Tips For Drone Weed Surveys In Agriculture.

The use of drones in agricultural settings is a perfect application for the technology. Open pasture or monocultures make the task of identification simple and facilitate the reliable use of auto detection and classification methods. This means that weed maps can be generated very cheaply. The use of drones is already delivered at a significantly lower operational cost when compared with the classical manned aerial photogrammetry.

Detailed weed maps can be a useful information tool for your property. By measuring extent, distribution and abundances of different weed species, drone based weed maps can inform control activities and track the expansion or retraction of populations over time.

To make use of information regarding the extent and distribution of weeds on your property, it is important to capture imagery at key times in the life cycle of weeds.  Drone are operationally more flexible than manned aerial photographers, deploying quickly, around your schedule, with no disturbance to livestock and worrying little about cloud.

The identification process does have limitations. When supported by ground truthing activities, confidence in identifications can improve, but examples of lookalike species with similar growth habit and spectral reflectance signatures do occur.

Here are some useful tips on how to reduce the occurrence of misidentifications and improve your weed surveys/maps on your property when employing drones.

1.  Know your objective.

Drones can also capture important information regarding the health of crops, however different sensors are required for this. Two birds can be got with one stone if the operator clearly understands what data you are trying to capture and will plan missions accordingly.

2.  Get a qualified and experienced professional to review the data.

Having a professional who understands and has experience with the assemblage on your property will help improve confidence in the identification process. They should have the knowledge of the seasonal colour changes, flouring systems, growth habits and other ecological parameters essential in distinguishing between weeds.

3.  Conduct thorough ground truthing activities.

Ground truthing will verify the spectral signature of individual species. A quick way to do this is to take geolocated images of the dominant and target weed species. This will ensure you have the location of know plant to refer against the weed map. Make sure you have multiple samples of each species to ensure you have a representative sample.

4.  Capture at appropriate resolutions

Make sure you are capturing your data at a resolution that meets the needs of the objective. Understand that the generation of orthomosaics can often reduce the end output resolution. You may need to compensate for this. Capturing test images at a range of altitudes can assist in finding the minimum resolution threshold for your application.

5.  Choose your season of survey

Flowering and seasonal growth cycles can be very useful in identifying plants. Choosing a time of year when your target species or their lookalikes are in flower or losing its leaves is an easy way of improving the confidence in your vegetation maps.  Use the ecology of the plants to your advantage. This may not always be possible as synchronising project, weather and ecological cycles can be difficult.