Creating a Mapping Mission

Unmanned Aerial Vehicles (UAVs) can create orthomosaics to better understand ecosystems. To plan the flight path of a UAV for orthomosaic creation, we’ve developed a plugin compatible with QGIS

UAV Mapping Path Generator (for Litchi)

Our UAV Mapping Path Generator plugin takes into account camera parameters, altitude, overlaps, and more to prepare an optimized flight plan. This flight plan is compatible with the FlyLitchi app, which operates flights for DJI drones.

The steps below describe the installation process, logic and method to use the plugin. To install the plugin:

1. Go to Plugins > Manage and Install Plugins.

2. Search for UAV Mapping Path Generator (for Litchi) and install it.

Fig. 01a: Install the plugin.

Fig. 01b: Install the plugin.

The plugin will be available for use from the ‘Vector’ menu.

Fig. 02: UAV Path Generator Plugin. 

SETTING UP THE PLUGIN

Some default drone camera specifications are pre-filled in the plugin. However, you can adjust these settings by accessing the drone specifications for your specific model here.

Mandatory Inputs for the Plugin:

• Altitude

• Field of View (FoV)

• Side Overlap %

• Front Overlap %

• Aspect Ratio

• Image Height & Width

• Speed

• Gimbal Pitch Angle

These drone camera parameters are readily available in the drone specifications. The overlap percentages you choose will influence both the area covered and the time taken for the drone to complete the flight. The plugin calculates and displays the approximate flight time at the end of its execution (see Fig. 05).

Note: The flight time shown in FLyLitchi is slightly longer than that calculated here.

The parameters and the input types are as described below.

Fig. 03

Fig. 04: Calculated parameters and formulae.

How to use the PlugIn:

Then the user has to upload a shapefile of the area of interest. This shapefile should be of polygon geometry type only and in EPSG:4326 GCS projection. The users are advised to select a polygon and fill this input in every execution and make sure to click on the ‘Load’ option after filling the input. Following the selection of AOI, the user must draw a line - ‘Input_line.shp’:

Notes on the line:

• This line must be outside the AOI polygon.

• It should be in a direction parallel to the desired drone path.

• The drone path will be drawn to the right/above this line.

• This line is plotted in EPSG:4326 GCS projection.

As soon as you click on the ‘Draw Line’ option, the toggle editing is enabled and the user will be prompted to draw a line in the required direction. To end this action, save the edit, untoggle the edit mode and then the plugin dialog box will pop back in the map interface and the draw line box will be populated.

Then the user should input an approximate number of parallel lines to the input line that would cover the entire area of interest. When the user clicks on the ‘Draw Flight Path’ option, the parallel lines are drawn and clipped to the area of interest and then the way points are created according to the overlap percentages as shown in Fig. 06.

The flight time is also calculated as soon as one clicks on the ‘Draw Flight Path’ is clicked. The Fig. 05 shows that the flight will take 60 minutes to finish the entire flight. Hence, the user must split the area to be covered in each flight as one drone battery gives 20 mins of effective flight time.

Fig. 05: Flight time calculated.

Example of input line and the drone path:

(a) Input horizontal line, (b) Drone path with horizontal input line at the bottom,

(c) Input vertical line; (d) Drone path with vertical input line on the left.

Fig. 06: Input for a drone-path.

Fig. 07: The flight path in FMH.

A Fly Litchi compatible csv file is then created and it can be opened in Fly Litchi Mission hub.  Make sure the waypoints in the csv file show on the map view.

From this point, one can use the FlyLitchi App to check settings and execute the mapping mission. For more instructions on using the fly litchi app, please refer to our other blog on planning photo and video missions for UAVs.

Below is a visual walk-through of using the above plugin.

Here Comes the Drone

Field notes from Bihar, 2023.

As the sun set after another day of fieldwork, we returned to our accommodations. I recounted the day's events while transferring media. We spent the morning in the field, followed by a quick lunch, and then returned to the field. Later in the evening, we prepared for an upcoming workshop with the forest department. Our days in sunny Bihar this February had been exciting.

Our day was indeed full of action, conducting aerial transects to estimate gharials at our field sites along the riverbanks of the Gandak. We scanned the waters intently, hoping to catch a glimpse of life beneath the surface. The splashes and movements in the water kept us on edge, wondering if it was a dolphin or something else entirely. Moving to another site on the north bank, we got started on our drone transects, and that's when things took an unexpected turn – a buffalo nearly charged us! The adrenaline rush was real, but we pushed through, even laughing, completing our tasks and moving on to another location to observe dolphins. During our time on this site, we counted four gharials and a solitary dolphin, while also spotting an enigmatic stork.

Evading a curious buffalo on field-site.

After wrapping up our fieldwork, we returned to charge our drones and have a quick lunch. Our tasks for the day weren't done yet – we were headed to another site near our accommodations for mapping and conducting bathymetry tests soon after. Bathymetry tests involve measuring the depth of water bodies, in this case, of the river. By initiating the flying of the drones over the same river channel, our objective was to ascertain whether RGB drones could provide any information regarding the river’s bathymetry.

