Equal interval divides the range of values (from maximum to minimum) into “x” number of equal-sized ranges, where “x” is decided by the GIS analyst. This is the default method on ArcGIS and algorithms mathematically “decide” what these natural groupings are. Natural breaks classifies data based on natural groupings inherent in the dataset. There are many methods of data classification, but the four most commonly used are: The range of values for each class of data is determined by the method of data classification adopted when constructing the map using the GIS software. But in the case of the range of values for each class, how is this determined? Generally speaking, not more than five classes should be used to categorize the data because anything more would make it difficult for the map user to distinguish between the different shades of colour accurately.

The cartographer or GIS analyst often have to make important decisions regarding the number of classes to categorize data into, as well as the range of values within each class. different shades of a colour to indicate different levels housing affordability in Metro Vancouver. Often times, maps will show distinct visual differences between ranges of values (or classes) for a specific type of data, e.g. Working with ratios to compare datasets, and normalizing data to determine housing affordability.Ĥ. Understanding quantitative data classification, and creating a map to illustrate the difference between four methods of classification:ģ. Terms of Canadian Census Data collection.Ģ.Downloading Spatial and Tabular Census Data.Developing a working knowledge of Canadian Census Data: This post is about topics explored in the fourth GIS laboratory session, which had the following learning objectives:ġ.

Classification method map