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213 Cards in this Set

  • Front
  • Back
geocentric view
orienting yourself with respect to the external environment
cardinal directiosn
N S E W
meridian
north south lines
cartographic map
graphic representation of the environment
5 characteristics of a map
vertical or oblique views of the env
created at a reduced scale
map projection-change spherical to fit flat
generalized representations
symbolized representations
topographic map
shows elevations and landforms
orthophotomap
topographic with photo superimposed
aerial photograph
not a map projection surface,only a photo showing scale and elevation differences
reference map
maps that serve as a reference library of geographic informatoin
thematic maps
tell an essay about a particular subject in the geospatial context
propaganda maps
persuasive maps that distort information
map use
the process of obtaining useful infomration from one or more maps to help you understand the environment and improve your mental map
3 main activities of map use
read
analyze
interpret
parallels
e to w lines
lat and long are measured by
the angular distance of a parallel from the equator and a meridian from the prime meridian
Tropic of cancer and capricorn
cancer (north hemisphere)
capricorn (southern hemisphere)

where the sun is directly overhead on the summer and winter solstices
graticule
arrangement of parallels and meridians
numerical range for latitutde
0 to 90
numerical range for longitude
0 to 180
babylonian sexagesimal system
uses degree, minutes, and seconds to pinpoint location

60 minutes a degree
60 seconds a minute
decimal degree system
does not use NSEW

equation:

dd+ mm/60 + ss/3600

dd = degrees
mm = minutes
ss = seconds
Where is the prime meridian located
in greenwich, a suburb of london
equation for centrifugal force
m*v^2*d
semiminor and semimajor axis
minor - N to S axis sliced in half
major - E to W axis sliced in half
geodetic latitude
angle made by the equator and a line perpendicular to the parallel of interest on the ellipsoid of the earth
equitorial and polar radius
equitorial - 6378.137
polar - 6356.75231
geodetic longitude
angle between the line from a point on the surface to the center of the earth to the prime meridian
authalic sphere
a sphere with the same SA as the reference ellipsoid being used
statute miles vs nautical miles
statute are used on land
equation for converging meridians
69.09 miles / deg. x cosine (lat)
great circle, small circle, quadrilaterals
great- larger circle on ellipsoid
small- when you have overlaps with another circle
quadrilaterals- bound by equal lat and long
control points
points on a map of known accuracy
monument
a fixed object established by surveyors where they know the exact location
why do we treat the earth as smooth when it is authalic or oblate
because the mountains and trenches are relatively small in comparison to the diameter of the earth
rules for sig figs for if rounding with a 5
round up for odd, for even stay the same (round down)
rules for sig fig addition
decimal in the place of the one with the least amount of sig figs
scale denominator
has a one in the numerator and the "scale denominator" in the denominator
map scale
tells you the relationship between distances on the map and their corresponding ground distances.

gives you an idea of how small the map is relative to real life
representative fraction
ratio between the map and ground distance

shown as 1:x

x = scale denominator
why would a scale bar be extended to the left past 0?
to show smaller units
on what type of map projection will you see a variable scale bar
mercator map projection
what is the typical dividing point between large and small scale maps
1:500,000

1 inch represents 500,000 inches
conversions that need to be known
1 foot = 12 in
1 statute mile = 5280 ft
1 statute mile = 63,360
1 km = 100,000 centimeters
length of the equator in miles
24901.46 miles
actual scale
the scale that you measure at any point on the map; it will differ from place to place because of geometric distortion
principal scale
the scale of the globe as it is reduced to its desired size
scale factor
actual scale / principle scale
completeness
ability of a map projection to show the entire earth
continuity loss
when a sphere is broken to be represented as a flat image. At one meridian , it will be represented twice on either edge of the map
conformal
when angles on the globe are preserved on the flat map
true direction projections
projections that preserve global directions
azimuth
direction from a reference point
projection families
planar, clyindrical, and conic

