GeoSci 170

How many times zones are there?

24, 15 degrees of longitude wide

How many zones does UTM divide the earth into (north/south)?

60

Global Positioning System (GPS):

Acquiring real-time location information from a series of satellites in Earth's orbit.

Remote sensing (RS):

Acquisition of data and imagery from the use of satellites (satellite imagery) or aircraft (aerial photographs).

qualitative change map

Change in the category of features over time at the same location. Change in the location of a feature over time.

Geographic Information System (GIS):

Computer-based mapping, analysis, and retrieval of location-based data.

latitude

The measurement, in degrees, of a place's distance north or south of the equator. 0-90 degrees

Isoline

a line that connects points of equal value on a map. Isolines are commonly used to show quantities that vary smoothly over a surface.

Qualitative Map

a map showing the location/distribution of a phenomenon using nominal data

Quantitative Map

a map showing the magnitude/value of a phenomenon using ordinal, interval or ratio data

Qualitative Change Map

a map showing the qualitative change of geographic phenomena/features over time, such as a change in feature category or the change in the location of features.

Single-theme Map

a map that only depicts one theme or attribute at a time

Multivariate Map

a map that simultaneously displays two or more themes or feature attributes to describe geographic relationships between the phenomena

Origin of SPC zone:

a point established to the west and south of the SPC zone with easting and northing values of 0.

State plane coordinate (SPC) system

a set of 124 geographic zones or coordinate systems designed for specific regions of the U.S. Each state contains one or more state plane zones, the boundaries of which usually follow county lines.

Projection surface

a simple geometric shape capable of being flattened without stretching, such as a cylinder, cone, or plane

Fishnet

a type of 3D surface constructed by closely spaced line profiles in two directions. From a perspective view, the height of each grid varies to create an impression of 3D.

Isopleth

a type of isoline, in which the values are ratios that exist over areas, such as population per square kilometer or crop yield per acre

Thematic Map

a type of map showing one or a few themes of information for a specific area, which is often coded, colored, or grouped for convenience. These maps can portray physical, social, political, cultural, economic, sociological, agricultural, or any other aspects of a specific area, such as a city, state, region, nation, or continent.

Reference Map

a type of map showing the simplest properties of the geographic features in a specific area, such as political boundaries, roads, water bodies and cities.

Quantitative Thematic Map

a type of map that describes any magnitude/numerical information about spatial features and their relationships. Such maps answer questions like how much, many, large, wide, fast, high, or deep things are, using interval or ratio data.

Cartogram

a type of map that distorts area (size and geographic borders) in proportion to the magnitude of an attribute (such as population) in order to add visual contrast to the data and and show its distribution.

Prism Map

a type of map that shows the magnitude of an attribute by varying the heights of areas.

Dot Density Map

a type of map that uses dots to represent data values associated with a polygon. It is only used with polygons/areas. In dot density maps, each dot represents more than one feature, and the total number of dots within a polygon represents the polygon's data value

3D Perspective Map

a type of map that uses the vertical height of each cell in a fishnet to represent quantitative variables that vary smoothly across a surface

Continuous Surface Map

a type of map used to show quantitative variables that vary smoothly over a surface.

Topographic Map

a type of reference map showing topological features including terrain, water networks, boundaries, roads, towns, cities, as well as labels showing the names of important features.

Geoid

a vertical datum and a hypothetical Earth surface that represents the mean sea level, assuming Earth's surface is completely covered by water.

Atomic elements of geographic information

location (x, y), time, and other attributes. (time is optimal, location is essential)

Conic projection

map projection that projects Earth onto a cylinder by touching the earth on one line or intersecting the earth through two lines

Cylindrical projection

map projection that projects Earth onto a cylinder by touching the earth on one line or intersecting the earth through two lines

Planar projection

map projection that projects Earth's surface onto a flat plane by placing the plane at a point on the globe.

Conformal projection

map projection where angles on the globe are preserved (thus preserving shape) on the map over small areas

Choropleth Map

maps that represent quantitative properties of area features using lightness/intensity of colors

Flow Map

maps that show movement of things from one place to another using a line symbol with direction.

