______________ location of important features, as well as the ______________ and ______________ of those features.

map design

Good _______ _________ uses similar text/font, word and legend placement is good and not hiding important information, colors work well.

equator, south pole

In the northern hemisphere, the origin is the equator and all distances north (or 'northings') are measured from the _________. In the southern hemisphere , the origin is the ___________ and all northings are measured from there. (elimnates negative values)

GIS Components

Large high resolution display, high speed computer, high quality hard copy graphic and text outputs, coordinate and text input devices, network and web data communication, rapid access to mass storage, archival storage

countour

Map type: elevation, height

isopleth

Map type: multiple lines to show variation such as elevation

choropleth

Map type: on color (value) per area or boudary

feature

Map type: roads and cities

dot density

Map type: show population, etc.

spatial

Maps represent... physical entity represented by __________ object

internal rings, multiple parts

Polygons may include __________________ that act as "donut holes" - areas excluded from the surrounding polygon. Polygons (and points and lines) may also include _______________.

Lambert Conformal Conical

Projection: Cone intersects Earth at two parallels, Distortion smallest near standard parallels, East-West zones

Transverse Mercator

Projection: Cylindrical projection with the tangency being the intersection between cylinder and earth, Distortion smallest at Central/Standard Meridians, Creates north-south zones

Mercator

Projection: __________, developed in 1569 for use as a navigation aid (retains the shape)

implied, origin point, program, perform, mathematical, quantitative, discrete, grid

Raster Advantages: -The geographic location of each cell is __________ by its position in the cell matrix. Accordingly, other than an origin point, e.g. bottom left corner, no geographic coordinates are stored. • Due to the nature of the data storage technique data analysis is usually easy to _________ and quick to ____________. • The inherent nature of raster maps, e.g. one attribute maps, is ideally suited for __________ modeling and ___________ analysis. • _________________, e.g. forestry stands, is accommodated equally well as continuous data, e.g. elevation data, and facilitates the integrating of the two data types. • _____-cell systems are very compatible with raster-based output devices, e.g. electrostatic plotters, graphic terminals.

resolution

Raster Data: Storage space increases by the square of the _____________. Portraying large areas at high precision is problematic.

size, linear, large, one, vector, generalization, size, output

Raster Disadvantages: - The cell _________ determines the resolution at which the data is represented • It is especially difficult to adequately represent ________ features depending on the cell resolution. Accordingly, network linkages are difficult to establish • Processing of associated attribute data may be cumbersome if ________ amounts of data exists. Raster maps inherently reflect only one attribute or characteristic for an area • Since most input data is in __________ form, data must undergo vector-to-raster conversion. Besides increased processing requirements this may introduce data integrity concerns due to _______________ and choice of inappropriate cell _______. • Most _________ maps from grid-cell systems do not conform to high-quality cartographic needs

density, distance, interpolation, least cost path, viewshed, buffers

Raster analysis functions include

1, numeric

Raster contains ___ value may be stored indicating a single attribute— road type for example. Need a new raster if you want another attribute, and only _________ attributes can be stored.

spheroid

The earth is actually a _____________ not a perfect sphere. (larger at equator than poles)

thematic layers

Spatial data are often stored as separate ____________ _____________.

positive longitude, negative longitude

Spherical coordinates: E is __________ ____________ while W is _________ _____________.

positive latitude, negative latitude

Spherical coordinates: N is _______ ______________ while S is _______ ____________.

oblique, lamber conformal conic, transverse mercator

State Planar Systems: Panhandle of Alaska: ___________Mercator (at angle) • N/S states (California): _________________________ • E/W states (New York): _________________________

southern, 500,000, 2,000,000

State Plane Zones: Using NAD27 • Northing is measured from the ___________border • Easting is measured differently: • For TM projections, the measurement is from ____________ feet west of the principal meridian • For Lambert Conformal Conic, the measurement is from _______________ feet west of the principal meridian

topology

Study of geometric properties that do not change when the forms are bent, stretched or undergo similar transformations (textbook definition)

SW

The _______ corner of a state will be it's origin, or it will have a false origin.

arcs

The answer to way-finding lies in structuring data to include information about the relationships between the roads (or ________) in the database.

time zones

The lat/long system of GCS serves a basis for breaking earth up into multiple _________ to account for difference in time around the world • Greenwhich Mean Time or GMT

D= integer , M = decimal x 60, S = second decimal x 60

To convert DD to DMS...

