Past Projects

LiDAR Survey to support local Council development of active travel are

MDC Geospatial conducted a LiDAR survey  along a proposed 2km route with a 250m buffer each side of the road. Over 30 high quality Ground Control points were installed across the extents of the project site. Of these, 10 were held back as independent check point verification confirming an RMSE of 0.048 m.  

The LiDAR flights were a chunky 19GB of RAW data! 

Error Reporting beyond the software

''It's a common industry misconception that software generated error reports represent absolute accuracy.''

It is unfortunately unreliable to take this information and present it as a fact when most/all LiDAR and Photogrammetry software will treat the supplied control and  checks as 'perfect error free' coordinates which is unfortunately impossible. 

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We took our reporting through the necessary steps outside the software by quantifying control uncertainty, then independently propagating these variables into our final estimates, we provided an accuracy statement expressed at a 2σ (95%) confidence level. This gives our clients the peace of mind that the data isn't just "good on paper," but statistically proven and technically sound for high-stakes engineering decisions.

Rigorous Control paired with PPK workflow

As with all projects of a similar nature, the first day was exclusively dedicate to establishing robust control networks and check points networks to statistically prove the quality of our data.  This also gave us the opportunity to adjust the desk based planning for compliant drone flights across the project site. based on site conditions. 

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We logged raw GNSS observations before during and after our flights. The raw data form both the GNSS receiver and from the drone were then used to remove systematic errors which affect the satellites calculated position such as atmospheric delays and satellite clock errors. 

This method gave higher confidence in elevation accuracy for terrain modelling and improved reliability in areas with poor mobile network coverage.

Deliverables

1. High-Resolution Orthophoto (2D Map) as a GeoTIFF file enabling cm level measurements within QGIS, ArcGIS, AutoCAD/Civil 3D etc. 

2. LiDAR Data (Classified Point Cloud) which  separates "Ground" from "Non-Ground". Additional algorithms can be run for analysis on trees or infrastructure condition.

3. DTM vs. DSM (The Terrain Models)

• DSM (Digital Surface Model): This includes everything, the ground, the warehouse roof, trees, and vehicles. It represents the "first return" of the laser.

• DTM (Digital Terrain Model):  this is the "bare earth" model with surface features such and buildings and trees removed.