3426final Flashcards
identifying relevant factors and adding their appropriately weighted values
cartographic modeling criteria
can be expressed as a script, or visually as a flowchart
modeling data
.
modeling techniques
4 major steps in GIS project
- Determine objectives & design the model/design the database
- build the database
- Perform the analysis
- Present the results
types of models
descriptive, predictive, prescriptive.
“airline” distance, Eclidean or City Block
straight line distance
city block measure, aka
manhattan distance
sum of the lines that make up a certain pathway
route distance
used to determine straight line distance
pythagorean theorem
How curvy a line is, Length of Line A (the straight line from end to end) divided by the length of line B (the actual line)
sinuosity
the measurement of the perimeter of th epolygon
polygon circumference
a hole with vertices in a polygon
euler holes
the curvature of a raster surface
convexity
least cost path, a distance measurement that take impedance into account
functional distance
absolute and relative, cause some kind of friction on the path
impedance/barriers
a raster surface that clculates the cost of pathways
cost surface
shortedt path, functional distance
least cost path
examples of classification systems
.
classification vs. reclassification
The process of sorting or arranging entities into groups or categories; on a map, the process of representing members of a group by the same symbol, usually defined in a legend.
he process of taking input cell values and replacing them with new output cell values. Reclassification is often used to simplify or change the interpretation of raster data by changing a single value to a new value, or grouping ranges of values into single values
he process of taking input cell values and replacing them with new output cell values. Reclassification is often used to simplify or change the interpretation of raster data by changing a single value to a new value, or grouping ranges of values into single values
reclassification
A data classification method that distributes a set of values into 4 groups
quartile reclassification
A data classification method that distributes a set of values into groups that contain an equal number of values
quantile reclassification
A method of manual data classification that seeks to partition data into classes based on natural groups in the data distribution. Natural breaks occur in the histogram at the low points of valleys. Breaks are assigned in the order of the size of the valleys, with the largest valley being assigned the first natural break.
natural breaks
A data classification method that divides a set of attribute values into groups that contain an equal range of values.
equal interval
using the reclass tool to manually input new values for certain ranges of values in a raster
manual reclassification
makes shared polygon boundaries disappear
dissolve
line, polygon, point, exterior polygon, interior polygon, variable,
types of buffers
a set of research methods developed in computer science to enable the controlled manipulation of data represented graphically to enhance readability, or to reveal or demonstrate unsuspected patters, regularities, or connections
visualization
.
multi-dimensional
user interaction and query across place and time, maps linked to other data visualization
dynamic and linked maps
teamwork among place-based subjects that is facilitated with and through geographic information and technologies, a field of study that is multidisciplinary in
nature, incorporating theory and methods from human-computer interaction (HCI), computer science, and
psychology
geocollaboration
surface representations: raster
tesselation
lattice
vector surface representation
TIN
vector surface representation
these are used in a TIN to represent slope, aspect, area
nodes, edges, triangles
artificially altering elevation, useful for regions of little variation, useful for features
vertical exaggeration
visually overlaying data on elevation surface
draping
.
resistance
.
barriers
a collection of data
database
software/programs that control the database
database management system
advantages of DBMS
reduces redundancy, maintenance cost decreases, multiple apps can use the same data and evolve, yser knowledge can transferred, data sharing is facilitated, security standards can be inforced, able to manage large numbers of concurrent users
records, rows, in a table
tuples
relations
tables
tables
relations
tuples
records
fields, columns, in the table
domains
domains
fields
one or more fields that uniquely identify each record
primary key
field in a table that matches the primary key field of another table
foreign key
a family of algebra with a well-founded semantics used for modelling the data stored in relational databases, and defining queries on it
relational algebra
four basic commands
select, insert, update, delete
SQL
.4 basic commands of SQL
select, insert, update, delete
1st step in a GIS project
needs analysis
the ability to tell a story with maps, problem solve, demonstrate technical expertise in applications, use social skills
GIS talent
recognize spatial pattern and/or process and contributing factors
analytical model design
this involves visualizing patterns, categorizing, and discovering
recognize spatial pattern/process
this invloves looking at causes, independent and dependent variables, and cartographic modeling
contributing factors
To do this, you must look at scale, resolution, level of detail, classification, projection and coordinate system, software, study area
database design
looks at application and education opportunities
pilot study/ feasability study
Primary data sources are those collected in digital format specifically for use in a GIS project.
