GIS Final Exam Flashcards
What does LIDAR stand for?
Light Detection and Ranging
What are the common uses of GIS?
Navigation, land use/ownership/municipal, land formations/terrain models, environmental monitoring/modeling
What file type is the main working space in GIS?
.MXD (Map Document)
T/F No GIS data is stored in the .MXD file
True - just map elements and graphics, and references other data. This is used to conserve space.
Which file stores most of the GIS data?
.GDB (Geodatabase)
T/F .GDB (Geodatabase) is a version of Microsoft Access Database
True
T/F .GDC (Geodatabase) is multiple files
False - it is one file, but holds multiple layers, tables, photos, relationships, etc.
T/F Shapefiles comes in multiple file types
True
What does .shp (Shapefile) include?
The feature geometry itself
What does .shx (Shapefile) include?
Positional index of the feature geometry
What does .dbf (Shapefile) include?
Attributes for each shape
What Shapefile type contains the geospatial metadata in XML format?
.shp.xml
What does .prj (Shapefile) contain?
Coordinate system and projection information
What is a .mpk file?
Map package - files that enables you to zip up all the files into one
What is the .lyr file?
Layer file - it contains a link or pointer to the location of the data and contains info on how to render or draw the data
What is the Google Earth file type?
.kmz and .kml
What are the raster data file formats?
.jpg/.jpeg/.tiff/.png/.img/.grid/.asc/.sid
What do raster data formats include?
Aerial photos, digital elevation models, geo
What type of file is for data collected with lasers?
.las or .laz
What do .las (Lasers) contain?
Set of points with x, y, and z coordinates. Sometimes also RGB values for classification, intensity, and color
What does .lasd file do?
A translator file that allows ArcGIS to read, display, transform, and analyze the .las files
What land use color is used for industrial?
Light grey to dark grey (light to heavy industrial)
What are blue land use types?
Institutional (public buildings, schools, hospitals, churches)
What land use color is used for special types (i.e. tourism, historic, utilities, etc.)
Purple
What does green land use (greenspace) include?
Agriculture, open space, parks
What land use color is used for low and medium density residential?
Yellow to orange
What land use color is used for high density residential?
Brown
What is the red land use color?
Commercial (office and retail)
What are the 7 classification options in “Quantities” in Symbology?
Manual, Equal Interval, Defined Interval, Quantile, Natural Breaks, Geometric Interval, Standard Deviation
T/F The classification method will not have much significant change in cartographic display
False
What needs to be taken into consideration when deciding which classification method to use?
The audience/consumer of the map
What is Equal Interval classification?
Divides the range of attribute values into equal-sized ranges.
How many classes can you have in Equal Interval?
As many as you want.
Give an example of Equal Interval classification
You choose how many classes you want 0 - 20 21 - 40 41 - 60 61 - 80 81 - 100 101 - 120
Which classification involves specifying an interval size to define a series of classes within the same value range?
Defined Interval
What is the Quantile classification?
Each class contains an equal number of features
Which classification involves breaking classes on groups inherent in the data?
Natural Breaks
T/F You always use Natural Breaks classification for socio-economic factors
False - classes are not uniform
How does Natural Breaks create classes?
Class breaks are identified that best group similar values and maximize the differences between classes.
Which classification was designed specifically to accommodate continuous data?
Geometric Intervals
Natural Breaks are the compromise method between which three classifications?
Equal Interval, Natural Breaks, and Quantile
What are Natural Breaks measured in?
Jenks
T/F Geometric Interval is used for socio-economic factors
False
Which classification works best with continuous data, such as rainfall?
Geometric Interval
Which classification is not good for mapping?
Standard Deviation
What is the Standard Deviation classification method?
Shows how much a feature’s attribute deviates from the mean
What does ArcMap calculate?
Mean and standard deviation
What are class breaks?
Created with equal value ranges that a proportion of the standard deviation`
What intervals are class breaks in?
intervals of 1, 1/2, 1/3, or 1/4 standard deviations using mean values and standard deviations from the mean
NRDSC CT BG CB
Nation, regions, divisions, states, counties, census tracts, block groups, census blocks
What does CDP stand for?
Census Designated Places
What are Census Designated Places?
Delineated to provide data for settled concentrations of population that are identifiable by name but are not legally incorporated under the laws of the states
What are the four projections?
Conic, cylindrical, plane, interrupted projection
What is a datum?
Plane, straight line, or point used as a reference when processing a material of measuring the dimensions of a target
What is a mercator?
Meridians appear at right-angles to the equator, and lines of latitudes are horizontal lines who distance from each other increases with distance from the equator
What is the transverse mercator?
Similar to Mercator except the cylinder touches the sphere or ellipsoid along a meridian instead of equator
T/F The central meridian selected by the mapmaker touches cylinder if the cylinder is tangent in a transverse mercator.
