The link below is to an article that looks at how to read trail maps.
Australia roared into 2020 as a land on fire. The human and property loss was staggering, but the damage to nature was equally hard to fathom. By the end of the fire season 18.6 million hectares of land was destroyed.
So what’s become of animal and plant survivors in the months since?
Click through below to explore the impact Australia’s summer of fires had on an already drought-ravaged landscape and the work being done to rescue and recover habitats.
In recent days, many worrying bushfire maps have been circulating online, some appearing to suggest all of Australia is burning.
You might have seen this example, decried by some as misleading, prompting this Instagram post by its creator:
As he explained, the image isn’t a NASA photo. What a satellite actually “sees” is quite different.
I’ll explain how we use data collected by satellites to estimate how much of an area is burning, or has already been burnt, and what this information should look like once it’s mapped.
When astronauts look out their window in space, this is what they see:
It’s similar to what you might see from an aeroplane window, but higher and covering a wider area.
As you read this, many unmanned satellites are orbiting and photographing Earth. These images are used to monitor fires in real-time. They fall into two categories: reflective and thermal.
Reflective images capture information in the visible range of the electromagnetic spectrum (in other words, what we can see). But they also capture information in wavelengths we can’t see, such as infrared wavelengths.
If we use only the visible wavelengths, we can render the image similar to what we might see with the naked eye from a satellite. We call these “true colour” images.
Note that the image doesn’t have political boundaries, as these aren’t physical features. To make satellite imagery useful for navigation, we overlay the map with location points.
From this, we can predict where the fires are by looking at the smoke. However, the fires themselves are not directly visible.
‘False colour’ images
Shortwave infrared bands are less sensitive to smoke and more sensitive to fire, which means they can tell us where fire is present.
Converting these wavelengths into visible colours produces what we call “false colour” images. For instance:
In this shortwave infrared image, we start to “see” under the smoke, and can identify active fires. We can also learn more about the areas that are already burnt.
Thermal and hotspots
As their name suggests, thermal images measure how hot or cold everything in the frame is. Active fires are detected as “hotspots” and mapped as points on the surface.
While reflective imagery is only useful when obtained by a satellite during daytime, thermal hotspots can be measured at night – doubling our capacity to observe active fires.
This information can be used to create maps showing the aggregation of hotspots over several days, weeks or months.
Geoscience Australia’s Digital Earth hotspots service shows hotspots across the continent in the last 72 hours. It’s worth reading the “about” section to learn the limitations or potential for error in the map.
When hotspots, which show “hot” pixels, are shown as extremely big icons, or are collected over long periods, the results can be deceiving. They can indicate a much larger area to be under fire than what is really burning.
For example, it would be wrong to believe all the areas in red in the map below are burning or have already burnt. It’s also unclear over what period of time the hotspots were aggregated.
Considering all of the above, there are some key questions you can ask to gauge the authenticity of a bushfire map. These are:
Where does this map come from, and who produced it?
is this a single satellite image, or one using hotspots overlaid on a map?
what are the colours representing?
do I know when this was taken?
if this map depicts hotspots, over what period of time were they collected? A day, a whole year?
is the size of the hotspots representative of the area that is actually burning?
So, the next time you see a bushfire map, think twice before pressing the share button.
The link below is to an article that offers 7 tips for using Google Maps.
The link below is to an article that takes a look at the new Yahoo Maps.
The link below is to a useful map featuring Australia’s World Heritage sites.
My latest holiday plan has gone flop – the back packing holiday is a no-goer. Reason? It would seem from all reports that the Tops to Myalls Heritage Trail has been abandoned, with parts of the route now so overgrown as to be unrecognizable. I have been told of walkers in recent times having to back track a fair distance when the way ahead was no longer able to be walked. So as disappointing as it is I have abandoned the trail myself and will now do something else.
With time running out for a settled option, I have decided to fall back on an earlier idea and that is to visit the Cathedral Rocks National Park and possibly do some further walks at the Dorrigo National Park. I have booked a vehicle (car rental) for the trip so things are fairly settled now as far as the destination is concerned. I am now going to put some meat on the bones of my idea and draw up an itinerary, Google Map, etc. So some real detail of what I plan to do will be coming over the next few weeks.
This isn’t going to be an expensive holiday or a long one, but is mean’t to be a simple time-out break and one that will allow me to plan some much bigger holidays for later in the year and into the coming year also.
I am constantly looking at ways to improve the kevinswilderness.com website and add new content to it. With the success of the Google Map that was added to the page dealing with my recent road trip, I have decided to add Google Maps wherever they would prove useful – such as for locations, track routes, etc.
The first part of the site getting an overhaul with Google Maps in mind, is the Barrington Tops page. I am also adding new content to the page as I go. The Barrington Tops page is one of the biggest pages on my site, so the process is taking a bit of time. You will also find the planned itinerary for my backpacking camping holiday here as well as I move along with it.
Visit the page at: