Mapping & GIS Mid-term Flashcards

Terms Definitions
What is a map?
A bird's eye view of all the earth's surfaces and or a concrete or abstract representation of the features that occur on or near the surface of the earth or other celestial bodies.
What is cartography?
The art, science and technology of making maps, together with their study as scientific documents and works of art.
What is a mental map?
Images we have in our minds.
Computer-assisted Cartography is:
Applying computers to the processing and analysis of remote-sensing data and operation of geo-graphic information systems and then to the production of maps.
What is part of almost all maps?
Typographical information including titles, legends, names and notes.
What is a title
Map Subject, Time period of map, other content aspects
What is in a legend?
map symbols and their explanation
What is a neatline?
A narrow line that frames the map area.
What is the scale?
The ratio between the size of features on the map and the size of the same features on the ground. It can be a representative fraction, a word statement or a graphic scale.
Orientation
The way a map is aligned relative to the earth's surface. See North arrow.
Inset
Additional small map with larger map. It can be 1) An enlarged portion 2) Locator map, 3) Areas related to main map, 4) Additional information.
Locator map
One that shows where the map is found in a larger, better know region. (Can be an inset map.)
Supplemental inset
Can be treated as individual map with it's own legend, scale, direction and other features.
Planimetric map
Maps that do not show relief features in measurable form. Usually the simplest form of map.
Planimetric base map
Used to provide framework for thematic maps.
Outline map
Outlines that provide a framework for plotting information - like empty U.S. map with just rivers and lakes.
Cadastral map
Usually includes the location of property-ownership lines, with their bearings and lengths, the ownership and size of land parcles and similar information - think platt maps.
Line route maps
Specialized maps used by utility companies to show routes and right of ways of their transmission lines or pipelines. (Cadastral map)
Topgraphic map
Shows the shape and elevation of terrain. (Greek topos = place & graphien = to describe)
Bathymetric maps
Water depths and the configuration of underwater topography.
What is an engineering map?
Detailed Maps, sometimes called plans, used in engineering projects and to aid in estimating construction costs.
Flood-prone area maps
Provide information about areas subject to flooding. Derived from topographic maps.
Landscape Map
provides detailed site information and planting plans for gardens and parks.
Thematic Maps
Show information about any of a myriad of special topics superimposed on a base map.
Dot-distribution maps
A thematic map in which dots are used to represent a specific quantity of a particular variable.
Choropleth map
A thematic map that shows distributions summarized on the basis of areas delimited by state or county boundaries or other arbitrary boundary lines. (Each ara is colored, shaded, dotted, or hatched to appear as a darker or lighter tone.)
Isoline maps
Show numerical values for continuous distributions by means of lines joining points of equal values.
Thematic Flow maps
show direction and amount of movement, as well as the types of goods or services moved.
Cartograms
Cartograms are a deliberately distorted unique representation that substitute a different standard of measurement (time or cost) for the distance or area measurements customarily used.
Remote sensing
gathering information by means of a sensor that is not in contact with the objects in the scene being observed.
Aerial photographs
The most common remote sensing product.
Vertical aerial photograph
Taken with the lens pointed straight down at the ground.
Oblique aerial photograph
Taken with the lens pointed at an angle away from the vertical.
Radar image
A remotely sensed product where a special transmission is beamed from a power source and reflected energy is captured and converted into an image of the scene.
Satellite images
can be taken fomr a spacecraft with or without a crew.
Earth
A sphere, by convincing and direct evidence such as astronauts.
Poles of rotation
Proving for a starting point of a locational system
Great Circle
The line defined by the intersection of a plane passing through the center of the earth and it's intersection with the earth's surface.
Lines of longitude or meridian
Each half of a great circle that joins the poles.
Prime meridian
The starting point - most maps use Greenwich England which then gets a value of 0.
Highest numbered meridian
180th, opposite the prime meridian
Equator
A great circle, placed at right angles to the meridians, and located midway between the poles.