True
T/F The transverse mercator cannot show the whole Earth
False
T/F The directions, distances, and areas are reasonable accurate only within 25 degrees of the central meridian in transverse mercator.
False - 15 degrees
T/F There are no straight rhumb lines in a transverse mercator.
True
Define the Albers Equal Area Conic
Two standard parallels and equal areas.
T/F Deformation of shapes increases toward standard parallels.
False - AWAY from standard parallels
How many UTM and state plane zones are there in the United States in the Lambert’s Conformal Conic Projection?
20
What is the most common projection for GIS of Florida?
State Plane Florida West, East, North
What is the PLSS?
Public Land Survey System
The PLSS typically divides land into what?
6-mile-square townships
What are townships divided into?
36 one-mile-square sections
What can sections be divided into?
Quarter sections, quarter-quarter sections, or irregular government lots
T/F A permanent monument (marker) is placed at each section corner
True
T/F Monuments are only placed at section corners
False - monuments can also be placed at quarter-section corners and corners of government lots
What is range?
A vertical column of townships in the PLSS. West and East.
What is a section?
One-square mile block of land
How many acres in a section?
640 acres (1/36 of a township)
T/F Sections are never smaller than one-square mile
False - due to the curvature of the Earth, sections may be slightly smaller than one-square mile
What are the two lines for the PLSS?
Principal Meridian and Base Line
T/F - The rows of numbers along or parallel to the principal Meridian (North and South) are called Numbers of Ranges
False - Numbers of Townships
What are the rows of numbers running parallel to or along the Base Line (East and West) called?
Number of Ranges
T/F The principal Meridian runs East and West
False - North and South
What does COGO do in ArcGIS?
Coordinate geometry
What is COGO used for?
Coordinate geometry descriptions are used to re-create the features that a surveyor captured.
What do you georeference raster data?
This turns it into georeferenced raster data, which involves defining its location using map coordinates and assigning the coordinate system of the map frame so you can view, query, and analyze with other geographic data.
What is Metadata?
File of information (usually XML) that has the basic characteristics of data or information resource
What type of data is documented in geospatial metadata?
Geographic digitial data (GIS files), geospatial databases, earth imagery, data catalogs, mapping applications, data models, websites
What are the four main types of projections?
conic, cylindrical, plane, interrupted
The UTM and State Plane Zones are in which projection?
Lambert’s Conformal Conic Projection
What is the UTM?
Universal Transverse Mercator (coordinate system)
How is the UTM divided?
Sixty north-south zones, each 6 degrees of longitude wide
What datum does every state plane system use?
NAD83 (North American Datum)
What is the WGS 84 coordinate system?
World Geodetic System
What is WGS 84 coordinate system used for?
GPS
What file of a shapefile holds the geographic info of the state plane coordinate system?
.prj
What does a .prj file hold?
coordinate system and projection information
What is the Standard Hierarchy of Census Geographic Entities
NRDSC CT BG CB
Nation, regions, divisions, states, counties, census tracts, block groups, census blocks
What are the AIANNH Areas?
American Indian, Alaska Native, Native Hawaiian Areas
What is the NRDSC CT BG CB?
Standard Hierarchy of Census Geographic Entities
How many files does a shapefile have?
3 to 7, depending on how it is generated (projection, etc.)
What does the xml files contain?
Metadata
What are the possible extensions of a raster file?
.jpg, .png, .img, .tiff, .jpg2, .grd, .asd, .sid
What would I use to select zip codes in Hillsborough County?
Select by Location, because zip codes do not come with counties attached to them
How to connect spatial joins and selections?
The polygons are not drawn perfectly, so you use the centroid
Why would you summarize?
Summarize data into a table, you can get summary statistics (count, average, minimum, and maximum values)
Why join this table to attribute table of a layer?
Symbolize, label, or query the layer’s features based on their values for the summary statistics
T/F You always highlight the layer that you are joining to
True
If you are doing spatial selection for a target feature layer and they are points, what selection method do you use?
Intersect the source layer feature
What is collective Lidar data referred to as?
Point Clouds
What are the three types of Lidar sensors and applications?
Aerial Lidar, Mobile Lidar, Terrestrial Lidar
What is Aerial Lidar data used for?
Map elevations of the earth’s surface
What are the four digital models created using aerial Lidar?
Digital Elevation Model (DEM)
Digital Surface Models (DSM)
Digital Height Above Ground Models (HAGL)
Digital Hillshade Models
Where are Mobile Lidar sensors attached to?
automobiles, trains, and other vehicles
T/F Mobile Lidar data collects data as a vehicle travels
True
Name some examples of Mobile Lidar data applications
transportation monitoring, utilities mapping and monitoring, high resolution site modeling, self-driving vehicles
How is Terrestrial Lidar data collected?
