Geology 170- Final Exam

DMS to DD

D + M/60 + S/3600

coordinate system

"a reference system which uses one or more numbers, or coordinates, to determine and represent the locations of geographic features, imagery, and observations such as GPS locations within a common geographic reference framework." --- ESRI Coordinate systems (either geographic or projected) provide a framework for defining real-world locations. There are two ways to pinpoint locations on maps: Geographic Coordinate System (latitude, longitude) (covered in more depth below) Projected Coordinate System (x, y) (covered in more depth in Lecture 4): a projected coordinate system provides a mechanism to project maps of the earth's spherical surface onto a two-dimensional Cartesian coordinate plane.

Scale Bar

"graphic scale" -a bar or line to represent a scale. -It is usually divided into several segments. -It is a graphic ruler printed on the map. -straightforward, easy way to determine distances on a map -a scale bar changes size in proportion to the physical size of the map -both metric and imperial units

LORAN

(long-range navigation) has been used for marine navigation. LORAN uses radio signals from multiple transmitters that are used to determine the location and speed of the receiver. It is good for sailing, but its utility is limited within coastal areas.

UTM zone

- numbered from 1 to 60 starting from 180° longitude at the International Date Line and proceeding eastward. --Therefore, Zone 1 lies between the 180°W to 174°W longitude lines and is centered at 177°W; Zone 2 is between 174°W and 168°W longitude. Zone 60 covers longitude 174°E to 180°E. -Each zone is also formatted with an "N" or "S" after the zone number, indicating whether the zone is in the North or South hemisphere.

Azimuthal or Zenithal projection

-Directions from a central point to all other points are maintained accurately (also known as zenithal or true-direction projections). These projections can also be equal area, conformal or equidistant at the same time.

transitioning between scales

-In a paper map, the scale is FIXED. -In a computer-based map or a web-based map, the scale is DYNAMIC and changeable.

Mercator projection

-It is Eurocentric, and it places the northern hemisphere on top, encouraging thinking of the northern hemisphere as dominant. -It distorts the polar regions, including the northern parts of the globe (giving a false sense of size to small northern countries). The best example of the distortion can be seen in Greenland. On this map Greenland looks larger than South America, while as a matter of fact, it is closer in size to Mexico. Also while Africa is about 14 times larger than Greenland, on this projection the two appear to be the same size.

How can we calculate Map Scale?

1) Measure the distance between any two points on the map. This distance is the map distance (MD). 2) Determine the horizontal distance between these same two points on the ground. This distance is the ground distance (GD). 3) Use the representative fraction (RF) formula, and remember that RF must be expressed as: RF = 1 / x = MD / GD

GPS gets the position of the receiver in three steps

1. Satellites send signals containing location and time to the GPS receiver. 2. The GPS receiver searches and obtains signals from at 3.least three satellites. The more satellites it finds, the higher accuracy it can achieve. The GPS receiver a) calculates its distance to the satellites, and b) determines its location using the method of "trilateration".

distance between satellite and reciever

Distance = time delay * speed of light

great circle

A prime meridian and its opposite meridian at at 180° longitude -curved path that is the shortest distance between two points measured on a sphere

Timing

GPS brings precise time to us all. GPS satellites carry an atomic clock that contributes very precise time data to GPS signals. The accuracy is measured in nano seconds, which is 100 billionths of a second.

Mapping

GPS can also be used to create maps by recording a series of locations as well as useful information. This function is used by scientists to collect field data, as well as by industrial and governmental bodies in making geospatial policy

Equivalent (equal area) projection

A projection that preserves the relative size of regions -are used in maps that show data that depend on accurately displaying an area's size. -Sinusoidal projections are often used in countries whose territory extends further in the north-south direction than the east-west direction.

Locating

GPS is the first system that can give accurate and precise location information anytime, anywhere and under any weather conditions. Some examples are: Measuring the movement of volcanoes and glaciers. Measuring the growth of mountains. Measuring the location of icebergs - this is very valuable for ship captains to avoid possible disasters. Storing the location of where you were - most GPS receivers on the market will allow you to record a certain location. This allows you to find these points again with minimal effort and is useful in hard-to-navigate areas such as dense forest.

latitude of origin

The origin for northings in each zone is a parallel just south of the counties in the zone

Conformal Projection

When angles on the globe are preserved (thus preserving shape) on the map over small areas -navigational or meteorological charts. - Examples are Mercator and Lambert Conformal Conic. The U.S. Geological Survey uses a conformal projection for many of its topographic maps.

