ENVSOCTY 2GI3 FINAL - EXAM PRACTICE
QUESTIONS V2 (2ND HALF MATERIAL)
Describe the 3 systems of georeferencing and give an example of how each one could
be used. - Answer -1. Metric: the location is defined using measures of distance from
fixed places; metric is the foundation of all 3
Ex: a GPS defines location based on their distance from a fixed location
2. Nomial: locations are defined with placenames
Ex: Hamilton, St. Clair River, Canada
3. Ordinal: Locations are ordered in some manner
Ex: Postal addresses: an area is given the first 3 characters, then each smaller area
within that area is given 3 more character, defining the area
Which of the following would not be well represented by a raster model?
Soil Properties
Elevation
Population
Precipitation - Answer -population
Which of the following would not be well represented by a vector model?
Population
Elevation
Soil quality
Population density - Answer -elevation
At least 2 [ ] define a line segment; one or several line segments define a(n) [ ]. Angle
points are [ ] and endpoints of a(n) [ ] are [ ] - Answer -points, arc, vertices, arc, nodes
What is topology? - Answer -the math of how features join
True or false: points, lines, and polygons cannot exist within the same vector layer -
Answer -True; they must each have their own layer
Describe the spaghetti data model - Answer -It lists coordinates, with lots of duplication;
there are no relative relationships encoded; it is just the point/line/polygon, and the
coordinates associated with it
Describe a node file in a topological data model - Answer -it is similar to a spaghetti
model in the fact that it lists the points and their associated coordinates
, Describe an arc file in a topological data model - Answer -It lists each arc #, the start
(F) node and the end (T) node, the vertices present (if any), and the polygon to the left
and right of it
Describe a polygon file in the topological data model - Answer -It lists the polygon #
and the arcs that make it up; if there is a 0, that means the the arcs that come after
make up a polygon completely within the polgon
What are the 2 common ways that vector data is stored? Describe them. - Answer -1.
Georelational (shapefiles)
-the spatial (arc, line polygon topology) and the attribute data (what it is, info about the
feature itself) are stored separately
2. Object-Based (geodatabases)
-Spatial and relational parts are stored in the same files; spatial features can have
properties and methods
What is the mixed cell problem? Explain some common solutions. - Answer -Mixed cell
problem: How do you assign values to cells that have more than 1 feature within it?
Some solutions:
-domination (whatever you are studying wins; if it is in the cell, that's what the cell is
marked)
-most common value (whatever is most common in the cell wins)
-edges separate (only mark cells that are 100% one feature; everything else creates a
no data "edge" between features
-Cell-Center (whatever is at the direct center of the cell is how the cell is defined)
What is the difference between discrete and continuous raster? Gives examples of
when you would use each. - Answer -For a discrete raster, values are integers; they
refer to a limited # of classes, and pixels that have to same value fall into the same
class
Ex: soil classes, vegetation classes
For a continuous raster, values are a floating point (i.e. Not necessarily all integers);
they wouldn't convert well back into a vector set
Ex: elevation, precipitation
A continuous raster is also called a [ ] - Answer -surface
Describe and explain the difference between the different ways data may be
compressed. - Answer --Sequential coding: there is no compression; it just scans lines
-Run-length: Trying to round up pixels of the same value; runs from left to right, down
each row
QUESTIONS V2 (2ND HALF MATERIAL)
Describe the 3 systems of georeferencing and give an example of how each one could
be used. - Answer -1. Metric: the location is defined using measures of distance from
fixed places; metric is the foundation of all 3
Ex: a GPS defines location based on their distance from a fixed location
2. Nomial: locations are defined with placenames
Ex: Hamilton, St. Clair River, Canada
3. Ordinal: Locations are ordered in some manner
Ex: Postal addresses: an area is given the first 3 characters, then each smaller area
within that area is given 3 more character, defining the area
Which of the following would not be well represented by a raster model?
Soil Properties
Elevation
Population
Precipitation - Answer -population
Which of the following would not be well represented by a vector model?
Population
Elevation
Soil quality
Population density - Answer -elevation
At least 2 [ ] define a line segment; one or several line segments define a(n) [ ]. Angle
points are [ ] and endpoints of a(n) [ ] are [ ] - Answer -points, arc, vertices, arc, nodes
What is topology? - Answer -the math of how features join
True or false: points, lines, and polygons cannot exist within the same vector layer -
Answer -True; they must each have their own layer
Describe the spaghetti data model - Answer -It lists coordinates, with lots of duplication;
there are no relative relationships encoded; it is just the point/line/polygon, and the
coordinates associated with it
Describe a node file in a topological data model - Answer -it is similar to a spaghetti
model in the fact that it lists the points and their associated coordinates
, Describe an arc file in a topological data model - Answer -It lists each arc #, the start
(F) node and the end (T) node, the vertices present (if any), and the polygon to the left
and right of it
Describe a polygon file in the topological data model - Answer -It lists the polygon #
and the arcs that make it up; if there is a 0, that means the the arcs that come after
make up a polygon completely within the polgon
What are the 2 common ways that vector data is stored? Describe them. - Answer -1.
Georelational (shapefiles)
-the spatial (arc, line polygon topology) and the attribute data (what it is, info about the
feature itself) are stored separately
2. Object-Based (geodatabases)
-Spatial and relational parts are stored in the same files; spatial features can have
properties and methods
What is the mixed cell problem? Explain some common solutions. - Answer -Mixed cell
problem: How do you assign values to cells that have more than 1 feature within it?
Some solutions:
-domination (whatever you are studying wins; if it is in the cell, that's what the cell is
marked)
-most common value (whatever is most common in the cell wins)
-edges separate (only mark cells that are 100% one feature; everything else creates a
no data "edge" between features
-Cell-Center (whatever is at the direct center of the cell is how the cell is defined)
What is the difference between discrete and continuous raster? Gives examples of
when you would use each. - Answer -For a discrete raster, values are integers; they
refer to a limited # of classes, and pixels that have to same value fall into the same
class
Ex: soil classes, vegetation classes
For a continuous raster, values are a floating point (i.e. Not necessarily all integers);
they wouldn't convert well back into a vector set
Ex: elevation, precipitation
A continuous raster is also called a [ ] - Answer -surface
Describe and explain the difference between the different ways data may be
compressed. - Answer --Sequential coding: there is no compression; it just scans lines
-Run-length: Trying to round up pixels of the same value; runs from left to right, down
each row
