GIS (Geographic Information Systems) is a computer-based tool enabling the viewing, storage and querying of map-based information – i.e., info about some portion of the earth. A GIS stores information about features of the earth as separate map layers. Some examples are features such as vegetation, roads, towns, rivers, or burnt areas. Because these features are ‘mapped’, or related to the earth’s surface, they can be overlaid on top of each other (as in the picture example below) to display and answer questions about their relationship to each other.
Types of GIS used in bushfire management
- Web GIS: online, map-based sites such as Google Earth and Google Maps, NAFI, FireWatch, Sentinel EO Browser, ArGIS Online.
- Desktop GIS: software sitting on a computer. Some examples include ArcGIS, QGIS and BaseCamp™ – there are many others. These programs are generally quite powerful and used for querying map layers and creating maps. Some of this software such as QGIS and BaseCamp™ are free, others like ArcGIS require a licence.
- Field GIS: includes tools and programs that enable the user to record map-based information onto a tablet or GPS whilst out in the field. Some common examples of field software used in bushfire management in Northern Australia include CyberTracker™, Avenza Maps, and ArcGIS Survey123. These programs all run on a mobile device with GPS, or location-recording, capability.
More detail about different the different types of GIS used in bushfire management is discussed in NAFI for Fire Managers NT.
Types of map information used in bushfire management
There are a number of different types of map information that can assist with bushfire management. These can include:
Digital topographic maps: these are maps of the earth’s features provided by the government. They include information about man-made features (e.g. roads, airports, places), water features (rivers, swamps, streams), and land-based features such as vegetation and hills.
For example, the topographic map below of the Cobourg Peninsula, shows features such as roads (red lines), rivers (blue lines) vegetated areas (green), and places (black circles).
Points from the field: point data refers to specific locations on the ground. The most common type of point information used in bushfire management is ‘hotspots’. These points indicate the location of an active fire, as detected by satellites in the sky. Point/track information can also be recorded in the field on a GPS and could include the start or end points of a burning run, or tracks recording burning routes.
This map, from the NAFI website, shows hotspots or active fire locations (blue points), with a topographic line map in the background. The time of each hotspot can be determined from the accompanying legend.
Satellite imagery: High-resolution imagery can be used to view burnt area and active fires in many ways. The imagery below was derived from Sentinel 2 satellite imagery and shows different ways we can use this imagery to detect and monitor fires in the landscape.
True Colour Imagery – what we would see if we were looking down from a satellite. In this image you can see smoke plumes coming from active fires.
Imagery using a Middle Infrared Burn Index (MIRBI) highlight areas recently burnt.
Short-wave Infrared Imagery highlights recently burnt areas and active fire fronts allowing fire managers to monitor active fires.
Burnt area maps: GIS software uses algorithms which allow fire mappers to extract burnt areas from satellite imagery and create fire history layers. The advantage of burnt area maps is that you can calculate area burnt and other information.
The image on the left shows burnt area in red on a Landsat image. The image on the left is the same burnt area mapped, with burnt shown as black and not burnt shown as white.
On the NAFI website, these areas are displayed in different colours depending on the month in which they occur.