Question 1: Data Structures and Scaling
a.) What is the difference between Integer, Byte, and Real Number data types? [1 mark]
Integer data have no fractional parts and only increase by whole number increments. This can include numbers from – 32768 to + 32767.
Byte data is a sub-type of integer and only includes positive integers 0-255. Byte files only require one byte per cell, whereas integers requires 2, meaning byte data requires only half of the storage space that integer data requires.
Real Number data are those that may contain fractional parts and they require 4 bytes of storage for each number.
b.) What is the difference between ASCII and UNICODE, and why is ASCII a more common GIS data type? [2 marks]
ASCII is the American Standard Code for Information Interchange format which formats alphabetic characters, numerals and symbols. It stores single byte codes and is a subset of UNICODE.
UNICODE is a new formatting system that copes with non-US alphabet systems (such as Greek. Chinese and Arabic characters).
Yet, ASCII is a more common GIS data type because it is used to facilitate import and export and only requires one byte of memory, where UNICODE requires more storage.
c.) Give an example of when a quantitative bipolar palette is appropriate. Give an example of when a quantitative ramp palette is appropriate. Give an example of when a qualitative palette is appropriate. [3 marks]
A quantitative bipolar palette is best when creating a map that has distinct values that can be represented by two or more colour groups, so for example a map that shows houses that have pets and those that do not.
A quantitative ramp palette is appropriate when creating an elevation map as it can easily represent an increase in values of some set variable.
A qualitative palette is appropriate when working with maps that have details about the type of forest cover in a specific area as these palettes represent various values that each have distinct attributes.
Question 2. Working With Vector Layers
a.) What is a quantile and why is it sometimes advantageous to use them? Give another example of when quantiles would be a better classification method than a linear colour ramp. [3 marks]
A quantile is a way to split data sets into groups (or classes) of equal size. It is advantageous to use when you have highly skewed distributions or outliers as it creates a more linear gradient in your dataset. It allows you to see more variation within the middle of the dataset instead of having a representation of skewed data that focuses on the highest and lowest values. This way, all values are equally represented instead of just the outliers. Another example of when quantiles would be a better classification method than a linear colour ramp would be a map that showcased air pollution levels of all countries in the world. This way, all of the values would be split into equal groups and represented evenly instead of all values within the middle looking as though they had no variation due to the skew of very high or low outliers.
b.) What is the name of the town in the database table with the greatest population in the year 2000?
The town with the greatest population in Massachusetts in the year of 2000 was Boston.
c.) What is the 1980 population of the town with the greatest area? [0.5 marks]
In 1980, the town with the greatest area in Massachusetts was Plymouth.
Question 3. Analysis and SQL
a.) How many towns are there in total? How many towns have a population change greater than zero between both 1980-1990 and 1990-2000? [1 mark]
There are 351 towns in total. There are 249 towns that have a population change greater than zero between both 1980-1990 and 1990-2000.
b.) You calculated a new field [PopCh80_00] in the ‘Calculate’ section of the exercise. What is this and what are the units of measurement? [2 marks]
A new field is another column of data that you are creating on the database workshop table. This specific field that I created using a SQL calculation shows the population change from 1980 to 2000 measured as a percentage.
c.) Use the cursor inquiry tool to find the name of the town with the greatest population decline. What is the name of this town? Why do you think it has experienced such a drastic population decline between years 1980 and 2000? [2 marks]
The town with the greatest population decline is Harvard. The big decline in population occurred between 1990 and 2000 as the population change between 1980 and 1990 was not very large. I think that it experienced such a drastic population decline after 1990 due to a large migration out of the town. This was due to the closure of a military base, Fort Devens, which had many members and their family living in the area. After the closure of this Fort, the families relocate to other areas which could explain population growth in other towns nearby.
d.) Create a map composition of the map you created in 3c, using MS PowerPoint. Submit this as a separate page, including all necessary map elements. [3 marks]
Bonus Mark: include a text label on your map for the name of the most prominent peninsula. [1 mark]
This map can be found under the next blog titled “3.d.) Massachusetts Population Change Map”
e.) How many hospitals and schools are in Massachusetts, according to the database file? [1 mark]
There are 145 hospitals in Massachusetts and 2521 schools in the State according to the database file.
f.) Which town experienced the greatest growth between years 1990 and 2000? Why do you think this is? [2 marks]
The town that experienced the greatest growth between 1990 and 2000 is Boston. I think that this is due to the fact that Boston is the capital city of Massachusetts and this is when a lot of urbanization was occurring. People typically wanted to be a part of the big city and be closer to large institutions and amenities, such as Universities and public transit.
g.) Complete the ‘challenge’ section on page 55 of the tutorial. [3 marks]
Works Cited
Eastman, Ronald J. TerrSet. Version 18.31. Worcester, MA: Clark University, 1987-2017.
GEOG 355 