GIS FINAL EXAM QUESTIONS AND ANSWERS
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What does GIS stand for? - answerGeographic information system
Given a good definition
... [Show More] for GIS, list the four components and put a star next to the most important one - answersoftware, hardware, spatial data, people*
List four things GIS can do - answerenter data, store/display data, analyze data, manipulate data
Name the two general types/kind of data - answerattribute and spatial
example of spatial data - answerspaulding hall, room 217, UNH, Durham NH
example of attribute data - answerthere are 30 cats in a veternarian clinic. 15 of the cats are black
spatial data - answergeometric, coordinates, location
attribute - answernon-spatial characteristics nominal (descriptive), ordinal (range), interval/ratio (order and distance)
uses lines, points(x,y) and polygons to make up spatial features on a map. The topology is CREATED using attribute tables and features. More complex but more visually pleasing - answerVector format data
topology - answerwhat is next to what and what is connected to what. the spatial relationship between cartographic features. defines adjacency and connectivity.
equal grid cells or pixels. larger cells show poorer spatial resolution. easier to manipulate but uses A LOT of storage space - answerraster format data
topology in raster - answertopology in raster data is IMPLICIT through the cartesian coordinate system. you know that (2,1) is connected to (2,2) because it is implied
what is the purpose of database structures - answerto manipulate, query, analyze, and organize tabular data
what is the main difference between network and hierarchal database structures - answernetwork database is more flexible due to having multiple parents and multiple children all connected.
however, it shares data and can be complex. hierarchal is harder to manipulate having a 1:1 parent children ratio, it is very defined.
what is a relational database - answerdata and information is formally structured through a set of connected tables. MOST COMMONLY USED IN GIS
what is the main purpose of a map projection - answerto take a 3D globe and put it on a 2D surface
what is the most commonly used database in GIS - answerrelational
which general class of map projections is used to project an entire hemisphere? why is this used - answerCONICAL--> it has fewer distortions
prime meridian - answer0 degrees longitude
equator - answer0 degrees latitude
cylindrical projection - answerwhole earth
puts cylinder over earth--touches only at edges
meridians mapped to equally spaced vertical lines and circles of latitude are mapped to equally spaced horizontal lines
conical projection - answerbest for entire hemisphere, fewer distortions
azimuthal projection - answerplanar, touches only at edge
projection distortions - answerconformal (cylindrical), equivalent (azimuthal), and perspective
what is the best way to obtain GIS layers - answerthe best way to get layers to do the analysis is to check for already created data from places like USGS, GRANIT, EPA, USDA. if the data is accurate it saves time and money.
what is the most important factor to consider when obtaining GIS data - answerhow ACCURATE the data is
why was there an immense amount of effort in developing raster compression/encoding methods
- answerbecause raster data is extremely complex and takes up a lot of space
encoding - answerraster compression
types of encoding (compression) - answerblock coding, chain coding, full length, quadtree
define the concept of scale - answerMD/GD scale is the ratio between map distance and ground distance. as the scale gets larger (1:12,000) it becomes more detailed for the objects are larger. as the scale get smaller (1:100,000), it becomes less detailed and the objects are larger
small scale - answerlarger numbers--objects are small--less detailed
large scale - answersmaller numbers--objects are large--more details
coordinate transformation - answerregistration
why is coordinate transformation so important - answerwhen you transform a 2D map layer onto another coordinate system, the layers need to line up
what are some specific sources of GIS data - answerUSGS, USDA, U.S. Forest Services, GRANIT, U.S. Park Services
physical imput of data, star next to what one you wouldnt use today - answerfull length encoding*, scanning, digitizing
what is a datum - answera standard used in GIS to make measurements
types of datums - answerNAD17, NAD83, USG84
if two layers have different datum info - answerthe layers will not line up--one must be switched
3 most common coordinate systems in the U.S. - answerLatitude/longitude, universal transverse mercator (UTM), and state plane
which coordinate system would be the worst for conducting a study in three different states - answerstate planar because each state has different coordinates that you would have to link together, instead of the other two which have the same system spanning all the states
map - answercartographic representation of geographic reality
GIGO - answergarbage in garbage out:
data quality/metadata, data about data importance
geogesy - answerscience of studying the shape of the earth
geoid - answerthe true representation of the earth's undulating shape taking into consideration the gravitational pulls and densities [Show Less]