AGTEK R & D Wiki

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A name isn't leaping to mind so we'll let the marketing people figure out what they want to say. 

====== Overview ======

This product is about handling large amounts of data generated from Drones (or Lidar) and massaging it into a result that can be used by 4D. The initial hope was that the drone software would create reasonable outputs suited to earthwork but for the most part that's not being seen. Our particular niche is to simplify the data reduction for our customers and create outputs that are usable.


===== Drone Data Outputs =====

There's some variations of file types used for transport but typical outputs are these:


  * **Orthomosaic** - the combination of individual pictures used to create the surface into a single large picture showing the overall site. The chief usage of this image is for identifying portions of the site where the trimesh data doesn't represent the earthwork. Structures, foliage, vehicles, building materials, etc. can be identified and the trimesh in those areas eliminated. A GeoTiff is one common output that has the advantage of being geolocated. PNG and jpg can be others but those formats don't appear to have any geolocation metadata and likely would have to be located manually. The challenge here is to not only read the file and geo-locate it if the location information exists but also downsample that result into something that can be read by Earthwork 4D. Some Tiff examples have exceeded 350mb (28000 x 280000) which is far greater than is wanted or needed.
  * **Trimesh** - The surface representation created as a depth-map from processing the overlapping photos. The issue here is the level of resolution generated by this process is often overkill for representing earthwork and often contains areas and objects that should not be used for earthwork surface calculation. The goal of our program is to reduce the data set in a way that's insignificant for earthwork volumes but with an eye for display and calculation efficiency. Along those lines, the combination of displaying the trimesh over the orthomosaic makes it relatively easy to identify and eliminate inappropriate point/triangles that are not the earthwork surface. File types that may be encountered are: 
       * LandXML
       * DXF/DWG
       * OBJ - not a current format but an open source format. 
  * **Contours** - Some software outputs contours which has advantages and disadvantages as a medium. The chief advantage is the natural filtering and data reduction that contours represent. We may want to do compression upon those contours but for the most part they are straightforward. They are also an easy method to visually digest the surface in a planview.There are several negatives including:
         * A tendency to smooth too much which masks surface data that should not be included. For example, the Kespry contours include equipment and structures rendered down to contours that look remarkably natural. 
         * It's more difficult to currently clip small areas cleanly because a contour may run through an invalid area while still being good in another part of the site. That could perhaps be finessed with a different deletion method.


==== Input file types ====


==== Output types ====

  * ESW\ESZ
  * DXF/DWG - maybe not so 4D is the only reader
  * LandXML - Only 4D




==== Resources for mesh optimization and reduction ====


Meshlab is NOT user friendly but is a way to look at different formats and outputs. It also has a wealth of tools for mesh decimation which gives a starting point for Google searches

[[http://www.meshlab.net/|http://www.meshlab.net/]]
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