Ross Walters

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Everything posted by Ross Walters

  1. Unless you really know what you are doing, don't mess around with home built crop spraying drones. The combination of size and weight, and dangerous chemicals should be left to the pros.
  2. I have seen a lot of sugarcane ripening spraying done with the DJI Agras, some is very good, but some also very bad. Ripening of sugarcane is done by spraying a mild dilution of herbicide which scorches the plant and stops growth but does not kill it. this means that it is very easy to see how effective the spraying has been. If it was well sprayed then you can see a nice even browning of the crop, but when not done well it is very patchy and often stripy. I am not sure but I think RTK would help a great deal in improving the evenness of the application with the Agras.
  3. Ive been using NIR cameras on drones to generate NDVI imagery for farm management for about 8 years, and have done about 100 000 ha of NDVI mapping. The short answer is that I haven't found a really great platform yet at cost effective price. NDVI is also quite an art in of itself and needs a fairly good eye and understanding of the crop you are looking at. Most of the NDVI work I have done has been with a Sensefly Ebee with Canon S110 modified NIR camera. I don't particularly like the ebee platform and its let me down many times but I still keep just because it the camera that goes with it good and generates good results. I generally process with PIX4D and then work in Global Mapper to calculate the NDVI and adjust the shader to display the right colours for the and various values generated by the NDVI. remember that the NDVI is simply an NIR image that has undergone and algarythm which assigns each pixel a numeric value somewhere between -1 and 1, usually to 3-4 decimal places, that correlate back to photosynthetic activity. There are however many variables that effect the values, such light intensity, cloud cover, soil moisture, etc. This can to a certain extent be calibrated using calibration plates or light sensors integrated into the camera such as on the parrot sequoia, but I generally find it easier to simply adjust the colours and value ranges manually to suite the crop and conditions in the post processing. It's not very scientific, but i effectively calibrate the crop to itself and am able to highlight areas of good growth and areas of crop stress more clearly and in a way that will make sense the farmer. I have tried the Sentera on phantom and was hoping that it would be a good option to replace the ebee, but I was very unimpressed with the results. the values did not make any sense to me and I had to go through various different software programs to get a meaningful result that at the end of the day, I didn't actually trust. I also don't like the Parrot Sequoia, as the RGB side is really bad and the resolution on the NDVI is very poor. I have also heard that one of the online NDVI processing companies is sueing them because of the poor results they get from this camera. I think the Mica Sense camera is about the best off the shelf option for NDVI and generates some very good results, but it is very expensive at around $9-10 000. I have ordered an Xmission drone from Specialised Agricultural Services ( who are the XAG guys in South Africa, and will be testing it out as soon as it gets here and will let you know what the results are like. it looks very impressive as it comes with a similar type camera to the Micasense but works of a RTK base station, and you can use the imagery to plan and execute crop spraying operations with the XAG crop spraying drones. check out the video at
  4. Hi Felix I have some experience with crop spraying by helicopter, and also crop spraying drones, but not one like yours. I found that most of the crop spraying drones do a pretty crappy job with lots of patchiness, and are often more problematic than they are worth. The best crop spraying drone I have worked with is by for the XAG P series, its quite pricey but definitely the only one that truly delivers a uniform spray pattern, and lives up to its efficiency rates. I think the key is that it has RTK GPS, so it is able to keep its line very accurately, and can even do spot spraying on individual trees. I believe that there are over 30 000 of them in operation in China, where they are the go to platform for spraying. Also has nice and easy pilot controls. no RC skills necessary. check out and for more info on them The DJI is also okay and a bit cheaper, there are quite a few guys spraying with them in our area with some good and some not so good results. They do seem to have a few more issues for what I hear, and are not quite as durable. Let me know how you get on with yours. where are you based and what are you farming?