*imagine a light radiating from the earth and projecting a shadow of the landforms of the earth
three perspectives for planar projections
orthographic (light source at infinity)
stereographic (light source on the surface of the globe opposite to the pooint you are looking at)
gnomonic (light at center of globe)
tangent case projection
the projection surface will only touch the globe at one point, or along one line (this is the case for a cone)
secant case projection
the projection surface intersects the globe at a small circle of tangency
advantages to secant case
there is less distortion
what are tangent projections used for
equidistant projections usually
aspect
location of the point or lines of tangency on the projection surface
equitorial aspect
when the projection line is on the equator
transverse aspect
used with cylindrical projections to refer to when the line of tangency is shifted 90 degrees to follow a pair of meridians

*tube turned horizontal instead of vertical
oblique aspect
an aspect that is not polar, equitorial, or transverse
orthographic projection
shows the earth as how it looks from a distant planet
stereographic projection
light source from the antipodal point of the globe

usually used for polar views
what is a gnomic projection used for
navigation for great circle routes
seismic and radio waves
Mercator map is projected how
cylindrical conformal projection
benefit of a mercator map
that it is good for compass bearings
what is the difference between a map and a cartographic map
a map is a spatial representation of an environment, while a cartographic map is a graphic representation of an envrionment
what makes maps popular
convienient to use
simplify our surroundings
credible
strong visual impact
3 different types of maps
reference, thematic, and navigation
Ex of reference maps
topographic map of Oregon, globe, road map
Ex of thematic maps
ones that will show a piece of information, such as demographic information, spread out over spatial map
Ex of navigation map
topographic maps, nautical charts, and aeronautical maps
three ways to represent scale
representative fraction
verbal scale (a sentence)
scale bar
what is the difference between geocentric and geodetic coordinates
geocentric is using a sphere
geodetic is using an oblate ellipsiod
grid coordinate system
plane-rectangular system where the earth is projected to fit a flat surface and regularly space lat and long are used
cartesian coordinate system
uses x and y axis and quadrants for mapping
What does UTM stand for
universal transverse Mercator system
UTM extends through what latitude
84 N to 80 S
How many zones are in UTM and how much longitude is in each one?
sixty NS zones with 6 degrees long
what is an easting?
the E-W x coordinate in a grid coord system
what is a northing?
the N-S y coordinate
false easting values
easting = 500,000 m
how do you report in UTM
easting, northing, zone, hemisphere
What does UPS stand for
universal polar stereographic system
UPS system
does complete global coverage with the rectangle system as well.

has N and S zone

is imposed on secant polar stereographic projection
UPS grid center
2,000,000 mE 2,000,000 mN

no negative numbers
state plane coordinate (SPC) system
creates grids and zones to make selling parcels of land easier
SPC zone system
follow state and county lines

each zone has its own central meridian

uses ft instead of m
what is the difference between geocentric and geodetic coordinates
geocentric is using a sphere
geodetic is using an oblate ellipsiod
grid coordinate system
plane-rectangular system where the earth is projected to fit a flat surface and regularly space lat and long are used
cartesian coordinate system
uses x and y axis and quadrants for mapping
What does UTM stand for
universal transverse Mercator system
UTM extends through what latitude
84 N to 80 S
gnomonic projection
shows all great circle lines, the shortest location between two points is what is depicted on the map
azimuth
angular measurement on a spherical coordinate system
rhumb lines
lines of a constant compass heading
straight lines on a mercator projection represent
rhumb lines
straight lines on a gnomonic projection represent
great circles
loxodromic curve
the curve from following a rhumb line on a standard globe, spiral-like
what way do you measure great circl azimuths
intersections with meridians, going clockwise
mercator projections have constant
compass bearings
quadrilaterals
areas bound by the same lat and long increment
aspect ratio of quardrilateral with increasing latitude
aspect changes to cosine (latitude)
SPC coordinates increase which way?
moving east and north
two ways of thinking of distance
physical distance- a measured amount in standard unit of distance

or

functional distance - distance measured at expenditure or cost, time, and energy
geographic mile
represents a fraction of a degree of the earths circumference

