As part of our tool series, this article will discuss a fundamental tool you may have never heard of, called the Minimum Bounding Geometry. I recently helped a client with a simple request. They wanted to have a polygon drawn around groups of points by an attribute value but didn’t want to construct the polygons manually. The client had already tried Heat Map symbology in ArcGIS Pro, but it didn’t produce the needed results. If you don’t know much about heat maps, Esri has some excellent documentation and examples out there. Heat map symbology is used mainly when you have many points clustered together and need to visually see density patterns graphically. The example below was constructed in ArcGIS Pro 2.1.2 by the City of San Diego’s Engineering and Capital projects department.
As you can see, the Heatmap symbology shown in the application displays a pattern of the amount of work for CIP projects that are within close proximity for the selected time frame.
The client I worked with didn’t need to see a pattern visually. Instead, they needed to have static boundaries around groups of utility poles with the same type of attribution and have the polygon contain that attribution type, such as a watershed or zoning map. That way, they could create a new polygon feature class. Due to the client’s request, the alternative solution was the minimum bounding geometry in the features toolset of ArcGIS Pro! The minimum bounding geometry tool will draw different types of polygons (rectangle, circle, irregular, etc.) based on the parameters chosen. Esri’s documentation illustrates the variety of possible outputs based on the user’s specified geometry type and grouping choices.
The client wanted a reasonably tight bounding polygon around their groups of points based on a selected attribute. The “Convex Hull” option did just that, giving the client the desired result and saving a lot of time. The client could then use the output for additional queries, intersects, and needed reports.
The minimum bounding geometry is very simple yet powerful! It only has a handful of parameters, but the “Geometry Type” parameter is where you’ll specify what type of output polygons will represent your input feature.
Once you select your geometry type, you can then specify how your input features will be grouped. We checked the box for “Add geometry characteristics as attributes to output” because the client needed the geometric attributes from the input feature to be in the output feature class. By default, this is unchecked. Click run and this tool will produce an output polygon feature class for you, preventing the headache of manually constructing a polygon!
So to wrap it up! If you want to look for patterns in your data, heat maps are for you! If you want to create a static boundary around your data, you may want to consider the minimum bounding geometry tool! If you need assistance in ArcGIS Pro or want to see if we can speed up your manual process, reach out via e-mail today! We would love to talk with you and make your life a little easier!
