6 Complications of storing Geography within a GIS

GIS software

Image 17: How does the GIS software know to draw a polygon for each feature within the digital boundary dataset? Let`s focus on the polygon labelled above as 35UCFS0001

The vast majority of the features held within digital boundaries appear as simple singly ringed polygons. There are exceptions that we need to be aware of.

Take a look at our digital boundaries sitting in the GIS again

The Output Area labelled 35UCGC0004 has a hole wheras the Output Area labelled 35UCGE0005 seems to be made up from more that 1 polygon parts. What is going on in each of these cases.