FOSS4G 2024 Workshop

Introduction:
This workshop presents the importance of FOSS tools such as WebODM and QGIS for drone image processing. We will cover the pre-processing of control point photographs in QGIS using the LFTools plugin, followed by the post-processing of photogrammetric products (orthophotos, elevation models, and point clouds) generated by WebODM. Additionally, some applications with the CloudCompare software will be discussed.

QGIS and the LFTools Plugin:
QGIS is an open-source Geographic Information System (GIS) that enables the visualization, editing, and analysis of geospatial data. Known for its flexibility and robustness, QGIS supports a wide variety of raster and vector data formats and integrates with other GIS software. One of its main advantages is the ability to expand its functionalities through plugins.
QGIS plugins, developed by the global community, allow users to add new tools and features such as advanced geoprocessing, field data collection, spatial analysis, image processing, and 3D visualization. Notable examples include the LFTools plugin for drone photo processing and the GRASS plugin for advanced geospatial analysis. This extensibility makes QGIS a versatile and powerful tool for professionals in various fields who need geospatial solutions.

OpenDroneMap / WebODM:
OpenDroneMap (ODM) is an open-source software for processing drone images. It transforms aerial photos into orthophotos, digital terrain models (DTM), digital surface models (DSM), and 3D point clouds. ODM is widely used in mapping and cartography applications, offering an accessible and customizable alternative to proprietary software. The open-source community supporting ODM ensures continuous updates and the inclusion of new features.
WebODM is the web interface for OpenDroneMap, designed to facilitate access and use of ODM through a browser. It provides a user-friendly interface for uploading, processing, and viewing drone images. With WebODM, users can manage mapping projects, visualize results, and perform analyses directly on the platform, making the drone image processing workflow more accessible and efficient. The web interface allows for collaboration and data sharing, increasing productivity and accessibility of drone image processing tools.

CloudCompare:
CloudCompare is an open-source software specialized in the visualization and processing of 3D point clouds. It allows users to visualize, edit, analyze, and compare point clouds and 3D mesh models, performing tasks such as filtering, segmentation, data registration, and volume and distance calculation. Initially developed for comparing high-density point clouds, CloudCompare is widely used in various fields, including geography, engineering, and archaeology. Its active community ensures continuous improvements and support, keeping the software updated and relevant to user needs.

Workshop Content:
1. Brief Introduction to Drone Image Processing:
 - Importance and applications in cartography.
2. Loading and Selecting Photos in QGIS by Location:
 - Techniques for image selection and organization.
3. Filtering by Date and Time with the "gpsdate" Function:
 - Using metadata to filter images.
4. Separating Processing Blocks:
 - Strategies for dividing large datasets.
5. Photo Histogram Adjustment:
 - Improving image quality for processing.
6. Processing in WebODM/OpenDroneMap:
 - Steps to process drone images using WebODM.
7. Why Use Alpha Band?
 - Advantages and disadvantages of using the alpha band in images.
8. Photometric and JPEG Compression:
 - Compression techniques for efficient storage and processing.
9. Efficiency of TIFF Pyramids with Compression:
 - Benefits and techniques of using TIFF format with pyramids.
10. ECW vs. TIFF Comparison:
 - Comparison between different image formats.
11. Generating Point Clouds with DSM and Orthophoto:
 - Production and use of point clouds and orthophotos.
12. Adding Value to Drone Mapping:
 - Strategies to increase the utility and accuracy of drone mapping.

Requirements:
As the workshop is only 2 hours long, participants should bring their notebooks with QGIS, LFTools, WebODM, and CloudCompare installed.

Who Should Attend This Workshop:
This workshop is intended for professionals and students in the fields of geotechnology, cartography, geography, engineering, surveying, architecture, urban and environmental planning, among others. It is especially useful for those who use drones for mapping and need to ensure the precision and quality of the collected data. Additionally, it is ideal for anyone interested in learning how to use open-source tools for drone image processing, such as QGIS, LFTools, WebODM, and CloudCompare, and who seeks to enhance their skills in geospatial data manipulation and analysis.