Where is the Legend?
A standard cartographic document or map has three elements that are required to be included for understanding the content. These are the Title, Legend, and North Arrow. If you are taking a class in map-making, and you leave any one of these off of your map, then you get an "F".
Standard maps are used to show locations and their relationship to one another. At Clark County GIS we usually make maps that represent locations with values or names. We might produce a map showing the assessment value of properties in a neighborhood. Another type of map would show the location of parks, trails, and recreation. These maps usually have a legend, a scale, and title.
Clark County GIS is also responsible for maintaining infrastructure information for our partners. That means keeping track of the location of sewer manholes, water pipes, roads, houses, and other real items that are useful to the effective and efficient operation and maintenance of local government. These maps help operations crews and managers find fire hydrants, bridges, and driveways. These maps usually show distinct features as points, lines, or areas to represent the thing being mapped.
HEAT MAP (density)
However, there are other ways of looking at data, if you want to plan or see trends in the landscape. One method is called a HEAT MAP. The heat map is just a density map, showing the congregation of features or activities. These types of maps are called VISUALIZATIONS. Often, they do not fit the standard mapping practices of legends, scales, and units. They are extremely useful in spotting patterns.
Here are four examples of Heat Maps:
This map shows the density of residential housing in Clark County, Kentucky. Notice the purple and pink colors inside the city limits of Winchester. The Pink-Purple-Dark Blue areas are more densely populated than the lighter blue areas outside the city.
This map shows the density of vehicular accidents in Clark County, Kentucky. You can see a trend around certain intersections. Visualizing the crash information like this can help plan better traffic control and enforcement efforts.
This map shows the density of historic sites in Clark County, Kentucky. Displaying the historic locations, in this way, can help planners and the public preserve the heritage of Clark County and allocate resources to areas that can boost tourism based on historic interest.
This map shows the density of sanitary sewer infrastructure around Winchester. This representation shows the density of development in a different way. It can show where the infrastructure is built and lead to better planning of maintenance and replacement efforts.
The Heat Map is just one way to visualize data in a way that is visually appealing and not highly technical. I hope to post more examples of these types of maps in the future.
If you have a Heat Map that you would like to see created and posted, then submit a comment via our comment form.