1. Description

Photogrammetry is a highly useful technique that enables the generation of 2D and 3D models from a dataset of geotagged images. This process involves analyzing images of a subject taken from various angles and distances to create a digital model of it.

2. Workflow

Step 1 - Open a site. 

Step 2 - From the "Analytics" tab, click on "Photogrammetry".

Step 3 - Click on "LAUNCH".

Step 4 - Consult and update the parameters if necessary. Parameters are detailed in the Paragraph 3.

Step 5 - Click on "LAUNCH MAPPING".

Step 6 - The Photogrammetry is launched. Click on "FINISH"

3. Information and Parameters

3.1 Processing estimations

Information about the number of images, processed pixels, and processing time.

3.2 My profile

By default, photogrammetry is set to the most common and widely used settings. However, it is important to note that these settings may not always be the most appropriate for your specific needs. Therefore, it is recommended that you take the time to review and adjust the settings to ensure the best possible results for your project

For a more detailed understanding of the photogrammetry engines and options, we recommend that you refer to paragraphs 5. and 6 of the article Photogrammetry Engines and Options.‍ 

3.3 Outputs generated

The output generated from the photogrammetry process will be defined by default based on the type of sensor used to capture the photos. (RGB, multispectral, thermal sensors). 

In the case of a multispectral camera, additional indices can be selected.

If needed, suffixes can be added to the outputs.

3.4 Photogrammetry CRS

The Platform suggests a CRS for photogrammetry outputs, but it can be changed to fit the project needs (refer to Coordinate Reference Systems (CRS)).

3.5 Reflectance Calibration

If calibration needs to be processed manually, click on "Manual radiometry of the calibration target".

Cases where manual reflectance calibration is necessary:

• Automated calibration failed during the first attempt (refer to Calibration Verification for Reflectance Map).‍ 
• The calibration target is an old model (ref <RP04 for Micasence).
• Following a recommendation from Alteia Support.

3.6 GCP

If you have placed and measured ground control points (GCPs) before the flight, click on the “USE GCP” and drag and drop your GCP file.

For more detailed information about uploading and tagging GCP files, please read the dedicated article here‍.

4. Results

The list of results is provided in the "Outputs generated" paragraph. Here are some examples:

• Orthomosaic

• DSM

• Point cloud

• 3D Model