6087.1 ft
knot
velocity of one nautical mile and hour
a meter is defined relative to what
the speed of light
two major ways for finding distance on large scale maps
measure distance and compare it to a scale bar

use the representative fraction to convert the map distance to ground distance
how do the length of lines for distance measuring affect error
the shorter the line, the more accurate the distance measured
external errors
result from the methods you use, judgements you make, calculations, etc
internal errors
results from the nature of the map itself. such as trying to fit a 3D world onto a 2D projection
slope error
the fact that most measurements are made on a flat surface when the earth is not like that in reality

the greater the slope, the greater the slop error
smoothing error
maps may be smoothed by mapmakers to make lines straighter and remove irregularities
scale variation
no map projection maintains a constant correct scale throughout can lead to error
disproportionate symbol error
the size of a symbol is not proportional to its ground size (usually it is depicted larger in the proportion)
displacement
when features are spaced so that they don't visually run into each other, but, in fact, because of the disproportionate symbol effect, moving the objects for space distorts them from reality
dimensional instability
when the medium that the map is printed on changes

ex: paper can change its shape and size depending on if it is hot or cold
distance segments
premeasured ground distance that is place between road intersections to give real distance
distance insets
double ended arrows with names of features and the distances between them
mileage map
routes between highlighted locations are shown as straight lines and labled with the accurate distancedist
distance tables
tables that identify the premeasured ground distance between a select set of locations
route segments
put on maps to make up for functional time, and they give the travel time between distances
travel-time maps
show with straight lines and how much time it takes to get between locations
isochrones
lines of equal travel distance time
thinking geocentrically
thinking in terms of geographical direction
true north
a geographical fixed location, the north pole of the axis of the earth's rotation
true north reference line
any meridian that originates from the true north
Where is the north star
on the handle of the little dipper
grid north
the northerly or zero direction indicated on the datum of the map

it does not refer to a geographical place, it is artificial
grid declination
the angular difference between true north and grid north
magnetic north
the direction that your compass needle points to at the earth's magnetic pole
magnetic declination
the angular difference between true and magnetic north
isogonic lines
lines of constant angular distance between true and magnetic north
agonic line
where magnetic north and true north line up
Compass direction systems
compass points
azimuths
bearings
compass points
points indicated by arrows on the graphical face of a compass
azimuth
horizontal angle measured in degrees clockwise from a north reference line to a direction line
bearings
measured in degrees but only 0 to 90

measured either clockwise or cclockwise

give reference line (NS) and orientation (EW)
divisions in land partitioning
parcel
tract
lot
plat
maps drawn to scale to show lots in which the area has been subdivided
metes and bounds
a way of partitioning land based upon geographic features such as rivers, etc
seigneuries
parcels of land given to the elite and soliders in the french feudal system
french long lots
strips of land claimed along river banks. the strips were created by the owners of seigneuries, who then let everday people settle on them
land grants
parcels of land given to an owner before the land was given to the US
pueblo grants
issued to native american communities primaryily indian reservations in new mexico
private grants
property by the governments that could be sold by the owner and were made to individuals as a rewards for service to the government
community grants
land parcels that were given to groups of settlers
donation land claim
a 160 acre pacel that was given to settlers if they were on public land betfore the 1851 OR Wa ID treaty
centuriation system
a system of land partitioning first developed in roman times where land was divided into a grid and given away in parcels
what is the foundation of the US Public Land Survey System
the centuriation system of using grids
initial points and PLSS
the initial point to determine the parallel and meridian to base partitioning off of

the parallel is called the geographer's lie

the meridian is called the principal meridian
range lines
6 mile interval e-w marks from the initial point
township lines
6 mile intervals n-s marks
township
area bounds by 6 mi range and township lines
rows and columns on PLSS system
rows townships
columns ranges
indicating location in PLSS system
T#(NorS), R#(EorW)
sections
townships divided into parcels of 640. a seciton is one unit
correction lines
established every 4th township to correct because meridians converge towards the north pole
government lot
designed when a parcel hits a body of water
platted lots
parcels in a platted subdivision within a section
dominion land survey
public land survey system to divide canada's prairie land and western provinces
what is different about the dominion land survey in comparision to plss
the numbering order in a section is different

