GIS 1 exam 3
What are the steps in the geocoding process?
1. reference database 2. "address locator" style 3. address "parsing" and "grammar" 4. address matching 5. plotting
How does Dijkstra's algorithm work?
Assigns a cost to each edge for traveling across it
what is the traveling salesperson problem (TSP), what is it an example of, and how can it be solved?
TSP is a mathematical process involving determining the optimal configuration of rearranging a series of stops on a network. will examine the different combinations of how to reorder the stops to find the best route
how are addresses matched to a geospatial location through geocoding?
The geocoding process will set up multiple representations of the parsed address to cover the conditions. segments are searched according to the address locator style and attributes are used to find the best options for the segment to match the address
What is spatial autocorrelation? How does it help in pattern / cluster analysis?
a measure of the degree of clustering of objects and their data values. it helps by examining distributions of features and values
what is linear interpolation? how is it used to get a better spatial location match in geocoding?
a method used in geocoding to place an address location among a range of addresses. finds the correct location along the segment that the point will fit according to the attributes of the segment
what is the end result of a geocoding operation?
a new set of points representing the matched locations of each address found using this kind of reference data.
what is a service area? How is a service area different from a simple buffer?
a polygon boundary created around sections of a network to determine which areas of the network are within a certain distance of a location. constrained by the properties of the network rather than just a large circle like a buffer
how does the closest facility operation work in GIS? what is the end result?
a process used to determine which locations on a network are nearest (via network distances) to a different set of locations which libraries are closest to which high schools along the network
What is a line segment and how is a network modeled using line segments?
a single part of a line that corresponds to one portion of a street
What is hot spot analysis? What is the result of hot spot analysis in GIS?
a technique that determines spatial clusters of high and low values shaded areas to indicate high (red) and low (blue) spikes
what is impedance (transit cost)?
a value that represents hoe many units are used in moving across a network edge. (aka transit cost)
What does the Buffer operation do, and what is its purpose?
a zone of spatial proximity around a feature or set of features
How are the results of Moran's I interpreted?
allow you to examine the spatial auto correlation of the locations and their values
what is a spatial join?
appending attributes from one layer to another based on the spatial relationship of the layers
how are rankings used with address matching?
arcGIS Pro assigns a ranking of 0-100 to each potential candidate segment. higher numbers >80 are best candidates to choose for matching
what is address parsing and how is it used in the geocoding process?
breaking an address into its component parts separates street number, prefix, and name into individual items
What does the Append operation do, and what is its purpose?
combines 1 or more layers of data together with an already existing layer
What does the Merge operation do, and what is its purpose?
combines 2 or more layers of data together into a single layer
What does the Dissolve operation do, and what is its purpose?
combines polygons with similar attributes together
what is meant by "connectivity" in a GIS network and how and why does proper connectivity need to be set up?
connectivity is the linkages between edges and junctions of a network. without something to tell GIS that roads and railroads do not connect, it would fit them all together.
how do these two methods find a shortest route between stops?
costs are assigned to each node for traveling across it with the starting point being 0. costs are added up to find the smallest total to give the shortest route
how does the find service area operation work in GIS? What is the end result of it?
create a service area around a specific point on the network to see which areas are covered what are the serivce areas for libraries in the area (5280 ft = 1 mi)
what is the purpose of Dijkstra"s Algorithm?
determine the shortest path along a network from an origin node to the other nodes ont he network
what is spatial analysis?
examining the characteristics/features of spatial data, or how features spatially relate
What is a TIGER / Line file? Who makes them?
file produced by the US Census Bureau that contains the line segments that correspond with roads in the US
When can a spatial join be used instead of a regular join performed on two attribute tables?
find the closest feature to another what is within a frame what intersects a feature
what is the difference between finding the shortest route between stops in order and rearranging the stops concepts in GIS?
finding the shortest route with a specific order will give you the shortest distance you can travel from that limit order. the shortest distance rearranging the stops will give a lower value because the stops can be put into an order that works better to travel.
