Lab #4: Processing Data in Pix4D No GCPs

Introduction

In this project we did data processing for the data from the Wolfcreek UAS mission. We used a software called Pix4D, a software that implements data processing and photogrammetry. We used the data from the Wolfcreek flight to create a 3D orthomosaic and a digital surface model (DSM). We then used this raster data to create professional maps just like in Lab #3.

Figure #1: Ortho and DSM 

Figure #2: DSM Comparison

Methods

We launched the Pix4D software and created a new project. This will be named by the flights metadata. We then added all the photos to the application from the Wolfcreek flight. We then proceed to use the 3D maps function to create our orthomosaic and DSM for the data. We ran the data processing on the intial processing and uncheck boxes 2 and 3 to check for any problems with the data. After we check the quality report for the initial data we can move onto the other data. The data looked good so I proceeded to uncheck box 1 and process boxes 2 and 3 which are the Point Cloud and Mesh and the DSM Orthomosaic Index. We also check the quality report for the full processing, if that looks good and there is very few rejected pictures we can move on. After everything was processed I went ahead and created an animation of the map after fine tuning it and meshing it.

The raster data we gathered for the orthomosaic and the DSM can then be put into ArcGIS, these maps will look slightly different than the maps in Lab #3 because we did not put the GCPs data into Pix4D. you can tell the difference between the maps when you look at the elevation values of the maps.

Figure #3: Pix4D Wolfcreek Animation

Results and Discussion

Pix4D processed and placed data in folders we setup to be organized. Pix4D will put the quality report and initial data in separate folders. The overlap lets us see which pictures overlapped and where. The quality check shows that everything went well while processing the data and if geo referencing was used or not. The summary shows how long it took to process the data, area covered, camera used, ground sampling distance (GSD), date processed, and the name of the project.

Some points could not be identified like side walls due to the top down photo style. Some data processing failures could be due to bad images or unidentified points in the data. Flat untextered areas and forest debris can confuse the software and be removed or look unproportionate.

Figure #4: Quality Check Overlap

Figure #5: Quality Check

 

Figure #6: Summary

Conclusion

 Pix4D is a great application for UAS because it allows you to process a lot of images or data in a relatively short amount of time. It helps keep your data organized and easy to digest for others viewing your projects. It is a perfect softare to paire with ArcGIS Pro because it allows you to take the data you processed straight from Pix4D to ArcGIS Pro, allowing you to create your detailed maps such as the orthomosaic and the DSM. The software was hard to understand at first, but is very helpful on guiding and teaching you how to use it effectively.