Small circles
Parallel to the equator but the lines of latitude created by planes passing through the earth both north and south of the equator.
Hypsometric tints
Layered tints showing relief
Parallel
Lines of latitude, placed parallel to the equator
Graticle
The pattern of the meridians and parallels on the earth.
Parallels and Meridians
Cross each other at right (90*) angles.
Ellipsoid
Earth's shape due to it's revolving easterly and that generating centrifugal force whih causes the earth to bulge at the middle and flattern at the poles.
Polar Flattening
Earth's radius is slightly greater at right angles to the axis of rotation and slightly smaller along the the axis For earth, it's 1/298 or almost 0.
Geoid
An ellipsoid with a slightly irrregular shape caused by variations in the density of various portions of the earth's crust.
Eratosthenes
A Greek mathematician who first measured the earth in 250 B.C.
Summer Solstice
Whent the noon sun is directly overhead.
Geodetic Control Surveys
the curvature of the earth and determine locations in terms of latitude and longitude.
Polaris
The north star, which, when standing at the north pole, appears to be directly overhead. (Actually 1.5 degrees away.)
Astronomic latitude
measuring the angle between Polaris and the observer's horizon.
Chronometer
Extremely accurate clock
Magnetic Declination
The difference between the direction to the north magnetic pole and the direction to the geographic pole.
Analemma
A figure eight-shaped diagram which gives information about the latitudes at which the sun is directly overhead throughout the year. A visual picture of the equation of time. An analemma is usedto determine the equation of time on any given date.
Ephemeris
A set of tables that more exactly (then an analemma), provied information about the latitudes at which the sun is directly overhead throughout the year.
Plane of the eliptic
The imaginary plane that passes through the sun and the earth at all positions of the earth's orbit around the sun. Earth's axis tilts 23.5 degrees relative to a line perpedicular to the Plane of the eliptic.
Declination of the sun
What latitude the sun is over through the year - and is used to adjust the calculation when an observation of the sun is being used to determine the latitude of a point on the earth's surface.
Apparent Solar Day
The period between one noon and the next at the same location.
Mean Solar Time
Depending on the time of year, each solar day differs from one part of the year to another, therefore the mean solar time is 24 hours because it uses the average length of a day throughout the year.
Equation of Time
The difference between the mean solar time and the apparent solar time.
International Date Line
The 180th meridian, a 1/2 day away from the Prime Meridian.
Time zones
24 zones on earth, each 15 degrees. Earth rotates through one each hour. Central meridian of each zone is the time meridian.
Coordinated Universal Time (UTC)
The basis of times observed in each time zone. Formerly known as Greenwich Mean Time (GMT).
Deflection of the vertical
The difference at a given location between a vertical line drawn to the center of the earth and a verticl line drawn to the earth's center of gravity.
Geodetic Control Networks
From two starting locations determined by astronomical observations, using a system of triangulation, the surveyor is able to calculate the locations of newly observed points.
Monument
Plaque placed at a survey control point to designate location and/or elevation.
Trilateration networks (Historically more common Triangulation Networks)
Basing surveys on the measurement of distances, just as in Triangulation, they were based on the measurement of angles.
North American Datum of 1927
Historical basis of maps of North America, based on a vast control network originating at Meade's Ranch Kansas.
North America Datum of 1983
Now, standard reference for maps of continent. Recalculation of NAD of 1927.
Horizontal datum
Starting elevation to which elevations on a map are referred. Necessitated by today's engineering and scientific accuracy requirements and made possible by satellite observation methods.
Plane survey
A survey in which measurements and computations are made without considering the earth's spherical shape.
Differential leveling
Put a level between two points. Measure a rod above the known point, turn and meause a rod above the new point, the difference is it's elevation difference with the known point.
