Crime Locations in Victoria, BC: Random or Patterned?

Introduction

* Crimes in Victoria, BC: Are they randomly located or is there a pattern?
* Crime in the City of Victoria ...
* Though the City of Victoria is relatively low on crime [CITE ???], the Victoria Police Department are regularly requesting a larger budget to deal with the increasing rate of downtown homelessness(???) and associated crimes?? [CITE ???]
* In 2018 there were [???] crimes, of which [??? % were ... list parent incident crime types here] . Explore the interactive map in figure 1 at the top of this page to view all of the 2018 crime locations. [CITE dataset stats]
* While potential crime scenes are being secured, assessed, and police reports initiated, bright orange Police Tape may be used as a visible barrier, as seen in figure 2.

* "An interesting intro paragraph to provide context to the topic"
* "Description of crime situation in the city"
* "use government and/or police reports" [cite sources]
* "descriptive statistics from dataset"

"Write a brief paragraph explaining the objective of this project. Do not mention that it is part of an assignment; instead, focus your writing on the public who can learn something from your work. In this paragraph, you should describe your objective, how you will accomplish this objective, and why it is important to conduct this work. Do not get into the nitty-gritty details here (don’t mention R or specific methods or equations). Instead, this paragraph should be easily understood by a general audience."

Objectives
  • Are specific types of crimes randomly located?
  • If not, where are the highest incidences of crimes?
 Intro Marking Matrix
  1. Description of crime situation in the city [1]
  2. Citations included and adequate (at least 2) [#1] [2]
  3. Image included [1] - DONE
  4. Clearly state objective [2]
  5. How will you accomplish objective? [2]
  6. Why is this research important? [2]
An orange Police Tape, reading: Police Line Do Not Cross, spans the width of the image as it acts as a barricade to secure a potential crime scene behind it.

Figure 2. A length of bright orange Police tape
acts as a barricade to secure a potential crime scene.
[Image Source: Victoria News, 2019-07-23 #1]

Study Site: City of Victoria

"Write a brief paragraph explaining the City of Victoria"

* Victoria Police Department provides police service to both the City of Victoria and the Township of Esquimalt [#6].
* Victoria, on Vancouver Island, the captial of the province of British Columbia
*
*

* In the most recent 2016 census, the population of the City of Victoria was 85,792, having grown 5,774 from the previous census in 2011, with a population density of 4015.7 people/km², 25% of whom are over 65 years of age. Victoria is also the largest municipality in the Capital Regional District, with 22.38% of the 383,360 2016 population Greater Victoria Area [#2].
* According to the spatial geometry of the City of Victoria boundary shapefile, the city includes a total area of 21.36 km² [#3].
# [#4]

About Victoria Marking Matrix
  1. Background to City of Victoria and Crime [5]

Data

Crime statistics, from January 2011 to September 2019, were downloaded from the Victoria Police Department, in a csv file organized by the incident id and case number, and include the incident date and time, type of incident grouped within 18 different crime categories, as well as the address and location coordinates, resulting in a file containing 137,530 different crime data location points [#5].

The City of Victoria's perimeter boundary was needed to trace the exact extent of the city boundaries. Th boundary coordinates are available in the form of a polygon area shapefile, projected in UTM zone10, in the coordinate system NAD83 GRS80, and were downloaded from the City's open public data portal [#3].

The slideshow located in Figure 3 shows a series of screenshots of the 2018 crime dataset, which has been separately mapped to show each group of theft crimes, as well as a map which includes all crime types

Data Marking Matrix
  1. Provide a description of data source and contents [5]
  2. Any other Data??? ...

 

Figure 3. For each of the different levels of 2018 City of Victoria Theft Crimes, screenshots are displayed in a slideshow. The images include all crimes, as well as theft, theft of a vehicle, theft from a vehicle, robbery, property crime, and breaking & entering [#5]. Clicking the right or left arrows, or the lower dots, will change the image to next slides.

