GCPs for drone mapping

Placing GCPs with Reach RS+, Lone Drone Services, Canada, Ontario

What GCP is and how it works

Placing Ground Control Points

Reach provides accurate coordinates for GCP
You get repeatable mapping data

Our customer KiteMap from Colombia flew over a site multiple times at different altitudes with DJI Phantom 4 Pro. They processed orthophoto and DEM and extracted contour lines.

Contour lines
processed
without GCPs

Processing software relies only on the drone's GPS data recorded in its photos' EXIF. Therefore, the accuracy of the final orthophoto is only meter-level, so contour lines don't match.

Contour lines
processed
with GCPs

Drone images are georeferenced with GCPs. The final orthophotos are accurate so the contour lines are almost identical and have the same shape.

Drone Pilots using Reach

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Development of an avalanche monitoring system

Thor Veen, CSO, Aeria, Canada

Aeria team used Reach RS2 units to place ground control points. This data helped the team to develop an avalanche monitoring system in the north of Pemberton, British Columbia.

Mapping the extent of invasive seagrass

Corbin Kling, North Carolina State University, USA

Researchers from North Carolina State University placed GCPs with Reach RS+ for mapping the extent of invasive seagrass. The project was aimed at developing innovative options for habitat restoration and resistance to harmful invasive seagrass.

3D modeling of an irrigation system

СampoDigital, Chile

With the help of Reach RS2, the СampoDigital team placed ground control points for the drone flight in Osorno, a famous center of agriculture and cattle farming in Chile. Then, based on the collected data, they made a 3D model of the area for the irrigation project.

Drone mapping of gully erosion

Mangoesmapping, Australia

The Mangoesmapping team used Reach RS+ to place GCPs for a drone mapping of gully erosion. The project was to evaluate the effectiveness of erosion minimization methods and reduce the negative impact on water quality on the Great Barrier Reef.

Land surveying

Krops, Chile

With Reach RS+ surveyors from the Krops aerial services company placed GCPs for the land surveying project at Ranco lake in southern Chile. The project was to divide the 20 ha field into small pieces of land and build several cottages.

Estimation of crop density

Joshua Koh, Agriculture Victoria Research, Australia

Research scientists from Australia developed a method to estimate crop plant density using UAV imagery. They utilized Reach RS+ to place ground control points with sub-centimeter accuracy. The resulting map summarized the number of safflower seedlings. The model can be used to estimate the plant density of different crop types.

Evaluating repeatable data precision

Christian Grüner, CEO, Dronographica, Denmark

The researcher from Dronographica experimented with evaluating the relative repeatable precision of the Reach RS+. He measured GCPs with Reach RS+ and got sub-cm precise data for photogrammetry.

How Reach receivers work

Reach is an RTK receiver. RTK is a technique used to improve the accuracy of a GPS receiver. Traditional GPS receivers could only determine the position with 2–4 meters accuracy. RTK can give you 1–2 centimeter accuracy.

You don’t necessarily need a second unit for RTK all the time. Usually, there are local services that share base corrections over the Internet. This technology is called NTRIP.

How to get started

Explore the site and place ground control points

Determine all features of the landscape and analyze the amount of GCPs — in most cases, from five to ten points are required.

Connect your rover to a local base or NTRIP provider

Using the ReachView 3 app, create a survey project and choose your local coordinate system.

Collect the coordinates of each GCP with the rover

The Reach receiver allows you to get centimeter-precise data.

Fly a drone

Fly an area to collect aerial images with any drone such as Phantom, Mavic, etc.

Export GCP from Reach in CSV format

Once data is collected, you can export your project in CSV, DXF, GeoJSON, DroneDeploy CSV, or ESRI Shapefiles format.

Import photos and GCP list to mapping software

Upload CSV file with GCPs to your mapping software for accurate georeferencing. Create your project with DroneDeploy, Pix4d, Agisoft, or other mapping software.

Surveying
with ReachView 3

Collect points

Create a survey project and collect data in your local coordinate system.

Coordinate systems based on

WGS84, NAD83, GDA2020, and others

Export GCP list to CSV

Record each position as a point with centimeter precise coordinates. You can export your survey project in CSV which is recognized by most mapping software.

Engineered to be tough
Reach receivers are designed to work in challenging conditions, even dusty areas, under the burning sun, and in frosty areas

-20…
+65ºС

Working temperature. Isn’t afraid of either heat or cold.

IP67

Can be held 1 meter deep underwater for half an hour.

Up to
22 hours

Industrial LiFePO4 battery that doesn’t die of cold. Can charge over USB from a powerbank.

Choosing the set of RTK receivers
Depending on the working area

User reviews

Mapping Iceland Glaciers

Jurijs Ješkins, the researcher at the faculty of Geography and Earth Sciences, University of Latvia

We used two Emlid Reach RS, one as a base and the other as a rover, and were surprised by the good performance and long battery life in very windy, wet, and cold conditions.

Intertidal Oyster Reef Mapping with Reach RS

Anna Windle, Ph.D. Student, Horn Point Laboratory, University of Maryland Center for Environmental Science, USA

The Emlid receiver has proved to be an efficient means of surveying out in the field. A hotspot was used to connect the receiver via Wifi and GPS data was easily collected with a smartphone through the Emlid surveying application page.

Volume Measurement with DJI Phantom 4 and Reach RS+

Isaac Vazquez Flores, Mining Engineer at Dromine, Mexico

Reach RS+ allowed us to quickly collect GCPs before drone mapping with Phantom 4 and helped to carry out precise volume measurements of the feldspar stock. The results obtained with a drone are identical to one obtained with a total station.