Differential GPS

a correction method that uses a series of base stations at known locations on the ground to provide a correction of GPS positional information.

geoid

a hypothetical Earth surface that represents the mean sea level (MSL) -vertical datum and a hypothetical Earth surface

Map projection

a mathematical process of displaying a particular region of the earth's three-dimensional curved surface onto a two-dimensional flat map. A good globe can provide the most accurate representation of the Earth.

control segment

a set of ground stations for monitoring, tracking, and correcting those signals - control stations that track and monitor the signals being transmitted by the satellites. These control stations are spread out to enable continuous monitoring of the satellites.

Projection Surface

a simple geometric form capable of being flattened without stretching, such as a cylinder, cone, or plane. Projections classified by surface -Cylindrical -Conical -Planer (Azimuthal) can be classified based on DISTORTION

Remote Sensing (RS)

a technology that is used to acquire imagery go the Earth's surface though the use of satellites or aircraft - satellite imagery, aerial photos -visual info with out physical contact

Global positioning System (GPS)

a technology that requires real-time location information from a series of satellites in Earth's orbit

Mosaicking

after capturing a series of photos, we can merge those small tiles into one big aerial photo.

Navigation map

also called the 'navigation charts,' are maps created specifically to help the navigator plan and follow a travel route. include: Nautical charts: created specifically for water navigation. Aeronautical charts: designed for the air navigator filling with information important to safe flying.

Geodetics

also known as Geodesy, is the science of determining the actual size and shape of the earth. It covers the theories and technologies of measuring the precise location and motion of points on the earth's surface using various instruments, such as GPS, total station, and theodolite

Aerial Photos

are obtained by flying aircraft along flight lines (the paths that the aircraft follow), north-south or east-west (Figure 4). Photos are taken along straight flight lines with 60% to 80% overlap, that is each individual photo overlaps its neighbor by 60-80%.

longitude

called meridians, run perpendicular to lines of latitude, and all pass through both poles.

atmospheric conditions

causes inaccuracy particles alter signals

satellite clocks

clock and receiver very important -need to know precise time -need to synchronize the receiver's clock with the satellites clock

Real estate

compare housing prices, poverty in location to schools, highways, and waste water treatment

User Segment

composed of all GPS devices that receives its signals, like your smart phone, car navigation

Geographic Information System (GIS)

computer-based geospatial technology for storage, analysis and management of location- based data - both database for managing geospatial data as well as operations for working with the data

Geomatics

consists of the science, engineering, and art of gathering, analyzing, interpreting, distributing, and using geographic information. -GIS -GPS -RS

Space Segment

constellation of satellites for broadcasting positioning signals - These signals contain information about 1) the position of the satellite, and 2) the precise time at which the signal was transmitted from the satellite.

Cartesian Coordinate System

defined by a pair of orthogonal (x, y) axes drawn through an origin (Figure 1), where the origin (0, 0) is at the lower left of the planar section. -simplifies locating and measuring

Thematic Map

depict information on a particular topic. Is also called the "statistical map", or "single topic map" Examples: Weather, population density, and geology maps

public health

disease monitoring, tracking the source and spread of diseases and mapping health-related issues

Compromise Projection

don't try to perfectly preserve geometric properties; instead, they strike a balance between distortions, or simply make things "look right." Most compromise projections distort shape in the polar regions more than at the equator Example: Robinson Map -minimizes distortion -built on trial- and error with the goal of being usually appealing -has some distortions in shape, area, distance, and direction

ellipsoid (spheroid)

earth as a sphere. slightly larger in radius at the equator than at the poles -earth isn't perfect sphere, its lumpy -many different used for different regions of the globe

origin

established to the west and south of the zone, usually 2,000,000 feet west of the central meridian for Lambert conformal conic zones and 5,000,000 feet west of the central meridian for Transverse Mercator zones. Again, this is to prevent negative coordinate values

forestry

forest monitoring, managemant, and protection

Archeology

geospatial tech to pinpoint the location of artifacts

geographic information

has to do with Earth, its two dimensional surface, or its three dimensional atmosphere, ocean and sub-surface example: altitude of planes in the atmosphere

Spatial Information

has to do with any multi-dimensional frame or reference example: medical images referenced to the human body

Geospatial technology

high-tech systems and tools that can acquire, analyze, store, manage, and visualize various types of location-based data

What is Geospatial Information?

information that has location (x,y) component as well as other associated attributes or characteristics

prime meridian

is a meridian, i.e. a line of longitude, at which longitude is defined to be 0°. Unlike an equator, a prime meridian is arbitrary: there is no obvious 0-degree point for longitude. -Earth divided equally into 360 degrees of longitude - East of the prime meridian, longitudes are given positive values up to 180 degrees - West of the prime meridian, longitudes are given negative values up to 180 degrees

Equator

is an imaginary line (circle) that divides the Earth into Southern and Northern hemispheres, and it is an equal distance from both poles -has a value of 0 degrees latitude

vertical datum

is technically an arbitrary surface of zero elevation. Allows height measurements of various points be in a consistent system. More broadly, is the entire system of the zero-elevation surface as well as methods of determining heights relative to that surface.