range lines ID with roman numerals
township lines only numbered
land records
public records of who owns land
Slope error increases with
increasing map distance and increasing slope
orient
to align a map with the directions on the ground
inspection method
a technique of orienting maps where you do not need to know where north is

orient according to the objects that are around you, such a as road
compass method
orienting by finding magnetic north

align the compass needle on the map and on the magnetic north of the actual compass
the difference between true north and magnetic north
20 degrees
distance estimation by the inspection method
find specific features on the ground, locate them on the map. estimate your ground distance and then find your map distance
why can it be hard to judge distance
because of the ocular vanishing point: the point on the horizon where parallel lines appear to converge
compass method of distance estimation
find the angle to your object, locate the back azimuth and draw a line on the map
resection method
using 3 objects to triangulate your position
what is crucial with the resection method
keeping you and the object in your line of sight as close to 90 degrees as possible
stadia principles
a way of measuring distance using equipment that is based on using a constant angle to determine distance between a marker and a sighting device
laser rangefinder
using infrared to measure distances up to 1,000 yds
altimeter
measures the height above a fixed level
intersection method
taking angles from multiple points towards an object and plotting those to find out your location.

opposite of resection
trilateration method
finding a location of a distant feature using only the distances from known locations of the feature

uses a drafting compass
navigation has how many parts
2

planning your route
following your route
Peutinger table
A Roman simplified map that was distorted to show the road network and cities along the routes
sounding
depth measurement
isobath
bathymetric contours
dead reckoning
used in nautical navigation where you determine your position based on where you are now relative to your last accurate location
what is the standard for writing coordinates/direction in nautical
course heading first then the boat speed
piloting
following your route using landmarks and water depth to aid navigation
scale on world aeronautical charts and sectional aeronautical charts and terminal charts
1:1,000,000

1:500,000

1:250,000
absolute positions
a specific position defined by coordinates such as lat/long, utm, spc, etc
two components of gis data
feature - the spatail aspect

attribute - describes some characteristic of the feature
space trilateration
used in GPS, where distance is measured in multiple locations based upon velocity and time of the signals to get to the location it was received
What are the components of GPS
a space segment, such as a satellite

user segment is the receiver that is tuned to the frequency of the space segment

control segment is the set of ground montoring systems that keep track of the satellites and their health
where are GPS satellites positioned
medium earth orbit
posigrade orbit
moving with the direction of the earth's orbit
selective availability
intentionally degradating the accuracy of the gps signal so that it could not be used by hostile forces
the accuracy of a gps depends upon
field conditions

location
length of time
arrangements of satellites in the sky
satellites and a solar day
satellites will appear 4 min earlier than they did earlier in the day
normal triliteration
the method of determining relative position by the geometry of triangles
what is a large source of error in GPS
the clocks not being sychronized

your position can be different because the two ranges of the gps will intersect at a different time than if they were synchronized
elevation determiniation and gps
gps are based off of the wgsd84 ellipsoid, which is a mathamatical model of the earth's surface.

the gps heights are based on ellipsoid approximations rather than real life
three sources of gps bias
the satallites
the gps signal
the receiver
range noise
random error in gps
observation noise
white noise of other ionospheric influences
error budget
describes the contribution of each sourceof error to the overall eroor of the satellite range of measurement
ionospheric effects
what layer of the atmosphere that the satellite is in can alter the speed and direction of a signal
receiver clock effects
the clocks inside of gps receivers are not as effective as atomic clocks
ephemeris bias
error in the position of the satellite due to the earth's gravitational pull
multipath error
when the path of the gps bounces before it makes it to the receiver
agonic line
the line of zergo magnetic declination along whihc the true and magnetic north poles are aligned
if NS utm grid lines tilt to the east...
the mapped region lies east of the central meridian of the utm zone
if the magnetic north line tilts east
mapped region is west of the agonic line
to get the back of an azimuth or bearing what should one do?
go backwards 180 degrees
explain how bearings are reported
in 0 to 90 degree increments eeither W or E of North, or W or E of South