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Processed Flight Data Formats Part 1 - What’s What and What Is It For?

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Anyone who has worked with photogrammetry processing tools Pix4D and PostFlight Terra 3D have noticed an abundance of output options. This short 3 part series will describe Pix4D and PostFlight Terra 3D outputs as a starting point for expanding your photogrammetry processing potential.

Part 1: 3D

A PDF that contains 3D data. 3D PDF documents are completely interactive (manipulated in 3 dimensions) and can be annotated and measured using the Adobe Reader and Acrobat applications.

DSM and DTM stand for Digital Surface Model and Digital Terrain Model. A DSM is a model of the earth’s surface.  A DTM is a model of the earth’s surface with vegetation and other objects removed revealing the terrain. The term “scrubbing to ground” is often used for the process of creating a DTM from a DSM using either Pix4D/PostFlight Terra 3D’s point cloud editing tools or software like Global Mapper.  Either can be displayed in monochrome or any number of color indexes used to delineate elevation. DSM outputs from Pix4D/PostFlight Terra 3D are; .las, .laz, or .xyz.

A 3D Triangulated Mesh is a collection of vertices that define the shape of an object. Pix4D/PostFlight Terra 3D allow you to apply a mesh to a densified point cloud. Typically a mesh is used to see the shape of a data set since it fills in the gaps between points. Triangulated Mesh outputs from Pix4D/PostFlight Terra 3D are; .ply, .las and 3D-PDF.

Point Cloud
A Point Cloud is a set of data points arranged in a three dimensional coordinate system.  Points in the cloud are relative positions defined by x,y and z coordinates. The point cloud is the main data set used for creating all the 3D outputs in Pix4D/PostFlight Terra 3D. Point Cloud outputs from Pix4D/PostFlight Terra 3D are; .las .laz .ply and .xyz.

Contours represent terrain via a series of lines that delineate relief and relative elevation. Contours can be generated in a variety of resolutions and line spacing. Typically the contour map is the most important element in any cartographic representation of terrain. Triangulated Mesh outputs from Pix4D/PostFlight Terra 3D are;  .SHP, .PDF, and Auto CAD DXF/DWG

Stay tuned for Part 2 and Part 3 in the next few weeks!

Part 2: 2D:
GEO Tiff, KML/HTML, Map Box, Index Maps

Part 3: Animations and Triangulations:

In the meantime, if you have any questions regarding your UAV data, contact us today.