gis coordinate systems

Question 1

coordinate pair

Answer 1

x-y value undicating a position a planar coordinate sytem

Question 2

coordinate space

Answer 2

range of x and y values onto which maps are plotted

Question 3

origin

Answer 3

origin of a coordinate system

Question 4

map units

Answer 4

units of coordinate system in which a map is stored or displayed

Question 5

coordinate system

Answer 5

specified range of x-y values onto which a map is plotted or the definition of a coordinate space used by a map layer, including the ellipsoid , datum , and projection

Question 6

degrees

Answer 6

measurement units used in the spherical coordinate system: a circle has 360 degrees

Question 7

longitude

Answer 7

a spherical unit measuring angular distance east or west from the prime meeridian

Question 8

prime meridian

Answer 8

the line of zero longitude on the earth, passing through Greenwich, England

Question 9

lattitude

Answer 9

a spherical unit measuring angular distance north north or south of the equator

Question 10

GCS

Answer 10

sperical coordinate system of degrees of lattitude and longitude that is used to locate features on earth’s surface

Question 11

spheroid

Answer 11

kind of ellipsoid

Question 12

ellipsoid

Answer 12

spheroidal volume with unequal axes, used to approximate the shape of the earth in map projections

Question 13

geoid

Answer 13

shape of earth as defined by mean sea level and affected by topographic and gravitational factors

Question 14

datum

Answer 14

combination of an earth ellipsoid and a reference point to reduce mapping discrepancies for a particular region

Question 15

transformation

Answer 15

conversion of one geographic coordinate system and datum to another

Question 16

cylindrical projection

Answer 16

a map projection derived by projecting sperical latitude-longitude values onto a cylinder wrapped about a sphere

Question 17

transverse projection

Answer 17

a map projection in which spherical coordinates are converted to locations on a cylinder or cone tangent to the sphere along a line of longitude

Question 18

oblique projection

Answer 18

a map projection in which projections on a sphere are projected to cylinder or cone of paper at an arbitrary angle

Question 19

conic projection

Answer 19

a map projection derived by projecting latitude-longitude values on a paper cone covering a sphere

Question 20

tangent projection

Answer 20

a map projection in which sperical coordinates are projected upon a surface that lies tangent to the spere along one line of latitude

Question 21

secant projection

Answer 21

a map projection in which spherical coordinates are projected onto a surface that intersects the sphere along two great circles

Question 22

azimuthal projection

Answer 22

a map projection onto a flat plane that is tangent or secant to the earth’s surface

Question 23

stereographic projection

Answer 23

a map projection in which locations on a sphere are projected onto a planar surface

Question 24

orthographic projection

Answer 24

a map projection in which locations on a sphere are projected onto a planar surface

Question 25

parameters

Answer 25

specific values associated with map projections that define how it appears; variables that serve as inputs to models

Question 26

central meridian

Answer 26

the central longitude of a map projection for which the the x coordinate equals zero

Question 27

lattitude of origin

Answer 27

a reference lattitude of a map projection where the y value is zero

Question 28

reference latitude

Answer 28

the lattutude of origin

Question 29

standard parallel

Answer 29

a parameter of a map projection indicating the lattitude(s) at which the projection surface lies tangent or secant to the sphere

Question 30

false northing

Answer 30

arbitrary y-coordinate translation applied to map projection, usially to ensure that all values are positive

Question 31

false easting

Answer 31

arbitrary x-coordinate translation applied to map projection, usially to ensure that all values are positive

Question 32

spatial referecne

Answer 32

the complete description of how the spatial data are stored for a feature class that includes the coordinate system, the X/Y Domain, and the precision

Question 33

georeferenced

Answer 33

a spatial data layer that is tied to a specific location on the earth's surface for display with other data

Question 34

world file

Answer 34

text file containing the georeferencing information for a raster

Question 35

ground control points

Answer 35

a set of points that match easily identifiable locations on two different data layers to enable georeferencing of one layer to another

Question 36

rectify

Answer 36

to rotate, resize, or warp an image to match a map base using a selected set of ground control points

Question 37

affine transformation

Answer 37

process to translate, rotate, or skew an image to fit a new coordinate system

Question 38

rubbersheeting

Answer 38

process to deform a raster to fit it to a new coordinate system

Question 39

RMSE

Answer 39

The root mean squared differences between a set of original and translated points

Question 40

UTM

Answer 40

family of map projections defined for 60 zones around the world and based on a transverse cylindrical projection

Question 41

State Plane

Answer 41

group of projections defined for different regions of the United States and designed to minimize map distortions

Question 42

X/Y domain

Answer 42

maximum allowable range of values stored by a feature class

Question 43

resolution

Answer 43

the ground area represented by one cell value in a raster; default storage precision of vector data set

Question 44

extent

Answer 44

the range of x-y coordinates displayed in a map or stored in a data layer

Question 45

Define Projection tool

Answer 45

tool to guide the user through the task of assigning a coordinate system to a spatial data layer

Question 46

Project tool

Answer 46

too that converts a feature class from one coordinate system to another

Question 47

projection

Answer 47

mathematical transformation that converts spherical units of lattitude and longitude to a planar x-y coordinate