LiDAR Applications in Surveying and Engineering

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1 LiDAR Applications in Surveying and Engineering 2013 NC GIS Conference Raleigh, NC Frank A. Alex Rankin, III PE, PLS

2 What is LiDAR? Light Detection and Ranging Analogous to RADAR, but using a different part of the electromagnetic spectrum RADAR uses radio waves or microwaves

3 What is LiDAR? LiDAR uses light at or near the visible spectrum (Visible spectrum occupies 390 nm nm) Aerial mapping LiDAR generally uses 1064 nm Yttrium-Aluminum-Garnet lasers

4 What is LiDAR? LiDAR uses the laser to illuminate a target and then analyzes the reflection The narrow laser beam makes it possible to map objects with a high degree of resolution

5 What is LiDAR? The basic technology has been around since the 1970s, but --- Because of size, cost and complexity had limited (government) application, but --- Recent dramatic advances in laser and detection technology, computational speed, and memory storage have made commercial applications possible

6 What is LiDAR? Smaller, faster, smarter LiDAR makes possible direct measurement of complex and hard to access structures

7 What is LiDAR Depending on the wavelength laser used, LiDAR can develop 3D point clouds of a wide range of objects, such as rocks, non-metallic objects, rain, chemical compounds, aerosols, clouds, and even single molecules

8 What is LiDAR For Surveying and Civil Engineering the most important applications are aerial scanning and terrestrial scanning

9 What is LiDAR Terrestrial Scanning creates 3D models of complex objects: piping networks, roadways, archeological sites, buildings, bridges, etc.

10 What is LiDAR One of the advantages of Terrestrial Lidar is that objects can be measured remotely making operations such as measuring roadways under traffic much safer.

11 What is LiDAR Aerial Scanning has many uses - measuring agricultural productivity, distinguishing faint archeological remains, measuring tree canopy heights, determining forest biomass values, advancing the science of geomorphology, measuring volcano uplift and glacier decline, measuring snow pack, and providing data for topographic maps - to name a few

12 Topographic Mapping In the past decade, because of the advantages of LiDAR, it has largely displaced Photogrammetry as the process for development of large scale topographic maps

13 Topographic Mapping (LiDAR Advantages) LiDAR sensors can be operated in any weather (not so with cameras- the clouds get in the way) LiDAR sensors are not affected by low sun angles - which would prevent useful photos

14 Topographic Mapping (LiDAR Advantages) IN FACT LiDAR can actually operate at night! More hours of useful flying per day means LiDAR offers greater efficiency, faster results, and can cover more ground than photogrammetry

15 Topographic Mapping (LiDAR Advantages) Rural and remote areas are easier and quicker to survey with LiDAR because each point has georeferenced location and elevation no orthorectification of image no network of photo panels required

16 Topographic Mapping (LiDAR Advantages) Photogrammetry needs to be able to see the ground to create contours LiDAR returns come from every object illuminated the lowest being the ground wherever the sunlight hits LiDAR will return XYZ

17 Topographic Mapping (LiDAR Advantages) LiDAR creates a 3D model directly from the returns Photogrammetry requires the incremental comparison of a pair of stereoscopic photographs indirect and much more labor intensive

18 Topographic Mapping (LiDAR Advantages) Photogrammetry requires contrast to see ground surfaces desert, wetlands, beaches, coasts are difficult or impossible LiDAR results come directly from the returned signal contrast not required

19 Public LiDAR Resources Public sources of existing LiDAR are valuable resources for engineering and surveying firms some addresses are: ges/cont-elev_v2.aspx

20 Public LiDAR Resources These public sources are excellent for large scale planning processes However!

21 Public LiDAR Resources North Carolina Board of Examiners for Engineers and Surveyors, says..in its Spring 2012 newsletter

22 Public LiDAR Resources As to the use of floodplain mapping LiDAR elevation data should not be used for final design or it could lead to disciplinary action

23 Public LiDAR Resources But properly used these public sources provide the base information for all types of planning processes, such as developing project specific hydrology models for large areas

24 Public LiDAR Resources or for developing land use plans for large residential, commercial, industrial, or mixed use areas.

25 Public LiDAR Resources..or for view sheds for parks, trails, and other large outdoor recreational areas.

26 Public LiDAR Resources.evaluating the relationship to environmental sites.

27 Public LiDAR Resources planning for greenways and other recreational amenities.

28 Public LiDAR Resources planning industrial sites.

29 Public LiDAR Resources industrial site selection by site selection consultants (hired guns).

30 Public LiDAR Resources and beyond initial planning the public sources can be used for large scale schematic grading exercises

31 LiDAR in Civil/Surveying Firm Terrestrial LiDAR (Scanning) can rapidly map complex sites in much more detail than is possible with conventional means this makes a better base sheet for design.

32 LiDAR in Civil/Surveying Firm and even if not complex, it covers areas that are large (but too small to fly) quickly.

33 LiDAR in Civil/Surveying Firm Imagine a building filled with piping.

34 LiDAR in Civil/Surveying Firm imagine crawling around that piping trying to locate it by direct measurement

35 LiDAR in Civil/Surveying Firm and the cost (and time) savings become obvious.

36 LiDAR in Civil/Surveying Firm For larger areas, site specific aerial LiDAR provides base sheets for all types of project specific civil engineering design such as

37 LiDAR in Civil/Surveying Firm Master Planning

38 LiDAR in Civil/Surveying Firm Grading...

39 LiDAR in Civil/Surveying Firm Utilities...

40 LiDAR in Civil/Surveying Firm Drainage Analysis.

41 LiDAR in Civil/Surveying Firm Erosion Control and Stormwater Treatment

42 LiDAR in Civil/Surveying Firm Roadway Design

43 LiDAR in Civil/Surveying Firm and much, much, more. The End!

44 LiDAR in Civil/Surveying Firm