Creating a Buffer Analysis in QGIS

Buffer’s are a tool used to calculate the distance from an object or set of objects in an environment. In GIS, buffers are ideal for analysis’ that involve distance constraints. Some examples of these would be the proximity of an endangered species to urban development or tracking the extent of nuclear fallout. Buffers can be very versatile and are able to provide distances with both raster and vector data (points, lines, polygons) by creating polygons around your designated input features. Additionally, you can either use a fixed width buffer, such as the endangered species example provided above, or a variable width buffer, such as the nuclear fallout example where wind conditions may affect the extent of the area over time. There are countless buffer tools and methods spread across multiple GIS platforms such as ArcGIS Pro/Desktop, QGIS, Maptitude and many more that are all useful.

Purpose

The purpose of this demonstration is to show users a step-by-step process on how to use the QGIS plugin ‘multi-distance buffer’ in QGIS. This GIS procedure that will be demonstrated is a buffering/overlay tutorial which will show the minimum distance required for installing septic systems from various lakes in Quebec cottage country. The step-by-step process will cover how to download/install the software along with the data, the steps required to create the buffer(s) as well as composing the final map.

Software/Data

The goal of this demonstration is to utilize open-source software and therefore, QGIS will be the one of choice given its versatility and range of buffering options.

Software: This tutorial used QGIS 3.16.14 (long term release). You may use the latest version on QGIS for this demonstration. However, given the Multi-distance buffer plugin that we will be using is not native to the software, you may encounter difficulties in future software releases.

Data: Inhabited places: (https://open.canada.ca/data/en/dataset/1f3b874d-f881-4a6c-86ac-cfba856dfafc) Provinces/Territories, Digital Boundary File - 2016 Census: (https://open.canada.ca/data/en/dataset/47bd4f2e-1c77-49f8-8406-dc4dca64ee6b) 2016 Census Road Network File: (https://open.canada.ca/data/en/dataset/57d5ffae-3048-4a19-9b4c-eab12f6322c5) Water File - Lakes and Rivers (polygons) - 2011 Census: (https://open.canada.ca/data/en/dataset/448ec403-6635-456b-8ced-d3ac24143add#rate)