From a tripod
T/F Terrestrial Lidar has the lowest resolution Point Clouds
False - highest resolution Point Clouds
T/F RGB values can be collected along with the XYZ point cloud measurements with Terrestrial Lidar
True
Examples of applications that use Terrestrial Lidar Point Clouds?
Site modeling, architecture, construction, engineering, virtual reality, CGI, etc.
What is the advantage of Aerial Lidar technology compared to remotely sensed elevation data?
Able to capture all the features on the ground and produce images with resolution of 1x1 foot pixels
T/F Radar technology is limited to just ground data
True
What is the best resolutions of radar technology?
30x30 foot pixels
How many pulses of light per second with Aerial/airbourne Lidar?
400,000 pulses of light per second
How are elevation levels calculated from Aerial Lidar?
Laser transmits pulses and records the time delay between a light pulse transmission and reception.
How are Point Cloud data produced?
Elevation values are integrated with info from aircraft’s GPS and orientation data from inertial measurement technology
What kind of data does orientation/Aerial Lidar include?
Pitch, roll, yaw
Why is Aerial Lidar unique?
Laser pulses that are shot down to the ground can be split.
T/F When a pulse is split, only one measurement is returned.
False - multiple measurements are returned
T/F A Lidar can send out 1,000,000 pulses, but records 1,050,000 measurements
True - pulses return multiple measurements
What is a major advantage of multiple returns?
Vegetation penetration
T/F The pulse from Aerial Lidar can make it through holes in the tree canopy and hit multiple features like branches throughout the tree and still hit the ground
True
What is the Multiple Return Explanation?
Lidar pulse sends out, 1st return, then 2nd return, then 3rd return, then 4th return, before hitting the ground at 5th return
T/F The 1st return is the least significant with Aerial Lidar
False - 1st returned laser pulse is the most significant return, includes highest feature in the landscape like a treetop or the top of a building
T/F Lidar produces x, y, z measurements
True
What is the INS on Lidar?
Inertial navigation system
What does INS (inertial navigation system) measure on Lidar?
roll, pitch, heading
T/F One emitted pulse can return only one return (Lidar)
False - many returns
T/F The last return from Aerial Lidar is always a ground return
False - If a thick branch is on ground floor, that might be the last return instead of bare earth
What is a return with Aerial Lidar?
When the pulse comes back
What is included in Aerial Lidar Point Cloud?
Elevation measurements, feature classification, return number
What instrument collects Aerial Lidar Point Cloud?
airplane or drone
What are used to create Digital Models from Aerial Lidar Point Clouds?
Elevation measurements, feature classification, return number
What is a LAS Dataset Statistic?
Statistics of return and classification information of all LAS files within the .lasd
What does LAS include?
Set of points, x y z coordinates, RGB values for classification, intensity, and color
What is Raster Interpolation (.las)?
Predicts values for cells in a raster from a limited set of sample data points
T/F Interpolation (.las) can be used to predict known values for any geographic point data (elevation, rainfall, chemical concentrations, etc.)
False - predicts UNKNOWN values
T/F A temperature map of the U.S. is considered an Interpolated Map
True
What are the three models generated from Aerial Lidar?
Digital Elevation Model (DEM)
Digital Surface Models (DSM)
Height about Ground Level (HAGL)
What is the difference between DEM and DSM?
Digital Surface Models (DSM) shows both ground elevation and also elevation of objects on the surface (i.e. Elevation of Roof above sea level) which includes ground elevation + elevation of object
What does the Height Above Ground Level Model show?
Not from sea level, but only shows elevation from ground level (i.e. Height of Roof is 20 feet above ground level). Ground Height = 0
How are DEMs and DSMs calculated?
Interpolating classified ground points
How is HAGL calculated?
Subtracting the DEM from the DSM (DSM - DEM)
What tool is used for HAGL to subtract the DEM from the DSM?
Map Algebra tool -> Raster Calculator
How are Digital Hillshade Models generated?
Degree of slope for each Pixel/Raster Cell
How do traditional Greyscale/Shaded Relief Models created?
Use shading effect from Azimuth and Altitude of the Sun
T/F Less detailed Grayscale/Shaded Relief Models use a multi-directional Hillshade
False - More detailed
T/F Natural Breaks should be used for socio-economic factors
False - DO NOT USE for socioeconomic factors
What are Natural Breaks not a good classification for socio-economic factors?
The classes are not uniform
T/F Equal Interval is best used for data ranges like percentages and temperature.
True
What are Lidar Point Clouds?
Large collections of 3D elevation points, which include x, y, and z, along with additional attributes such as GPS time stamps.
Which classification is used for visualizing data that is not distributed normally, or when the distribution is extremely skewed (i.e. rainfall)
Geometric interval
T/F Geometrical intervals classification is worse than quantiles for visualizing prediction surfaces, which often do not have a normal data distribution
False - Better
T/F Quantile classification does not have a normal data distribution
True
When does the Geometric Interval classification work best?
When the data is spread over a large area and is not well distributed.