Datum
Fixed elevation, such as mean sea level, used as a starting point for a vertical survey.
mean datum
Vertical datum that averages long-term tidal variations. Max. accuracy is hour computations for 18.6 years.
Metonic cycle
The complete cycle of relationships between the sun, moon, and earth evolves over 18.6 years.
Stilling basin
Used to get mean sea level. Cut off from the direct influence of wind and waves.
Standard North American datum
Used in the U.S. and North America - adjusted in 1929 and in 1988. (NAD 1988)
Vetical Aerial Photographs
Used for mapping purposes and taken with an aerial survey camera. Typically 9 inches (23 cm) square.
Parallax
Difference in viewpoint of one eye versus the other, which results in a three-dimensional, stereoscopic image.
Stereo pairs
Overlapping photos which provide two slightly differing views of each portion of the earth's surface.
Stereoscope
Simple instrument that permits the simultaneous viewing of a stereo pair of aerial photographs so that the desired three-dimensional effect is achieved.
Stereoscopic image
Three-dimensional image (especially of aerial photographs) showing the same scene from slightly different points of view. Used for stereoscopic (three-dimensional) viewing.
stereomodel
Apparent three-dimensional view of the terrain, as viewed in a stereoplotter.
Ground control points
An easily identifiable point on the ground established to tie remote-sensing images to a ground survey.
Control diagram
Map based on a survey used to establish ground locations of control points for aerial photography.
Floating mark
In stereoplotter, point of light that appears to be suspended over the stereomodel. Used to transfer locational information
Globe
spherical model of the earth
gores
Tapered strip map used in globe construction.
perspective view
view of a scene from a single viewpoint, such as an aerial photograph.
Orthographic view
View drawn as though every point were seen from directly overhead, such as a map.
map projection
Systematic rendering on a flat sheet of paper of the earth's graticule (lines of latitude and longitude).
grid
graticule
plane
Flat surface used for azimuthal projections.
Developable surface
Projection surface, especially a cone or a cylinder, that is not flat at the time the projection is created but that can be flattened later.
gnomonic position
light source at the center of the globe
stereographic position
At the antipode (The point exactly opposite the point of tangency of the projection surface.)
Orthographic position
The light source at infinity
Orientation of a projection surface
May be changed as desired but certain orientations are normal.
Normal projection
Cylinder would be tangent at the equator. Cone would be tangent along a parallel with the apex above the pole. The normal orientation of a plane is tangent at the pole (Polar Azimuthal.)
Transverse projection
Turned 90* from normal. Tranverse Cylinder is tangent along a median. Transverse plane is tangent along the equator.
Transverse Conic
Apex of the cone on a plane of the equator.
Oblique projection
Results if the projection surface lies at an angle somewhere between normal and the transverse positions.
Standard line
The line of tangency between a projection surface and the surface of the globe. Alnong the standard line, the map has no distortion. (If along a parallel, can be called the standard parallel.
Secant projection
Projection in which the projection surface intersects the globe. (Cone or cylinder would have two standard lines. A tangent plane woud have one.)
Oblique azimuthal (plane)projection
Plane leaning along side of earth, not a polar tangent of an equatorial tangent.
Major Properties
Can exist at all points on certain projectes - Conformality & Equivalence
Conformality
The retention of correct angles on a map.(Can only occur in small areas.)
Equivalent (equal area) projection
Projection on which equal areas are retained, so that a unit area drawn anywhere on a map always represents the same area on the earth's surface.
Minor properties
Those that can exist in relation to only one or sometimes two points or lines on certain projections. Distance and direction
Great-circle distance
Shortest distance between two points on the earth's surface, represented by the path of a great circle.
Equidistant maps
Map with the characteristic of correct distance relationships.
Direction
The path along which something is moving or pointing.
True azimuth
Direction of a great circle. Also known as an orthodrome.
Compromise projection
Map projection that does not preserve any of the globe properties but also does not result in extreme distortion of any property.
