The map results page provides an interface to spatially explore the collisions. Each of the sections on the page and the included functionality will be described in this article.
The Map Contents section on the left shows the collisions on the map, the city or county boundary, and any user added layers. The section can be hidden or opened by clicking on the Map Contents button.
The collisions can be shown as individual points, clusters, or as a heatmap by clicking on the specific tab. Descriptions of each are as follows:
Points: The default view displays each collision as a blue circle on the map. If you click the Points tab, you will also see several different symbolization options expanded below. This allows you to color the symbols according to various categories: By collision severity, by motor vehicle involved with, or by collision type. Each category shows the name and number of collisions of each type and by clicking on the type, they can be turned off/on in the map.
- Clusters: Clusters aggregate nearby collisions into single larger points.This helps to synthesize areas with large numbers of collisions. Clusters change color and size depending on the number of records represented in white text. Clicking on a cluster shows gray dots of each of the individually represented collisions and the details page can be accessed for each of them
Heatmap: When heatmap is selected, collisions will be displayed as a matrix of colors where the dependent variable is the density of collisions. Blue areas represent lower numbers of collisions while red areas represent the highest collision counts. Depending on the scale of your map, you may desire to adjust the blur radius. This adjusts how close pixels are determined to be related and can have a drastic effect on the output. You can adjust the blur radius by the slider control in the TOC.
The other layers section in the map contents contains a single jurisdiction boundary layer by default. Turn the boundary off or on using the checkbox.
In addition, the Add Layer button allows you to add an ArcGIS Server layer. for your jurisdiction. Simply paste the URL of your layer into the dialog and it will be displayed on the map temporarily during the browser session. This powerful feature allows you to reference collision locations next to your own data such as bus routes or other points of interest.
View Details Popup
The collision details also gives full access to all the raw data fields available for the collision at the bottom of the page. Click on the categories to expand each of the data types.
Map Tools - Select Collisions
A key feature of the map view is the ability to select collisions of interest in a region, corridor or intersection. After selecting the collisions you can download the complete data files or open a new results window to conduct further analyses. There are two different ways to select collisions:
The select by drawing tools allow you to draw a shape around the collisions that you want to select. Choose from either the Free Polygon (left) or the Polygon (right) tool. Click your mouse to draw around the collisions and let go to complete your selection.
The select by buffer tools can give more precise measurements. For example, you may want to select collisions within 50 feet of a corridor or 100 feet of multiple intersections. To use, simply enter a buffer distance and choose a shape design. Hovering over each of the shapes provides a description. Once selected, instructions are displayed as you click on the map.
The summary of the mapped collisions are displayed in the small window in the upper right corner. The number of mapped and selected collisions are shown along with several other potential options.
If you have selected collisions, the clear selection link will be activated. Clicking this will clear the selected collisions and drawing from the map.
Open Selection in a New Window
If you have selected collisions, the open selection in a new window hyperlink will be activated. Clicking this will open an entirely new results window with the full set of collision lists, tables & charts, map view and the collision diagram. The collision diagram is only activated via this option or by viewing a specific intersection history on the main query page.
Clicking the Download Collisions link in the Results box shows a pop-up window with several options
First, users should choose the extent of interest: All Mapped Collisions or Selected Collisions (disabled if no collisions are selected).
Next, the type of data file should be chosen: Collisions, Parties, or Victims. Typically, the collisions file will be of interest but you may also be interested in the Parties and/or Victims file.
Finally, either a Comma Separated (CSV) Table file or a Google KML file (KML file only available for collisions) can be chosen. Click the Start Downloading button to download the chosen file.
There are several different options for a basemap background. Click on the Basemap dropdown menu to see the options such as imagery or topography and others.
Go to a specific address or intersection, by typing the full address, city and state into the box.
This tool can be accessed from the map toolbar and allows you to calculate the area, distance or a latitude and longitude coordinate of a location.