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