Bounding Box VS Convex Hull

The KNIME workflow processes geospatial data of fires reported in Washington state since 2008.

To use the workflow, download and run it on the KNIME Analytics Platform. For optimal performance using the Geospatial Analytics extension, make sure you are using version 4.7.4 or higher.

The input data has been saved in the workflow data area, simply execute the components "Read Dataset" to obtain the necessary data.

After the data is loaded from the workflow data area, the workflow moves on to geospatial processing. The main objective is to create a convex hull and rectangle encapsulating fire incident locations. The Bounding Box and the Convex Hull nodes can create these geometries.

1) Rectangle:
The "Bounding Box" node creates a rectangle around the fire incidents. This node calculates the minimum bounding rectangle encompassing all fire incident points. The resulting rectangle is aligned with the latitude and longitude axes.

2) Convex Hull:
The "Convex Hull" node takes the input fire incident locations and generates a convex polygon that encloses all the points. This polygon represents the minimal convex shape that contains all the fire incident coordinates.

Once the convex hull and rectangle are generated, the workflow proceeds to visualize the results in a geospatial view.

The geospatial view can display the fire incident points as markers on a map, with the convex hull and rectangle overlaid. The visualization can be enhanced by incorporating additional information, such as fire incident attributes or time-based data, through colour coding, size variations, or pop-up tooltips.

External resources

• DNR Fire Statistics 2008 - Present