Forensic Mapping with 3Dsurvey
Our software can also be used for accident mapping in the field of forensics.
Introduction to Forensic Mapping
In this tutorial, we’ll demonstrate how to create a CAD sketch from photogrammetry data using 3Dsurvey. We’ll work with images captured by a Phantom 4 Pro in circle mode via the GS Pro app. This setup provides high-density point clouds ideal for forensic analysis.
Processing the Point Cloud and DSM
We begin by reviewing the point cloud and moving to create a digital surface model (DSM). Different view styles, such as exact Z-level positioning, allow for detailed surface inspection. The next step involves generating a high-resolution orthophoto, critical for accurate forensic CAD drawings.
Creating CAD Drawings in 3Dsurvey
In the CAD tab, users can establish layers for vectorization. Starting with the road, we select line thickness and color, then draw 3D lines with adjustable settings for 2D and 3D distances. This approach provides precise alignment akin to on-site surveying. For additional accuracy, users can refine line placement by rotating and zooming.
Finalizing the CAD Model
After completing the drawing process, we review the CAD lines within the point cloud and DSM layers, noting layer distinctions for objects like road markings and cars. Once finalized, we export the CAD model as a DXF file, suitable for use in third-party software like AutoCAD or MicroSurvey. The alignment of CAD lines with orthophotos ensures accuracy and clarity for forensic analysis.
Importing and Verifying in External CAD Software
In external CAD software, users can import the DXF file, visualize detailed layers, and add orthophoto underlays in the correct location, completing the forensic CAD workflow.