GPS + GIS = amazingly accurate mapping at SESL
Every now and then a new technology radically changes the way we do things. When mobile phones became affordable, suddenly tradesmen could take calls wherever they were, and now even little schoolchildren use them.
Two technologies that have been maturing over the past few years – GPS (the Geographical Positioning System) and GIS (geographical information systems) – have now converged in a way that makes land use planning so much easier and so much more accurate than ever before. SESL has adopted this new way of working, and all we can say is “Wow!”
The bad old days
Until recently, if you needed a site survey (for example, you’re building a house; you’re subdividing land; you want to apply fertiliser cost-effectively; you want to drain boggy ground; you want to know where rare plants and animals live; you don’t want to plough up a Telstra optical fibre cable), you would call in the surveyors. These hardy souls would trek through the wilderness to find the official survey marker, and then spend days or weeks taking readings with theodolite and compass, drawing on maps, and using trigonometry to plot everything. Then they would transfer everything to a new map for us to work from. We would then trek out across the same wilderness with the map, a compass and a tape measure and collect soil samples, for example. And it got tricky when the tape measure wasn’t long enough.
Meanwhile, site markers would be disturbed – by bushfires, cattle, landslips and cranky neighbours. Errors could slip through unnoticed. And if the planning authorities thought of something else later, everyone would have to trek out again.
GPS
The US military developed GPS in the 1970s. We’ve covered GPS in a previous issue of Fertile Minds.
Since the relaxation of signal encryption in 2000, civilian uses of GPS have blossomed around the world (although the US military reserves the right to encrypt signals again in the event of war). With the development of receiver technology and the introduction of a Russian system working in parallel (a European system is under development too), it is now possible to pinpoint your position anywhere on Earth’s surface to within 5 m, sometimes less.
Mobile phones now come with GPS capabilities as standard, and with the development of new software for both mobile phones and GPS receivers, it is now possible to record your movements metre by metre anywhere you want, and to record any other information you like with each point; for example, photos, weather readings, comments, soil profiles.
GIS
Surveyors and planners have been using computerised GIS for about 50 years now. A GIS can be thought of as a collection of data (latitude and longitude, altitude, rainfall, population, soil type, moisture content, language spoken, anything you like) associated with places. With a properly set up GIS, you can map the spread of a disease, plan a new subdivision, track crime, predict flood risk ... the list is endless.
GPS + GIS = !
The convergence of these two mature technologies has suddenly made our work a whole lot easier and more accurate in one go.
Since a few months ago, our work practices have changed radically. The Australian and NSW governments have begun releasing decades of data for public use. We can now download site information for your property as a starting point for a survey. To this we can add GIS data collected by your local surveyor. Even before we set out to visit you, we know the landforms and soils we’ll deal with.
On site, we can find the exact points the surveyor visited (to within 30 cm!). We can take soil samples from exactly the same point year after year. We can drive along boundaries, survey lines or easements and record the latitude, longitude and altitude every metre if we like. Every tree, every shed, every bog can be recorded. From the government data, every bore, every road and every creek can be added.
Back at the lab we analyse the samples and enter all the data associated with each point; for example, soil texture every 5 cm by depth, soil moisture, crop composition and fertiliser history. All these data can then be plotted on an aerial photo or a map of your property, either together or separately. The GIS software will automatically calculate boundary lengths, areas and setbacks. Do you want a map of the soil types on your property? Done. Do you want a history of the land use for the last hundred years? Done. Do you want to know where to apply phosphorus without wasting money? Done. In 3D? Sure. Weed infestations, salt concentrations, selenium deficiencies, acid sulphate soils, bushland, potential koala habitat, slope and aspect, water table depth, soil erosion potential, soil contamination, vegetation height, standing biomass ... the only limit is your imagination.
DIY
With the data set we’ve compiled and a GPS receiver, you can visit the same sites we’ve visited and make your own assessments. And if you’ve invested in or hired a GPS-controlled tractor, you can use the same coordinates to apply fertiliser or seed exactly where it is needed. In fact, researchers in Japan are developing robot-controlled tractors that use GIS data under GPS control to carry out all crop operations autonomously. All the Japanese farmers will need to do soon is open a beer.
The future
Jobs that would have taken us days in the past now take us hours – although we still have to get out of the vehicle to collect samples, of course. Both accuracy (how close our results get to the truth) and precision (how sure we are of the results) have improved in magnitude. You can now be certain of points, boundaries and areas. Data can be kept indefinitely and reused and recombined in new ways. Our only limits now are what we choose to do with the information. If you can think of it, we can do it. Faster, cheaper, better.
We look forward to hearing from you.