Analysis

During 2018, the Victoria City Police have incidence reports filed for 13,712 crimes in the City of Victoria [4]. The Open Street Map at top of this webpage (see figure 1) is an interactive leaflet map showing all of these 2018 City of Victoria Crime data points (to reset the map to the original extent after exploring the data, simply reload this webpage).

The data first needed to prepared for analysis, as this study is only interested in analyzing the 2018 City of Victoria Police crime statistics, so the crime points data needed to be subset to include only those crimes that occured during the year 2018, and include only the information we needed to analyze the data set, including the date, location coordinates and crime type. Also, as the Victoria Police serves both Victoria and Esquimalt, the City of Victoria boundary shapefile was used to create an intersection with the crime data points, bounding an extent that will include only the crimes in Victoria. In order to find the density of crime points, the area of Victoria first needed to be calculated, which was be done in two ways, with both ending up with different values. Calculating the spatial geometry of the shapefile polygon follows the coastal outline with a bit more exactness, resulting in the larger area of 21,363,930 m², than simply relying on the shapefile-defined area of 21,347,203,m²

In order to determine if the crimes in Victoria were randomly located or had some significant spatial pattern, each separate crime incident was grouped into 18 different incident types, upon which a series of four point pattern analysis tests were done on the data to determine if there were any statistically significant results that could help us answer this question.

  1. Nearest Neighbour Distance
  2. Quadrat Grill Cell
  3. K Function
  4. Kernel Density Estimation

"Write this section as a narrative rather than as a methods and results section. It can be very boring for the general public to read equations and try to understand the math behind everything, therefore you need to clearly and concisely explain the methods you used and what they produced. I recommend having two main sections, each focused on one of the two questions posed by your supervisor"



Are Crimes Randomly Located?

* "provide a few sentences explaining each method you use and what it does"
* "provide" a brief paragraph describing the results."

The Nearest Neighbour Distance test was run to calculate the average distance between each neighbouring crime type point and comparing this distance to that of a randomly located neighbour, based on the density of the number of each particular crime type points in ratio to the area (21,363,930 m²). If the average distancer was equal to the random distance, the crime locations would be random, however, if the resulting z value confidence level was 95% or higher, those crimes would not considered to be random. If the mean distance was greater than the random distance the pattern would be a dispersed pattern, and if less would be a clustered pattern.

"*IMPORTANT: for the nearest neighbour analysis, you NEED to include the n and the area of the study site. You can include these in the text when describing this method."

The next test was the Quadrat density test, where the area is divided by a grid of cells, and the density of points is calculated for each quadrat. Choosing the number of quadrats can affect the test results, as if the quadrats are too small, there will be many cells with no points, and if they are too large, any change in point density over a small area may be difficult to see.

The K-function test ...

The Kernel Density Estimation

The crime types that were significantly randomly located were: Alarm, Arson, Assault, Assault with Deadly Weapon, Community Policing, Drugs, Robbery, Theft of Vehicle, Vehicle Stop, Weapons Offense



Where Are The Highest Incidences of Crimes?

* "few sentences explaining each method & what it does"
* "brief paragraph describing the results."

If crime locations are not random, they will have a significant pattern, which could be either dispersed (points equally spread over area) or clustered().

Stastically speaking, the crimes that were considered to have a distributed pattern, that was non random were: Breaking & Entering, Disorder, Liquor, Other, Property Crime, Theft, Theft from Vehicle and Traffic.

Analysis Marking Matrix
  1. Use appropriate methods for each question [4]

  2. Describe nearest neighbor analysis method [3]
  3. Provide necessary outputs [3]
  4. Describe nearest neighbor analysis results [3]

  5. Describe k-function method [3]
  6. Provide necessary outputs [3]
  7. Describe k-function results [3]

  8. Describe quadrat analysis method [3]
  9. Provide necessary outputs [3]
  10. Describe quadrat analysis results [3]

  11. Describe KDE method [3]
  12. Provide necessary outputs [3]
  13. Describe KDE results [3]

Limitations

* "Describe anything that the reader should be aware of with your finding."
* e.g. "did the number of quadrats in the quadrat analysis or the bandwidth in the KDE impact your results?"
* "don't make it sound as if your methods are bad."
* "make the reader aware of anything that they need to consider when making sense of your findings. Be honest, but not overly self-critical."

One limitation that affected the Nearest Neighbour Distance test was in the choice of one out of two the City of Victoria area calculations, and by choosing the area that used a more refined method which resulted in a larger area, creating a lower density of crime location points per unit area, which may have underestimated the significance of spatial patterning. ?????

Another limitation - Scale ??? when does dispersed become clustered ?? ......

Another limitation - This study does not test to see if any of these different crimes are related .. [CITE Jessica's Alcohol Access & Crime] ....

Another limitation ......

Limitations Marking Matrix
  1. Describe at least two limitations with methods used [5]

The Takeaway Summary

"Write a paragraph that summarizes your findings from the previous section. This is where you pull everything together to answer your two questions you ask in the opening paragraphs. Don’t just reiterate what you wrote in the Analysis section. Instead, write an interesting summary that brings it all together."

"For your final paragraph, provide a takeaway message for the reader. What has this analysis revealed? What could be the possible drivers of what your results show? Do these findings agree or disagree with conventional wisdom (provide citations for conventional wisdom). This is the paragraph that people will remember after reading your report, so it has it be clear, impactful, and provide insight into this topic."

Takeaway Summary Marking Matrix
  1. Summarize findings [4]
  2. Clearly answer both questions [4]
  3. What has analysis revealed? [4]
  4. What could be drivers of results? [4]
  5. Do findings agree with conventional wisdom? [4]

References

(To return to the referenced text, click the link in the reference number)


1. Depner, Wolf. (2019, July 23). Greater Victoria sees crime severity index rise. Victoria News. [news article: photograph]. Retrieved 2019-09-30 from https://www.vicnews.com/news/greater-victoria-sees-crime-severity-index-rise/

2. Statistics Canada. (2017). Victoria, City, British Columbia and Capital, Regional district, British Columbia, Census Profile, 2016 Census. [table]. Retrieved 2019-09-30 from https://www12.statcan.gc.ca/census-recensement/2016/

3. City of Victoria. (2019). City Boundary for Victoria, BC. [shapefile: 2019-09-21]. Retrieved 2019-09-23 from http://opendata.victoria.ca/datasets/city-boundary/data

4. Statistics Canada. (2019). Incident-based crime statistics, by detailed violations, Canada, provinces, territories and Census Metropolitan Areas. [Table: 35-10-0177-01]. Retrieved 2019-10-01 from https://www150.statcan.gc.ca/t1/tbl1/en/tv.action?pid=3510017701&pickMembers%5B0%5D=1.38&pickMembers%5B1%5D=2.1

5. Victoria Police Department. (2019). Victoria (BC) Police Department incident dataset. [csv file: 2019-09-21]. Retrieved 2019-09-23 from https://moto.data.socrata.com/dataset/Victoria-BC-Police-Department/f42u-v6f3

6. Victoria Police Department. (2019). About Us. [webpage]. Retrieved 2019-10-06 from https://www.vicpd.ca/?q=about-us

LAST EDITING

  1. CHECK REFERENCE NUMBERS IN TEXT
  2. CONSISTENT APA STYLE
  3. SPELL CHECK !!

References Marking Matrix
  1. Suitable style [3] - DONE
  2. Consistent [2] - DONE
 Writing Marking Matrix
  1. Text is in paragraph format [3] - DONE
  2. Text is **FREE OF SPELLING** and grammatical mistakes [4]
  3. Text is in logical order [3]