Photogrammetry and Ortho Mapping

Photogrammetry is one of the major industries in the remote sensing field. What used to take very expensive software and highly skilled photogrammetrists can now be performed using software tools in ArcGIS Pro for aerial and UAV imagery to produce color balanced image mosaics, digital surface and elevation models for use as base data or to derive other products such as hillshades, slopes, and contours.

If I were a photogrammetrist, I would still use tailor made software that can handle huge quantities of imagery and very high-end computing technology to crunch the data.

This set of videos uses a very small set of UAV imagery I took in 2016-2017 over a portion of the American River College campus in Sacramento, CA.

UAV image data used in the videos:

Ortho Mapping using Pro

This video covers the first part of the photogrammetry process which includes the coordinate system definition to reference the aerial imagery (in this case UAV images), the interior orientation (relationship of individual image position at the time off collection) and exterior orientation (the relationship of each image to its neighboring images at time of collection and the relationship of each image to real ground space.

This process includes loading the images into the Ortho Mapping workspace and providing some parameters to conduct the interior and exterior orientation processes by using the Ortho Mapping workflow and the Adjust tool in the Ortho Mapping ribbon.

Create the Orthomosaic Image and DSM/DEM

The last part of the photogrammetry process is to create the color balanced orthomosaic and the digital surface model (DSM) or digital elevation model (DEM). With UAV data, most of the time, the elevation model is really a surface model since the surface model includes trees, buildings, and other structures vs an actual ground elevation model (i.e. bare earth surface).

A workflow exists in the Ortho Mapping ribbon to create the orthomosaic and surface model.