Mercator
Conformal map projection that shows the world (less the polar regions) in a rectangular format. Useful for navigational purposes because all the straight lines drawn on it are lines of constant compass direction.(Scale distances become increasingly exaggerated away from the equator and toward the poles.)
Shapes of smaller, individual features are correct but not over large areas suh as continents. Used for navigational charts.
Sinusoidal projection
An equal area (equivalent) projection.Looks like a flattened tear drop with points. i.e. Albers equal-area (often for U.S. maps); homolographic; The Goode interrupted homolosine; the Bonne
Azimuthal equidistant projection
Map projection on a plane, in which all points are plotted at their true distance from the center of the projection and are in their true global direction (azimuth) from the center. Both poles bent to touch tangent. Preserves the globe quality of equidistance.
Gnomonic projection
Map projection on a plane, with the light source at the center of the earth. All straight lines drawn on a gnomonic projection represent portions of great circles. Used for navigational charts.
Interruption
Involves separating the projection along several dividing lines. such as equal-area projections.
Compromise Projections
1) The Miller Cyllindrical - Shows the world in a rectangular world. Modified from the Mercator so that it distorts the size of areas less.
2) The Robinson -Minimizes visually disturbing distortions. (Rounded belly)
3) The Winkel Tripel - Used by National Geographic. Based on the balance it provides between size and shape.
Lambert Conformal conic projection
Used for mid-latitude air charts because straight lines drawn on it very closely approximate great-circle routes.
Retaining correct shapes
Conformality
Retaining Equal-Area characteristics
Equivalence
Methods of specifying locational information
1) Latitude and Longitude Coordinate System
2) State Plane Coordinate (SPC) system
3) World Geographic Reference System (GEOREF)
4) Universal Transverse Mercator (UTM)
5) Universal Polar Stereographic (UPS) systems
Land-partitioning systems
1) Metes and Bounds : Unsystematic
2) U.S. Public Land Survey (Canada Land Survey System - CLSS) USPLS
Interpolation
Method of logically determining the elevationof a point that is not on a contour or a spot height. Althernatively, method of determining the coordinates of a point not located on a grid or graticule line.
Grid ticks
Short lines to indicate the intersection of the graticule with the map outline (Called a neatline.)
Spacing dividers
Eleven-point dividers used for measuring interpolated locations.
World Geographic Reference System (GEOREF)
Allows more convenient and rapid reporting and plotting of locations.
Plane Rectangular Grid (reference grid)
System of lines superimposed on a map for locational purposes that does not take the curvature of the earth's surface into account.
Cartesian Coordinate System
Four-quadrant system of locational coordinates
General rule for plane coordinate systems
Locations are defined by giving the east-west coordinate first and the north-south coordinate second.
Universal Transverse Mercator (UTM) System
Plane rectangular grid system that covers the earth's surface between 80* South and 84* North. Used in conjunction with the Universal Polar Stereographic (UPS) System, which covers the polar caps. Civilian system that uses only numbers, while the US Military Grid Reference System uses number/letter combinations to designate grid zones. 60 north/south zones, each 6 degrees wide. Each zone overlaps the other zone by 1/2 degree.
Military Grid Reference System
Military version of UTM/UPS Systems - Avoids long strings of numerals. 84* North to 80* South, divided into grid zones 6* east/west by 8* north/south. Each grid has column number and row letter. Column numbers are 1 - 60. Row letters are C - X omitting I and O. i.e. 3N AND, Polar Grid Zones are A/B for south and Y/Z to north.
State Plane Coordinate (SPC) System
Rectangular coordinate system individuallyapplied to each of the United States. Each state is split into zones. With exceptions, the Lambert conformal projection is used for east/west trending states and the transverse Mercator is used for north/south trending states.
Cadastral surveys
Survey used to determine land-ownership boundaries and property descriptions. In the United States, preferably reserved for land-ownership surveys of the public lands.