Secondary sources are digital and analog datasets that were originally captured for another purpose and need to be converted into a suitable digital format for use in a GIS project
data definition and collection
technical design (can we do it technically?) Institutional design (do they want us to do it?)
system design
system design question: can we do it technically?
technical design
system design question: do they want us to do it?
institutional design
.
GIS customization/programming
static map delivery, minimal user interaction, interctive mapping and query
Internet delivery
ex: census maps
Static
ex: campus map
minimal user interaction
ex: story maps
interactive
model that illustrates existing conditions, isolates specific factors to clarify what is going on
descriptive model
model that asserts a causal relationship
predictive
model that employs a known causal relationship to engineer a desired result in a specific instance
prescriptive
a perspective of a model, ex streamflow modeling
objective
a perspective of model, ex preserving farmland while allowing urban growth
subjective
The first step in model formulation is
designing a project
start with intended output, maximize flexibility, stepwise refinement
the second step in model formulation is
model verification
does your final map show what you think it is
which operations, and in what order, must be though-out:
in advance
in multifaceted analysis, the process is not linear, it is
iterative
this aids the modeling process by diminishing the complexity of the task, permitting planning in an organized manner, providing documentation
flowcharting
using pythagorean theorem, counting cells in a grid representation
euclidean distance
how many other cities within a certain distance of each city
point neighborhood operations
the first step in calculating a least cost path in raster is
to choose a starting point and search nearest neighbors for easiest route
how many connections can be made from each cell
8
what is the sum of accumulated cost surfaces
least cost surface
a network is a higher order
linear object
interconnected lines that allow movement or flow
network
a network has a ____ data structure, including
topologic, junctions (nodes) and edges (arcs)
connectivity, turns, elevation, direction are all
network charcateristics
three major types of networks
straight-line, branching, circuit
flow is subject to
resistance
resistance determines the
direction and speed of flow
a network that restricts the flow to a single direction
directed network
a network that allows flow in both directions
undirected network
network delivery or pick up points
stops
network allocation or catchment areas
centers
used for direction and flow analysis
turns
tree building algorithm
minimize cumulative cost path
path finding variations
shortest path, quickest path,vehicle routing, closest facility, service areas
what are some advantages to a TIN
good for representing elevation data, good for representing data with both very large and very small areas of homogeneity, can look at either the facets or the edges between them
what are some disadvantages to a TIN
complex, no overlay
costs considered in a cost benefit analysis
hardware, software, personnel, data collection, maintenance
benefits in a cost benefit analysis
direct, agency productivity, government, external
an integrated set of data on a particular subject
database
a software application designed to organize the efficient and effective storage and access of data
DBMS
what are the three main types of DBMS
relational, object, object-relational
a database comprised of a set of tables, each a two dimensional list or records containing attributes about the objects under study
relational database
a database initially designed to address weaknesses of the relational database, including the inability to store complete objects directly in the database
object database
a database that can handle both the data describing what an object is and the behavior that determines what an object does
object-relational database
relational databases are made up of
tables
how many methods are there for testing spatial relationships between geometric object
9
what are the nine methods for testing spatial relationships?
equals, disjoint, intersects, touches, crosses, within, contains, overlaps, relate
this returns a geometry that represents all the points whose distance from the geometry is less than or equal to a user defined distance
buffer
database design involves three key stages:
conceptual, logical, physical
the conceptual model involves
model the user’s view, define objects and their relationships, select geographic representation
the logical model invloves
match to geographic database types, organize geo database structure
the physical mode involves
defining the database schema
what are the two main structuring techniques relevant to geographic databases
topology creation and indexing
this is a special representation of information about objects that improves searching
database index
what are some types of indexes
grid index, quadtree index, R-tree index,
formal descriptions of datasets that satisfy many different requirements
object-level metadata
combines information from the database with information from the senses
augmented reality
entails multiple representations of large and complex datasets, on the fly
geovisualization
allowas users to explore, synthesize, present, and analyze their data more thoroughly than was possible hitherto
geovisualization
map transformations that distort area or distance in the interests of some specific objective
cartograms
uses the intersection of two datasets to obtain more precise estimates of spatial distribution
dasymetric
the two dimensional equivalent of the mean
centers
the most convenient way of summarizing the locations of a set of points
the centroid
the path through the network between a defined origin and destination that minimizes distance, or some other measure based on distance, such as travel time
the shortest path
choosing a GIS involves four steps:
analysis of requirements, specification of requirements, evaluation of alternatives, implementation of system
T/F autocorrelation occurs when two phenomena have similar spatial patterns
false
a map projection that maintains correct directions is called
azimuthal
estimating a point value outside the geographic range of points of known values leads to
edge effects