Latitude

is the angular distance between the Equator and points to the north or south on the surface of the Earth. Line connecting all points with the same latitude value is called a line of latitude

Lambert Conformal Conic Projection

is used for states of predominantly east-west extent. For example, Colorado is a Lambert state with three zones.

Tranverse Mercator Projection

is used for states of predominately north-source extent, such as Arizona and New Mexico.

Trilateration

is used to determine exact position. In order to perform Trilateration, signals from at least 3 satellites are required. However this only gives you the horizontal location of a point on the Earth's surface, and this is called a two-dimensional fix (2D fix). Most of the time, a fourth satellite is used to improve the accuracy and help to provide a three-dimensional fix (3D fix), which includes elevation. In order to understand trilateration, let's start by looking at a simpler version - 2D trilateration.

Tissot's Indicatrix

is used to visualize projection distortions using circles. Before being projected, the circles are uniform in area and shape, but show distortions afterwards.

State Plane Coordinate (SPC)

made to make distinguishing borders easier - US divided into 124 zones

Reference Map

map that emphasizes the location of spatial phenomena. Have a primary purpose of summarizing the landscape to aid discovery of locations. Therefore, the Geographic features are depicted as detailed and spatially trustful as possible. Examples: Road maps, Google maps, Bing Map, mapquest.com, Openstreemap.org, USGS Topo maps

Persuasive Map

maps intended to convey an idea rather than communicate geographic information. mapmakers deliberately try to persuade you to choose a particular product or support a certain argument. image: what is your state worst at

Enviromental Monitoring

monitor and analyze the processes that affect Earth's enviroment -mapping climate changes, pollution

Peters projection

more "accurate" than mercator perserves relative area - Greenland is about the right size. - Alaska is correctly displayed as similar in size to Mexico.

GPS has five major functions

navigation, location, timing, mapping, and tracking (NLTMP) (nails like toes mani pedis)

multipath errors

occur when GPS satellite signals reflect off surfaces (trees or buildings)

planar projections

projects the Earth onto a plane by placing the plane so that it touches a point on the globe; the plane may be either tangent or secant. The point of contact is called the focus, which defines the type of planar projections into three classes: Polar planar projection - the focus is located at one of the poles Equatorial planar projection - the focus is located at any point along the equator Oblique planar projection - the focus is located at neither a pole nor along the equator

cylindrical projection

projects the spherical Earth onto a cylinder. The cylinder may be either tangent (touching the Earth's surface) along a specific line, or it may be secant (intersecting the Earth by passing under the surface) along two lines

Who uses Geospatial technology?

public health, federal law, biology, environment

geodetic datum

reference baseline for positions and mapping. We can reference latitude and longitude positions and elevation on a given ellipsoid. Can represent the SHAPE and SIZE of the Earth. defined by specifying: -the ellipsoid -the coordinates of a base point -the direction north can be horizontal or vertical

small scale maps

show a large area with few details

large scale maps

shows a small area with more details

Dymaxion Map

shows world as continuous land mass

GPS consists of 3 components

space segment, control segment, and user segment

What is a map?

spatial representation of the geographic information that is presented graphically. The job is to describe spatial relationships of specific features that the map aims to represent. These features can be political boundaries, population, physical features, natural resources, roads, climates, elevation (topography), or economic activities.

attributes

spatially dependent variables

single parallel projection

tangential to the globe along one line of latitude (the standard parallel).

map generalization

the elimination of map detail as the scale decreases

Selective Availability

the intentional degradation of GPS signals by the U.S. military. SA was turned off in 2000.

Navigation

the process of getting from one location to another. This is what GPS was designed for: it allows us to navigate on water, air, or land. It allows planes to land in the middle of mountains and helps medical evacuation helicopters take the fastest route.

secant conic projection

two lines of contact and, therefore, two standard parallels.

geographic coordinate system

uses a three-dimentional spherical surface and measures of latitude and longitude to define locations on the Earth. example: Google Earth -degrees, minutes, and seconds (DMS) -decimal degrees (DD) -degrees and minutes (DM)

Global Posistioning System

was devised and implemented in the early 1990s. GPS is also called NAVSTAR (Navigation System, Timing and Ranging), which is the official U.S. DOD name for GPS. It is a satellite-based navigation system with global coverage (GNSS) and can provide accurate positioning 24 hours a day anywhere in the world. Right now, GPS is provided free of charge by US.

