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Mappt & QGIS Workflow: Using Drones to Enrich Field Assessments

DEM Dubai Airport Satellite Imagery Digital Surface Map orthomosaic sentinel 2 multispectral bands satellite imaging corporation

When it comes to fieldwork, the best outcome (aside from zero injuries) is to return having collected as much high-quality data as possible. We all want to ensure our project goals are reached successfully, so using a wide variety of relevant data to address the project criteria is a good strategy. An example of this is producing high resolution Digital Surface Maps (DSMs) using drones to complement field surveys conducted on-foot. These DSMs can provide additional information such as elevation, NDVI indices and more to complement the field survey data. 

DEM Dubai Airport Satellite Imagery Digital Surface Map orthomosaic sentinel 2 multispectral bands satellite imaging corporation

Digital Surface Map of Dubai International Airport by Sat Imaging Corp.

The workflow below describes the process for creating a DSM with QGIS to produce a data-rich field map, which complements field survey operations conducted using Mappt.

The Mappt team conducted a field survey at Kensington Bushland, in which we collected a range of points to characterise the local vegetation using Mappt.

Kensington Bushland, City of Victoria Park, walk leisure recreation natural park for

Kensington Bushland, City of Victoria Park

Each survey point contained a range of attributes for the field worker to fill out on location, including plant species, condition, time, % coverage etc. We created the attribute form using Mappt’s handy drop-down feature to collect all the field data. This was of course put together and pre-loaded prior to heading out into the field, like the intelligent and efficient field workers we are 🙂

(Click HERE for a free copy of our Ultimate Field Checklist)

Of most interest for this assessment was the species and condition of vegetation at the field site. The project goal was to explore trends that may explain any gradients in the species structure, coverage and/or condition. We collected additional drone imagery over the survey area, which was used to provide valuable complementary information on the vegetation community.

 

Now that we’ve returned from the field in good spirits and relatively unscathed, it’s time to begin our workflow process for the field survey!

Loading Mappt data into QGIS

First, we want to export the survey data collected using Mappt and bring it into QGIS. To do this, we want to navigate to the saved project file within Mappt and then click the export icon. We then want to select all layers, choose the GeoJSON format for QGIS, then choose to export to external apps, lastly selecting Google Drive as the export location. (See below)

Mappt user interface field mapping collecting georeferenced images for vegetation assessment screenshot_20190605-110141

That’s it, put down the tablets people! You’ve successfully collected and exported your field data from Mappt. Pretty easy right?

Now we want to move over to our desktop computer and load the Mappt data in for further processing in QGIS. Open up a new project in QGIS and check that the CRS projection is set to WGS 84 (under Project > Properties).

Next, add Google Satellite as a base layer for your project (click on the Web > QuickMapServices > Search QMS, then click on Google Satellite in the window that opens in the bottom-right).

 data-source-manager-icon

Click this icon to Import the Mappt data from Google Drive into QGIS through the Data Source Manager.

 

 

Now double-click on the Vector file in the Layer Window to make any style changes desired. For my data, I have characterised survey points into species type and given them different colours. I also filled in the polygon for the reserve area, and indicated my survey entry and exit points with coloured lines.

mapptdata

Now you’ve got your Mappt survey data looking schmick in QGIS, it’s time to bring in the drone images to create a DSM overlay! First, we will need to combine all the photos from your drone together into the one orthomosaic (to rule them all).

Creating a Digital Surface Map using Drone Deploy

Go to http://dronedeploy.com and create an account if this is your first time using it. Then simply upload all your images into the window and drone deploy will create an orthomosaic for you! You can change the processing time by toggling the speed vs quality bar under the ‘Advanced’ tab. Click ‘Upload Images’ to begin the process.

It might be time for a tea break now, as this does take a while.

drone deploy mapping software online orthomosaic creator drone imagery

Once the map has finished processing, you have the option to export the orthomosaic as a natural colour GeoTIFF, as well as NDVI index and Elevation map. Export any that you want and ensure they are GeoTIFFs.

Now, we want to bring QGIS back up and load in the files, once again using the Data Source Manager.

raster-icon Click this icon within Data Source Manager to load the GeoTIFFs as raster files.

Again, we can change the opacity and style of each layer to get the desired style. For my orthomosaic, I chose to reduce the opacity of the natural colour layer so that the elevation can be seen.

orthomosaic-data

There are some interesting features of the elevation that seem to overlap with some patterns in the vegetation structure! We should create a map to show the boss.

Creating a map in QGIS including Mappt survey data and DSM data

print-layout-icon To do this, we want to click on the Print Layout icon in QGIS.

This opens a blank page from which we can begin to draw our map.

addmap-iconIn the Composition Window that’s just opened, click the ‘Add Map’ icon.

Then click and drag an area over the canvas in the window to produce a map. The map produced is based on the view in your main QGIS window, so you may need to do some final style tweaks to finalise the image.

map-icons You can then add a Title, Legend and Scale bar to your map using their respective icons.

You can customise all of these to your liking by clicking on the feature then using the ‘Item Properties’ window on the right to adjust the information displayed.

imageicon Next, add a North Arrow by first clicking on the ‘Add Image’ icon.

Then, navigate over to the ‘Item Properties’ window and click on the ‘Search Directories’ drop down. Here you will find a number of images that are suitable as a North Arrow.

Lastly, click on the map itself and navigate through the item properties until you find the ‘Grids’ drop down (See below). Click on the green plus icon to add a grid, then click Modify Grid to set the scale. Once your grid is displayed nicely, lastly change the frame style to ‘Zebra’ and then close out.

grid

Voila! Your map is now complete for reporting. For my data I’ve found a pattern between increasing elevation on my DSM, and abundance of Banksia menziesii. Neat!

QGIS map of kensington bushland created using mappt and drones to produce digital surface map and vegetation survey data

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Help is on its way!

Mappt has been on the market for a little while now and is being used by more people every day. Its features are growing almost as fast as its users, and to keep up with this demand, we’ve started to expand our support for Mappt.

We’re creating new tutorials, tips and tricks, and building users’ suggestions into Mappt. One of the most popular requests was a new help system, which is being built into the next update of Mappt, along with some other little goodies. Very soon you’ll be able access these features from almost anywhere in Mappt, so help is always at hand – well, fingertips actually.

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