The Analist Group Solution to carry out topographic surveys using the most innovative technologies: a DRONE and/or Telescopic Pole, Pix4Dmapper and Analist 2015 CLOUD
Do you really know how simple and factual it is to carry out a Topographic Survey with the latest technologies? Here you’ll find out how simple it really is!
In this article you’re going to find out how to perform the processing of topographic surveys and carry out all the typical topographic operations simply starting from photos shot with a DRONE and/or a Telescopic pole and obtaining point clouds, 3D georefrenced models and digital terrain models.
3 Fundamental Steps:
- Shoot a sequence of photos with a DRONE or with a Telescopic Pole;
- Transform the photos into a point cloud and a 3D georeferenced model with the Pix4Dmapper software;
- Import the point cloud into Analist 2015 CLOUD and carry out all the typical Topographic and Land Registry operations (profiles, sections, spot height plans, level curves and so on).
1. Shoot a sequence of photos with a DRONE and/or a Telescopic Pole
The first thing to do is take a sequence of photos using a DRONE and/or a Telescopic Pole. The shooting techniques are those typical of photogrammetry and terrain digital models.
The procedure is called “nadir” or better the fotocamera facing the ground with the UAV flying along an “s” trajectory in order to achieve overlapping frames.
In Pic.1 the Nadir flight is shown. From an operative point of view the sequence of photos was started as soon as the UAV started flying and shooting. The camera is facing down (90° flight plan). In Pic.2 you can see the button to push to tilt the camera.
Pic.2 – Camera Nadir Setting
In the panel on the right you’ll find the icon to set the automatic shooting every three seconds. Remember to activate the shooting sequence only when the UAV has reached the expected altitude. If the shooting starts during take off, photos of the initial phase will be added, these are not useful for the photogrammetric reconstruction.
In Pic.3 you can see the flight sequence in detail. It is important to set the speed of the UAV at the the lowest range possible.
If you set a route with the DJI -Vision programme for iPhone or Android (Pic.4) the key which adjusts speed is the one at the centre of the screen and has three modes: Slow, Mid, Fast. For photogrammetric shooting the correct setting is Slow.
Analist Group uses the DRONE DJI Phantom 2 Vision Plus.
When the use of a DRONE isn’t possible you can use a Telescopic Pole:
NB: Analist Group is official partner to DJI and Neutech.
2. Transform the photos into a point cloud and a 3D georeferenced model with the Pix4Dmapper
The next step is to import your photos into the Pix4Dmapper Software which will automatically generate the point cloud, the Ortophoto, the land digital model.
The operative sequence consists of three simple steps:
1-Project creation
2-Selection of photos to be processed
3-Start the processing: START
Obviously, for topographic surveys the project georeferencing is necessary. The georeferencing procedure implies that the coordinates of at least three points on the ground must be known (5 would be even better) and that the known points can be observed in the photos taken during the flight.
The coordinates can be obtained with more traditional topographic methods like total stations or GPS. In operations where a model in a 1:1 scale is required a distance acquired with a metre or a laser metre (Disto) is enough. For example, you can take a sequence of shots along a road or a canal to measure the excavation volume of an accumulation of carryover by simply walking with a 5 metre telescopic pole which has a GoPro fixed on the top; in this case the measurement of a known distance is enough to carry out the volume calculation extremely rapidly and with great precsion.
Watch the Pix4D software in action:
Pix4Dmapper includes the most common and widespread camera profiles and lenses and supports photos with geotag and GCP to obtain a perfectly georeferenced 3D model.
Analist Group is a Pix4D Official Partner
3. Import the point cloud into Analist 2015 CLOUD and carry out all typical Topography and Land Registry operations
After generating the point cloud with the Pix4Dmapper all you have to do is import it into Analist 2015 CLOUD, Topography and Land Registry Software based on the Autodesk technology, and carry out all your topographic operations (profiles, cross sections, level curves, spot height plans and so on).
Watch the Analist 2015 CLOUD software in action:
You can also watch case studies of topographic surveys as well as archtectural surveys which we have developed with Analist 2015 CLOUD, Pix4Dmapper and the DRONE.
Watch videos of the events in which we have presented our Innovative Solution for Topographic Surveys with the DRONE, a telescopic pole, Pix4Dmapper and Analist 2015 CLOUD.