Once the media we had gathered were transferred, we set off for our next site. Though the plan didn't unfold exactly as anticipated, the unexpected offered new opportunities. The survey boat was unable to go around the sandbar as intended. Instead, we flew the drone following the boat's path to take pictures at frequent intervals along the same route. This was a way to conduct simultaneous surveys using two different techniques: not only exploring the presence of dolphins but also comparing methods used.

Survey boat as seen from the aerial drone.

The integration of drone technology has repeatedly demonstrated its potential in conservation efforts. Drones' capabilities to swiftly and comprehensively survey areas can reshape how researchers and conservationists approach their work. High-resolution imagery captured by drones works to bridge the gap between traditional survey methods and modern technology, enhancing data accuracy and efficiency. For those of us fortunate enough to witness the impact of drones on conservation firsthand, tangible feelings of excitement and curiosity emerge.

It was during this flight that the true excitement around drones became evident. As the drone took to the sky, a group of children gathered around, captivated by the spectacle. Their excitement was contagious, as they curiously identified the drone and spun imaginative stories about its purpose, whilst mistaking my hand-held camera for a CCTV! In a sense these robotic ‘toys’ facilitated a more accessible dialogue about wildlife.

Children taking turns viewing from a pair of binoculars, whilst the project team conducts a mapping mission from the banks of the river.

The stunning illustrations of local wildlife prepared by the GCA and Madras Crocodile Bank shared by Tarun Nair as part of his presentation to the forest department.

The evening was one of light chatter and marvelling at the rich diversity of this region. A glimpse of the stunning illustrations of local wildlife, compiled by Tarun Nair as part of his presentation to the forest department, served as a reminder of the beauty we were working to protect.

The excitement and curiosity surrounding drone technology for conservation are undeniable. With each passing day, more researchers and conservationists turn to drones, gaining insights into our natural world. Being a part of this field is a privilege, and I'm excited about the future and the positive impact drones can have on conservation.

My First Job: Lessons, Skills, and Memories with TfW

I think everybody very prominently remembers their first job and the experiences that came with it. Similarly, my journey started after I spent the end months of 2021 looking for opportunities, after completing my Master’s education. It was a phase of uncertainty and at times, I did feel anxious. I applied to Technology for Wildlife Foundation but didn’t get selected in the first go. However, I remember I appreciated the hiring process at TfW- mostly because the interaction with the team during interviews was quite warm, and I was happy with my performance in the test they held. I wrote back to Shashank, genuinely appreciating the process, even though I missed the chance to work with them. At the back of my mind, I still looked forward to working with them in the future.

Flying a drone with the team.

Fast-forward to May 2022, in the middle of my ongoing internship, I received an email saying they had a vacancy for the post of Conservation Geographer at TfW and were interested in taking me on board. That email felt like a manifestation (not an exaggeration). I remember jumping with joy and finding it hard to believe. 

Aditi holding her first-ever business cards.

Starting my first job was filled with feelings of excitement and nervousness. It brought with it many changes-; like moving to Goa- a place I had never even visited beforehand, with many firsts- like seeing the sea for the first time, flying kites, trying football and conquering the fear of water. I was worried about fitting in, understanding the office culture, and getting to know my new colleagues. I had heard stories of people not liking their job experiences and somewhat had the impression that maybe that’s how it worked. But maybe hard work and luck worked for me. I met some of the best people there and now have a beautiful experience to share.

Experiencing sunset at the Arabian Sea, another first.

Before joining, my role in the organisation was explained to me. My position was of a Conservation Geographer and I remember during my interview, Shashank asked me “Do you want to do GIS because you like GIS or would you do conservation that has GIS in it?” I chose the second option and got to practise what I was promised.

Learning to use a Remotely Operated Vehicle (ROV).

I got to work with many different organisations, and create maps that lead to tangible changes. Creating maps for Mongabay-India’s conservation stories was one of my longest running commitments in the organisation. The arrival of each story was exciting because of the process- of trying out methods and deciding what kind of map would best depict the conservation story. I remember I felt quite challenged when I got my third mapping task for Mongabay-India which required me to create port boundaries from descriptions. At first, it felt like riddles, but in the end, it was one of my most impactful maps and I am proud of it.

In the beginning, because I was new and developing skills, I was anxious to complete the task that I was given and ended up working long hours. Shashank, who I was reporting to, checked on me because working longer hours or on weekends is highly discouraged at TfW.  I was taught to have a work-life balance and to focus on myself along with the job. One of the most valuable aspects of this experience was the relationships that I formed. This job introduced me to wonderful people- my colleagues who were also mentors, as well as others working in the field of conservation. 

Climbing trees on a field trip.

I wouldn’t have ever imagined all these possibilities without this platform, a vision that Shashank brought to life. This was made more unique because of the team- mostly women- working together through thick and thin. Even though our work is technological, there was nothing robotic about the team. It was built as a safe space filled with warmth, learning, and encouragement to do amazing work. Even though I now bid adieu to this organisation, I will be forever grateful to the team, for the experience I got here and for setting my standard so high.

Play-testing a board game with the TfW team.