GISC9301 – Introduction to ArcGIS
Assignment #2
Data Classification – In-class Assignment
Question 1.
a) Three examples which can be classified under quantitative data include: The heights of players
on a football team, the values of homes in a neighborhood, and the percent grade of students in
a classroom.
b) Three examples which can be classified as categorical data include: Race, sex, and education
level.
c) i. The classification method chosen to represent the seven distinct neighborhoods in Thorold is
that of Equal Interval. The entire range would be equally divided into the number of classes
chosen and would include even the income data that contained no values. Equal Interval is the
most appropriate for familiar data ranges like the sets of income being evaluated.
ii. The classification method chosen to represent the Air Quality Index Data is Equal Interval.
Equal interval divides the range of attribute values into equal-sized sub-ranges. This allows you
to specify the number of intervals for the index. Equal Interval is most used for familiar ranges
which would apply to the air quality index.
iii. The classification method chosen to represent the student IQ’s given the mean and one
standard deviation is Defined Interval. By being able to define the interval size based off of the
ranges given proper classes can be given to appropriate classify the various IQ’s.
iv. The classification method chosen to represent the raster data set from the TERRA satellite is
Geometrical Interval. This method is used to create class breaks based on class intervals and is
used when there is little variance between classes to ensure the class ranges have the same
number of values.
d) For any frequency distribution histogram of classified data the y-axis represents a count of
features in a field.
e) For any frequency distribution histogram of classified data the x-axis represents the range of
values for the particular field.
f) When re-answering question 2c. from the previous assignment it is best to first show what I
wrote for my answer:
As the Health Department’s GIS consultant the first strategy to map out the excel sheet properly
is to symbolize the species in a distinct manner to ensure the positive or negative test results are
clearly visible. After the excel data is loaded into Arcmap, ensure that there are at least two different
types of species by opening the table of contents than the attribute table. Once completed close the
table and open the layer properties of Species. Clearly identify the ‘species’ by changing the value
field list, and selecting and appropriate color based on bird. Next a definition query should be created
to properly limit the display of birds to indicate the only potential infected ‘species’. Locate the query
builder and select the ‘Positive or Negative test results for West Nile virus’, than select unique values
and include the most appropriate ranges (based off of other values). This should create appropriate
points for each area municipality that has the greatest positive or negative test result. Open the layer
properties for ‘Positive or Negative test results’ and separate the value field list to properly identify
which results are positive and negative by color.
Given the information and from what I have learned in chapter 7 there are multiple steps which
could be taken to give the data a much different and more effect result. First I would use the natural
breaks method to classify the features into appropriate ranges with labels. This method would use
the natural groupings inherent in the data to create intervals and gaps. This method would be
beneficial for the unevenly distributed data across the 12 distinct areas. Next I would change the
quantities graduated colors to properly indicate areas that have positive or negative test results to
better demonstrate the different areas infection rate. Next I would change the graduated symbols
to match the species of bird found dead in that area to show the range of birds who have contracted
the West Nile.
Question 2.
a) The total surface area for the Niagara College Glendale Campus building is 6494.51m2.
Figure 2.1 Shows the record of the Glendale campus inside an attribute table.
Figure 2.2 Shows Niagara College under heads-up digitizing.
b) The total building footprint size is 1952.57 meters squared. This can be seen by adding the
Greenhouse Facility office area and glassed area together as demonstrated by the attribute
table below.
Figure 2.3 Shows the Niagara College Greenhouse Facility attribute table.
Figure 2.4 Shows the Niagara College Greenhouse Facility split into two.
c) The area of the lagoon south of the campus was found by digitizing. The picture below
demonstrates the digitized lagoon. Using the attribute table from the digitized lagoon the
23652.91hectares. The perimeter length can also be found which is 775.26 meters.
Figure 2.5 Shows the Niagara College Lagoon digitized.
Figure 2.6 Shows the attribute table of the Lagoon without the berm.
Next to get the Berm added to the attribute table, the sketch properties needed to be edited so that 9
vertices remained, which could be moved around to create the final shape area including the berm.