McArthur Universal Corrective Map

was made by an Australian who was tormented for coming from the "bottom of the world." It was the first modern south-up map, published in 1979. This map has a unique viewpoint with cheeky Aussie humor.

graticule

what the parallels and meridians of latitude and longitude form on the globe -grid of orthogonal lines -used to show location in geographic coordinates (degrees of latitude and longitude).

UTM limitations

-Suitable for medium-scale mapping but not national-level -Designed for areas with N-S extent, and thus not good for areas with a large E-W extent (good for areas that are taller than they are wide) -Distortions are relatively small, but still may be too large for specific purposes like high-accuracy surveying. -Distortions become especially problematic at high latitudes; this is part of why Canada, with giant swaths of arctic territory, uses a Lambert Conformal Conic projection suited for mid- to high latitudes -UTM coordinates will differ when different datums are used Zone boundaries follow meridians instead of political or natural boundaries. Thus, it usually takes more than one UTM zone to cover a state or country completely. For example, Wisconsin falls into Zones 15 and 16 (Figure 4).

UTM coordinating system

-a six-digit integer as an easting value, followed by a seven digit integer as a northing value. -The first six-digit integer is the easting x-coordinate in meters -The second seven-digit integer is the northing y-coordinate in meters -The third value is the zone number and hemisphere example: the location of the State Capitol Dome in Madison, Wisconsin, in UTM is: 305,900m E, 4,771,650m N, Zone 16 North

Universal Transverse Mercator (UTM)

-a two-dimensional Cartesian coordinate system to give locations on the surface of the Earth. -It extends around the world from 84oN to 80oS. - not a single map projection. The system instead divides the Earth into 60 North-South zones covering the earth from East to West. Each zone has a central meridian, and covers a six-degree band of longitude.

Why do we use GPS?

-accurate posistioning -destinations -tracks or target of interest -cheap

conical projection

-cone shape -a cone could either be tangent to the Earth at a single parallel, or secant at two standard parallels. We refer to the parallels that touch or intersect with the Earth as standard parallels. advantages: -good for polar regions -good for aeronautical maps because it shows latitude in the form of a circle -. Conic projections are used in the U.S. and other large countries with territory that stretches more in the east-west direction than in the north-south direction.

geometric distortion

-conformal -equivalent -equidistant -compromise

Law enforcement

-crime locations plotted using GIS -analyze crime patterns and determine potential crime spots

Map Scale

-expresses the relationship between distances on the map and their corresponding ground distances. -measurements made on a map can be converted to ground units

Northing (UTM)

-he north-south y-coordinate in a projected coordinate system. In the northern hemisphere, a northing value of 0 m is assigned to the equator. Since no false northing value is added, a UTM northing value for a zone in the northern hemisphere is the number of meters north of the equator. In the southern hemisphere, a false northing of 10,000,000 m is given to the equator so that all northing (y-axis) values are positive numbers.

What makes a projection good?

-perserve area -perserve shape -perserve direction -perserve distance -minimizes distortion -must meet the purpose of a map

Equidistant Projections

-preserve accurate distances from the center of the projection or along given lines. It is usually used in air and sea navigation charts for navigation, as well as radio and seismic mapping. -distortion of other properties increase away from the center point

Representative Fraction (RF)

-the ratio between distance on the map and actual ground distance. -can be written in the format as either 1/x or 1:x , where the numerator is always 1 and the denominator (x) represents distance on the ground. e.g., or 1:50,000 1 to 50,000. This means that one unit on the map equals 50,000 units on the ground.

Transit

-used by U.S. navy -which determined the location of sea-going vessels with satellites. The drawback of Transit was that it didn't provide continuous location information—you would have to wait a long time to locate your position rather than always knowing where you were.

Verbal Scale

-uses words to describe the ratio between the maps scale and the real world 1 inch to 2 miles 1 inch equals 2 miles 1 inch = 2 miles

Easting (UTM)

-varies from near zero to near 1,000,000 m. In both the northern and southern hemispheres, the center line (central meridian) of each zone has an easting value (x values) of 500,000 m to ensure that there are no negative values -This value, called false easting, is added to all x-coordinates so that there are no negative easting values in the zone. Since this 500,000m value is arbitrary. eastings are sometimes referred to as "false eastings".

based on lighting source- planar projection

Gnomonic projection: "light source" at the Earth's center (Figure 10, B) Stereographic projection: "light source" located opposite the focus (Figure 10, C) Orthographic projection: "light source" from an infinite distance away, also known as the "view from space" (Figure 10, D)

Tracking

Tracking is a way of monitoring people and things such as packages, or moving vehicles. This has been used along with wireless communications to keep track of criminals and parolees. A convict agrees to keep a GPS receiver and transmitting device with him at all times. If he goes where he's not allowed, the authorities will be notified.