We are anticipating to use PIX4D Field quite a bit this year on our experiments. One of them will be a Canola Photosynthesis trial. Here we will collect data on 180 genotypes of canola. The first bunch of data will be canopy cover. We want to know which lines will close the ground faster. For canopy cover, which index to do you think will be recommended (NDVI?). Is there some literature about this that I can follow?
For your Canola Photosynthesis trial, NDVI (Normalized Difference Vegetation Index) is indeed a suitable index to measure canopy cover. NDVI is widely used to assess plant vigor, biomass, and canopy cover, as it takes into account the difference between near-infrared (NIR) and red light reflectance from the plant canopy.
To calculate NDVI, you can use the following formula:
NDVI = (NIR - Red) / (NIR + Red)
In your case, you can use PIX4Dfields to create NDVI maps based on the multispectral data you collect from your drone flights. By comparing NDVI values across different genotypes, you can determine which lines close the ground faster and better understand their growth patterns. For that use the annotation tools, to draw your plots, that will allow you to get plot average index data you can use for ranking the different varieties.
Here is a source for further reading:
Thank you Julius,
You are a great man. I am new to this type of data collection. we are expecting to have our Mavic 3 multispectral within the next 3 weeks. Once I get the first flights I might need to contact you again.
Thanks again for your feedback.
We are happy to help, we love that stuff as much as you do :). Here is a video which should give you an idea how to use the annotation tools in PIX4Dfields to get your plot level data (at minute 5:30):
You demonstrate importing geometry shape files, but where are these obtained from? Geometry files for what?
You either get them from you client or you created them in a GIS system like QGIS or Google Earth, we support .kml ; shapefile and .geojson.
Thanks. I tried Google Earth and exported a boundary, but get this error message when importing the kml file. Is that expected?
Make sure the boundary does not contain any error when drawing it (complicated edges).
Try creating a simple geometry and importing it in PIX4Dfields. If it fails, please share the file with us so we have a look.
Can PIX4D generate Leaf Area Index?
We have 4 reps of Lime trials. Each rep is in a different place of the farm field, very far away from each other. I have the 4 corners GPS coordinates of each rep, but do not know how to create a shape file so that the drone can flight only on each rep, not the entire field. Also making the shape file it will be ease for us to extract the data from each rep.
How easy it will be to transfer your GPS coordinates to Pix4dfields, depends in what format you have them. If they are already as shapefile, kml or geojson you could import them as annotations, and manually create the field boundaries on top of them.
If not you need to convert them via Qgis to one of the formats I mentioned above.
All in all should be a swift process.
Do you have a walk through to convert the 4 corners of a research plots field to a shape file using QGIS?
Without knowing the format and structure of your GPS data this question cannot be answered.
I have the gps coordinates of the 4 corners of each rep. For now on google earth I am dropping a pin on each coordinate, then I draw a rectangle following those pins. After that I delete the pins and save the file as a kmz.
I thought there must be a better way to do this.
If you export it as kml from Google you can import that into Pix4Dfields as annotation or boundary.
If you want to create the plots automatically from the GPS data, this is a different story but can be done in QGIS.
To really help you we would need an example file from you.
This PIX4D definitely needs some improvements. It is too tedious to draw the boundaries of each plot manually. It also sometimes it fails to save the boundary, as you can see, it check mark is grayed even though the polygon has been closed. Other software such as Solvi will identify each plot automatically provided each plot is clearly separated from one another.
Attached is the screenshot.
Yes we are aware that for big plot trials the current annotation tools are limited and a bit time consuming. We will eventually revisit this topic in the future, but this will not be soon to be honest with you, as our focus is currently on improving the software for practical applications in Agriculture.
For research a great tool alongside PIX4Dfields is QGIS which is actually completely free. Here is a tutorial on how to do what you want to achive: How to separate plots and extract plot data using QGIS (Drones in agriculture series, 5/7)
Thank you so much Julius for the quick response.