Graduated Symbol Map

maps that use symbols with various sizes to represent different groups of values, which means the quantitative values are grouped into intervals and all the features within an interval are shown with same sized symbol

Proportional Symbol Map

maps that use various symbol sizes to represent the value of the attribute mapped

Map projection

mathematical process of transforming a particular region of the earth's three-dimensional curved surface onto a two-dimensional map

Qualitative change map examples

non-urban to urban land use over time, dam destruction over time, location of volcanic plume over time

northing

north-south y-coordinate in a projected coordinate system

Volume Phenomenon

phenomenon that occupies a volume in space (including length, width, and depth) at the scale of the map.

Equidistant projection

projection that preserves accurate distances from the center of the projection or along given lines.

Equal-area/equivalent projection

projection that preserves the relative size of Earth's regions.

Nominal Data

qualitative data that has no order and thus only gives names or labels to various categories.

Interval Data

quantitative data that consists of numerical values on a magnitude scale that has an arbitrary zero point. Those numerical values can order from low to high with a numeric difference between the classes, but with no absolute value for the numbers and an arbitrary zero point.

Ratio Data

quantitative data that consists of numerical values on a magnitude scale. However, in contrast to interval-level data, the zero point is not arbitrary: there is a clear definition of the zero point. Typically, the zero point denotes absence of the phenomenon.

Ordinal Data

quantitative data that includes values with order, which allows comparisons of the degree between two values.

Datum

reference system for plotting locations on a map, can be a horizontal or a vertical model

Compromise projection

rojection that maintains a balance between distortions of shape, area, distance and direction, rather than perfectly preserving one geometric property at the expense of others.

Ellipsoid

shape of the earth, larger radius at equator

biggest advantage of the Cartesian coordinate system

simplifies locating and measuring

order of UTM coordinate system

six-digit integer is the easting x-coordinate in meters, seven-digit integer is the northing y-coordinate, zone number and hemisphere

visual variables for qualitative maps

size, pattern texture, color lightness/color value, and color saturation/intensity

Geographic attributes

specific statistics tied to geographic location, e.g., Population density, Tax rates, Health data (lung cancer rate), Temperature, Air pressure.

Mimetic Symbol

symbols that imitate or closely resemble the thing it represents using simple designs, e.g. an icon of a picnic table to represent a picnic area

Pictographic symbol

symbols that look similar to the real-world features they represent

Geometric symbol

symbols that use simple shapes, such as squares, circles, and triangles to represent different features

longitude

the angular distance of a place east or west of the meridian at Greenwich, England, or west of the standard meridian of a celestial object, usually expressed in degrees and minutes. 0-180 degrees

Easting

the east-west x-coordinate; defined as the distance from an origin in a projected coordinate system

Geodetic datum can be defined by specifying:

the ellipsoid, the coordinates of a base point, and the direction north

Universal Transverse Mercator (UTM)

two-dimensional Cartesian coordinate system to give locations on the surface of the Earth

Geographic coordinate system,

uses three-dimensional spherical surface and measures latitude and longitude to define locations on earth

three major geospatial technologies

GIS, GPS,RS

What unit of measurement are UTM bands measured in?

Kilometers

Types of maps

Reference, thematic, navigational, and persuasive

How do we represent geographic information?

Through maps

What map projection does UTM use?

Transverse Mercator projection, which is a cylindrical projection

Tissot's Indicatrix

circles used to visualize distortions due to map projection. These circles are equal in area before projection, but distorted afterwards

visual variables for quantitative maps

color hue, orientation, and shape

Projections by type of geometric distortions

conformal, equivalent, equidistant or compromise

Projections by shape of surface

cylindrical, conical or planar

Quantitative Data:

data that portrays the magnitude (e.g., size, importance) of things, expressed in numbers.

Discrete Data

data that represent distinct boundaries. These phenomena/objects usually belong to a class (e.g. soil type), a category (e.g. land-use type), or a group (e.g. political party), which have definable boundaries.

Qualitative Data:

data that shows the categories of things expressed by means of a natural language description (e.g. words) or sometimes numbers which have no numerical meaning (e.g. basketball jersey numbers).

Continuous Data

data which has no defined borders, but which has a smooth transition from one value to another.

Does the length of a degree of longitude increase or decrease from the equator to a pole?

decrease

What is geospatial technology

describes the use of a number of different high-tech systems and tools to acquire, analyze, manage, store, or visualize various types of location-based data