NRSC 2230 / GEOG 2750

Module E: Basic Spatial Analysis


Learning Outcomes

Upon successful completion of this topic you will be able to:

  • Describe the type of questions answered by spatial analysis
  • Explain the functions of Boolean Operators
  • Explain the functions of Conditional Operators
  • Explain the basic Map Overlay operations
  • Perform Attribute Queries using ArcGIS
  • Perform Point-in-Polygon Queries using ArcGIS
  • Perform Line-in-Polygon Queries using ArcGIS
  • Perform Polygon-in-Polygon Queries using ArcGIS

Analysis is performed in order to provide relevant information to help in decision making.  The key questions that must be answered before the analysis can begin are:

1) What is the purpose of the analysis

– what decisions are to be made

– what information (substance and format) do these decisions require

2) What approaches are to be taken to generate the information

– what detailed technical questions are to be asked (working in reverse helps in avoiding unnecessary queries)

– eg, Is an evaluation of constraints required? (potentials,  EIA)

3) What analytical techniques should be used

– what specific techniques provide data at the desired accuracy and reliability levels ( subject to data availability, money and time constraints)

Activity 1 – Describing your problem

Write a post in your blog that describes one analytic process that you are involved with in your area of study.  Pay specific attention to the issues discussed in Question 1 above ie those related to the purpose of the analysis.  Please read the postings of the other members of the class as you may be required to do further work on a problem other than your own.

Activity 2 – Describing the Approach

You will be divided into groups and will be assigned one of the processes described by a classmate.  As a group, you will discuss the problem. Each student will post a description of the approach taken and any suggestions for a different approach.  If you are satisfied with the current approach, explain why.

Activity 3 – Query by Attribute

This activity allow us to query the dataset to identify features that contain a specific value(s) in one (or more) of its attributes.  The following shows how to select the paved roads in our Road layer.

  • Load the desired Layer from the appropriate Directory into ArcMap
  • Go to the Selection Menu and choose Select By Attributes….
  • The Select By Attributes dialog Box should appear
  • Ensure that
  • Layer: Desired
  • Method: Create a new selection
  • Double Click <Field_of_interest> from the field list (It  appears in the text box below)
  • Click Get Unique Values: button to see all unique values in the field <Field_of_interest>
  • Click on the equal sign (=) button
  • Double click on the value of interest in the Values list
  • The textbox below should show <Criterion>
  • Click OK


Your queried feature should show in the colour blue.


Activity 4 – Query by Location

This activity enables us to identify features in one dataset based on their locations in respect to another.  The following will identify the features in one theme that are located within 5 km. of the boundary of a feature in another theme.

  • Load the two Layers into ArcMap
  • Go to the Selection Menu and choose Select By Location….
  • The Select By Location dialog Box should appear
  • Ensure that the dialog is as follows
  • I want to:
  • Select features from
  • Check the box indicating the first theme
  • that
  • choose “are within a distance of
  • the features in this layer:
  • choose the second layer
  • of:
  • Input 5
  • change units to kilometers
  • Click OK

Activity 5 – Further Queries by location

Identify the roads and rivers from the Provincial datasets that fall  within 5 km of the ????? area.

Activity 6 – Buffering Features

View the Youtube video that provides a tutorial on buffering features.

Activity 7 – Intersect by Overlay

View the Youtube video that provides a tutorial on the intersect function.

Activity 8 – Union by Overlay

View the YouTube video that provides a tutorial on union function.