How does each of the following eight geoprocessing tools for polygon overlay function? Identity, Intersect, Union, Symmetrical Difference, Clip, Erase, and Update
identity - retains all the features from the 1st layer along with the features it has in common from the 2nd layer. shows land parcels and flood plains covering land parcels intersect - retains the features that are common to both layers. shows only land parcels that are also flood plains union - retains all the features from both layers. shows all land parcels and all flood plains symmetrical difference - retains all features from both layers except the ones in common. show all land parcels that are not also in flood plains. shows flood plains that are not also on land parcels clip- extracts objects from 1 layer based on the geometry of the 2nd layer. clip roads based on county boarders erase- retains features from 1st layer except for what they have in common with 2nd layer. show all land parcels except those on flood plains update - retains all features from the 2nd layer as well as those from the 1st that are not in common with the 2nd
what is a turn? how are turns handled on a network?
information used by arcGIS Pro to determine information about valid flows along a network
What is the basic structure of a network in GIS (i.e. what are edges and junctions)?
junctions (nodes) and edges (lines) connected together
what are some real-world applications of the shortest path concepts?
mail delivery routes, fedex delivery schedules
What is batch geocoding?
matching a group of addresses together at once
what are some reasons an address would be geocoded to an incorrect location?
misspelling, incorrect values, missing information, outdated reference database, address out of range
why would linear interpolation cause an address to be matched to an incorrect location?
outdated reference database, reference database doesnt recognize address, address is out of range
How do buffers operate for the three vector objects (points, lines, and polygons)?
point - circular buffer surrounding the point line - width extended around the line polygon - addition of exterior area to the polygon
how does select by location operate? what is selected by a selection by location operation?
pro tool used to select features from one or more layers based on their spatial relationship to another layer
What is the purpose of Line-on-Polygon Overlay, how is it performed, and what would be the specific output of it?
results in a new line layer where the lines have the attributes of the polygons within which they are. lines on polygons results = new line layer ! line can have 3 attributes if in 3 different polygons
What is the purpose of Point-in-Polygon Overlay, how is it performed, and what would be the specific output of it?
results in a new point layer where the points have the attributes of the polygos within which they are. points onto polygon end result = new point layer wells on a land parcel
What are some real-world applications of overlay operations (and how are they used)?
roads on soil layers wells on soil flood plains and land parcels roads in counties
What is Python and how is it used with ArcGIS Pro?
scripting and programming language used for automatic tasking
what are some applications of selection by location?
select counties that contain state capitals or counties within 50 miles of youngstown
what is a spatial query? how does it differ from a regular select by attributes query?
selecting records/objects from a layer based on their spatial relationships with other layers rather than their attributes
What is Moran's I?
spatial auto correlation tool in analyzing patterns toolbox
What is an Address Locator and how is it used in the geocoding process?
specifies the reference data, geocoding style, and necessary attributes for geocoding. establishes parameters for how geocoding will be performed
When overlaying two polygons, what is the output of an operation in terms of the new object created and how is this new object's attribute table affected?
the 2 layers are combined to create a new 3rd layer with a combined attributes table
What is an overlay operation?
the combining of 2 or more layers together in GIS
in select by location operation, what does the target and source layer do?
the target layer is input layer the source layer is the location or area (spatial) you want your data to be in
What key attributes are included in a TIGER / Line file? How are these attributes used in the geocoding process?
they are street centerline files used in GIS to model each street as a series of line segments
How is GIS used in examining patterns and clusters of geospatial data?
using spatial statistical tools --> spatial autocorrelation or analyze patterns
What is geoprocessing?
when an action is taken to a dataset that results in a new dataset being created
What is geocoding and how is it used?
process of using the numbers and letters of an address to plot a point at that location
What are examples of different types of Address Locator Styles?
dual ranges