Unsystematic subdivision
Land-ownership pattern developed in an unplanned manner, using, for example, property boundaries established on the basis of settler's claims. (Mostly colonial U.S.)
Metest and Bounds surveying
Method of land survey used to describe unsystematic land ownerships. Records the direction and length of each portion of the boundary line of the property in sequence, often using distinctive markers, such as trees of particular species.
Bearing
The angular difference between a north or south reference and the direction of the surveyed line. (i.e. north 45* east)
Rectangular Survey System
Method of land survey, utilizing townships and ranges. Started in Ohio and ultimately extended throughout most of the western states and parts of the south. Originally known as the rectangular survey system. Now knows as the Public Land Survey, U.S. (USPLS, systematic subdivision)
Principal meridian
North-south reference line used in a US Public Land Survey Zone.
Baseline
Line that serves as the basis for a survey, with endpoints, direction, and lengths that are accurately known. Or east-west reference line used in conjunction with a U.S. Public Land Survey principal meridian.
Townships
Six-mile-wide, east-west zone in the US Public Land Survey and Canada Land Survey System. Also, 36-square mile area formed by the interesection of an east-west township and a north-range.
Ranges
The north-south lines in the grid form columns.
Sections
Townships formed by township rows and range columns are subdivided into thirty-six sections, each about 1 square mile (640 acres), their exact size of actually surveyed townships often differs from the standard.
Township plats
Detailed map of the land-ownership boundaries within a US Public Land Survey township.
Aiquot parts
Division of a US Public Land Survey section into various combinations of quarters (160 acres), quarter-quarters (40 acres) and halves (80 acres).
Lot
In US Public Land Survey, subdivisions used when the normal system of fractional sections cannot be applied, such as along the northern and western edges of some townships or along the shores of navigable streams or lakes 25 acres or more in extent.
Meander line
In the US Public Land Survey, line surveyed along the mean high-water elevation of a navigable water body. (High water lines are used to establish property boundaries.)
Standard parallel
In the US Public Land Survey, east-west reference line established at 24-mile spacing. In normally oriented conic or cylindrical map projections, parallel of intersection of the project surface with the globe.
Guide meridians
In the US Public Land Survey, north-south reference line established at 24-mile spacing.
Seigneury
Seventeenth cerntury French land grant in the region that is now Quebec and the Maritime provinces except Newfoundland. Granted for the purposes of promoting settlement and development.The land holders were called seigneurs.
Rotures
Lot allocated to an individual farmer in the seigneurial land ownership system of French Canada.
Canada Land Survey System (CLSS)
Survey system established in 1870 to provide an orderly land-ownership framework in the prairies and mountains of western Canada. uses principal meridians and baselines, townships, ranges, sections, and subdivisions of sections.
Legal Subdivision
In the Canadian Land Survey System, division of a section into sixteen 40-acre subdivisions, which are equivalent of quarter-quarter sections in the US Public Land Survey.
Scale
The ration between map distances and earth distances. Can be expressed as a 1) Word Statement; 2) Arithmetic ratio (representative fraction), or 3) a graphic symbol.
Word Statement
Statement of scale ratio in words.
Representative-Fraction (RF) scale
The ratio between the map distance and the ground distance between equivalent points.
US Customary Units
Units of measurement, such as feet, inches, and miles, based on the units of the older English system.
foot
Unit of measuremnt in the US Customary system, defined as 1:0.30480061 meter. Since 1959, also know as the US Survey foot.
international foot
Defined as 1:0.3048 meter. Compare with US Survey foot. (See foot)
Mile
Unit of measurement in the US Customary system. Defined as 5280 feet (1069.35 meters)
metric system
System of measurement originally defined by the French Academy of Sciences in 1791.
meter
Basic unit of measurement of the metric system. Originally defined bas one ten-millionth of the great circle from the earth's equator ot the earth's pole. Since 1983, defined as the distance that light travels in 1/299,792,458 of a second.
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