D + M/60 + S/3600

To convert DMS to DD...

four

To solve for the unknowns we need to select a least _______ coordinates that can be physically identified in both of the coordinate systems. (road and peninsula tips often used)

translation, scaling, rotation

To transform coordinates systems in digitizing from one to another we use...

scaling

Transformation: X and Y are multiplied resulting in larger image

rotation

Transformation: X sin(theta) and y cos(theta), turns/pivots image

translation

Transformation: moving from x,y (+) without changing shape or size

north, south

UTM minimizes distortion from ________ to _______.

central meridian, meters, 60, east, west, northing, easting

UTM: - Line of intersection at a _____________ __________. • Distances measured with respect to the central meridian and from the equator in _______ • ____ zones around the Earth from ______ to _______ • False _____________ and False ____________

false northing

UTM: In the southern hemisphere, 10,000,000 is the value assigned to the equator. So something 120,000 meters south of the equator is depicted as 9,880,000

false easting

UTM: to avoid negative values: Central meridian is denoted as 500,000 not "0"

8, 6

Unknown coefficients in transformation: With four points we can write ____ equations one for each x and y coordinate. These equations are solved simultaneously to yield the ___ coefficients.

cylindrical, conical, and azimuthal

What are the 3 major types of distortion?

real life, data model, data structure, machine code

What are the levels of abstraction?

NAD83

Which ellipsoid? - North American Datum, 1983 - an update to NAD27

NAD27, Meades Ranch, triangulation

Which ellipsoid? NAD27 - North American Datum, 1927 - Surveying started at _____________ in Kansas - Series of point measurements by _______________ survey to identify "benchmark" locations

WGS84

Which ellipsoid? World Geodetic System, Dept. of Defence datum for GPS (Concern that ships knew where they were within 100 ft., but maps were off by half a mile)

1:24,000

Which is a larger scale map? 1:24000, 1:100,00, 1:250,000

north, central, south

Wisconsin has a _____________ , ______________, and _____________ zone for the state planar system.

conical

Wisconsin uses __________ projection to minimize distortion from east to west.

bitmap, pixelation

_________ is a type of raster file, is the reason while enlarging the photo will become blurry due to ________________.

large, small

__________ scale maps show fine detail and __________ scale maps show large broad regions.

coordinates, attributes

___________ and _____________ are used to represent entities

points

___________ in the real world can be converted to vector encoding (x,y coordinates) to make an image

longitude, 0, 180, 180, 92

____________ Runs in North to South from North Pole to South Pole direction • ___ degrees is the Prime meridian • Then west to _____ degrees west - the international date line East to ______ degrees east - the international date line • Platteville is about the ___nd meridian

raster

____________ is the best way to store continuously changing values such as elevation, Analysis faster and more flexible than vectors for many applications, Some analysis only possible using rasters

higher, lower

____________ resolution means more pixels while ____________ means less.

vector

______________ is coordinate based (cartesian, polar, 3D, linear), topological, object oriented

raster

______________ is grid based

polygons

______________ must close upon themselves, so that the first and last vertex are the same.

latitude, 0, 90, 90, 42

_______________ Runs in an east-to- west direction • ___ degrees = equator serves as starting point • ___ degrees north = North Pole • ___ degrees south = South Pole • Platteville is about _____ degrees north latitude

GIS

a computer-based system to aid in the collection, maintenance, storage, analysis, output, and distribution of spatial data and information

Functions of GIS software

data entry, analysis, editing, data management, ouput

spatial data model

defined as the objects in a spatial database plus the relationships among them

prime meridian, equator

geographic coordinate system: The reference points are _______ ___________ at Greenwich and ____________

map generalizations

help show imporatant information: truth, fused, simplified, displaced, omitted, exaggerated

digitizing

is the process by which coordinates from a map, image, or other sources of data are converted into a digital format in a GIS

vertices, nodes

lines consists of ____________ (points connecting lines) and _____________ (points where lines overlap).

digitizing errors

overshoot, pseudo-nodes, undershoot, line crossing with no node, polygon point label inbetween lines, etc.

snapping

places points or features within specified distance and snaps them together.

geometrically, gravitationally

the Z coordinate in Cartesian and projected coordinated systems is _________________defined; in geographic systems the z-coordinate is defined _________________.

smaller

the __________ the root mean square error is the better. (more precise transformation)

5, 8

time zones: East cost of US is ___ TZ to the west of PM, West coast lies- ___TZ to the west of PM

15

time zones: the sun "moves" ____ degrees per hour

Mechanism for navigating between features using their topological relationships - way finding

topology GIS multiple meanings: How to get from origin to destination?

Mechanism allowing features to share geometry, polygon, edge-node, geodatabase

topology GIS multiple meanings: Area features can share boundaries (________ topology). Line features can share endpoints (________ topology).In addition, shared geometry can be managed between feature classes using a _____________ topology. For example: Line features can share segments with other line features.

Theory or model of features in space

topology GIS multiple meanings: A specific type of vector data model that was utilized by ESRI to represent linear features and polygons is the arc-node model. The model manifests itself in GIS data as a specialized data structure that supports analysis functions.

validation

topology GIS multiple meanings: Set of ___________ rules

Set of editing tools for integrated features

topology GIS multiple meanings: example would be cluster tolerance setting

coordinates, attributes

vector data models: ____________ are used to define boundaries and ______________ are used to define features properties.

multiple representations

vector data models: features can be represented in multiple ways in different layers. (ex: a building could be a point, line, or an area)

web soil survey

what is one attribute database example given in class?