Laser Scanning and Surveying

The comments, and a few conversations I have had over the past week with some of you about the need for LiDAR and laser scanning training are helping to bring into clearer focus something that I have been struggling with for years. I think I want to call it the disconnect between laser scanning and surveying – not the profession of surveying, the science of surveying or what is more appropriately referred to as geomatics.

This is complicated. Laser scanning, especially tripod-based, is disruptive technology. By purchasing this black box you can find yourself in the surveying business where, if you don’t have a foundation in the science of surveying measurement, you are going to be at a disadvantage.

This is not the traditional surveying business and it is certainly not the land surveying business, it is the 3D measurement business, which perhaps should be thought of as a new professional category. It really should not come as a surprise to anyone that there is a lack of training in this field. It’s basically a new field.

It does not help that their are few standards to rely on and that in general the scanners themselves do not lend themselves to a common calibration protocol.

I think this has to change. There has to be a much tighter linkage between the application of laser scanning technology and the scientific foundation of 3D measurement. We have to get to the point where we all get the same answer.

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7 Responses to Laser Scanning and Surveying

  1. conor says:

    I would have to agree, and possibly one of the reasons is the ease (relative) whereby you can get a product that looks right very quickly using a laser scanner when compared to a close range photogrammetric survey, or an elevation/topo survey with a total station.

  2. Chris Siebern says:

    Gene,

    I appreciate the core issue of your post that the application of laser scanning needs to be based on the scientific foundation of 3D measurement. I disagree with your points that this constitutes a new field and that standards are a solution to the black box issues.

    Engineers, Photogrammetrist, Land Surveyors, Metrologists, whatever you want to call yourself, have been practicing the science of measurement for hundreds of years.
    While the technical ability to produce massive data sets has been disruptive, the notion that the introduction of an instrument that can measure angles and ranges to produce a set of 3D coordinates constitutes a new profession and a new science is disingenuous.

    Whatever your title, as a professional there is an obligation to understand the underlying science that the services you offer depend on. This does not have to permeate down to every technician in the company but here must be a person of responsible charge that has investigated the instrumentation and designed measurement procedures that will achieve the intention of the measurement system.

    In 2001 as a measurement system expert(3D), I was able to investigate and determine the capability of my cyrax 2500. I could determine how to integrate it with other measurement tools such as GPS and total stations. I was able to experiment and discover the limits of the instrument. I did not need a new profession or standards to do this. Lets not make distinctions based on the tools one can use. The distinction needs to be made more on the one who is using tools.

    To your comment on standards. Standards are a wonderful thing to establish a performance benchmark in a contract to define and communicate expectations. Standards do not guarantee a priori that the standard will be met. Measurement professionals still need to design a measurement system to meet the standard, evaluate the measurements, and then demonstrate that the desired result was achieved.

    Second the use of standards you are alluding to tends to stifle innovative uses of technology. If I am limited to perform measurements using a specific procedure or best practice that was established on old technology (old can mean 12 months with the rate of change in technology), I lose the benefit of adopting new technology that has innovated and improved the measurement systems. I

    What if I discover a data adjustment procedure that can reduce the required number of targets in half and and double the system precision. My standards might require 6 targets per scan and I need just 3. Lets be careful how we build these standards.

  3. Actually when you scan you are not measuring but acquiring 3D-images.

    My personal opinion is that rather than geomatic it is pretty much more Spatial Data information of assets. Besides you can or not extract geometric information or even create 3D documents of the assets or even match this upon existing 3D projects already existing…between others applications.
    I agree it is no measuring.

  4. Garth Archibald says:

    Traditional surveying where the data is realised using a projection is 2.5D.
    Point clouds created from laser scanner measurements, and they are measurements, are 3D.
    I think the issues that Gene is talking about arise at the interface between these two coordinate systems.

  5. Black Tripod says:

    Hi All, Technology is always moving onward, as measurement professionals (Surveyors / Engineers etc) it is the understanding of the measurement process that is the key here.
    Professional photographers have not dissappeared just because every mobile cell phone has a digital camera…… it is their skill and expertise that keep their profession alive. Laser scanners are still based on the fundamentals of an EDM, albeit a very fast EDM, still prone to atmospheric and reflectance issues…
    Standards are important because they level the playing field but education is the key. All measurement professionals need to keep their toes in the pool of knowledge and their fingers on the pulse of technology otherwise without embracing change our profession will die.

    I really have to stop writing blogs so late a night….

  6. Unni Krishnan says:

    Regarding the use of laser scanning technology, I think the surveying profession is in the same predicament as in the use of GPS receivers. For example, today there are people collecting GPS data:

    a) blissfully unaware of whether the receivers belong to the Consumer grade, Mapping grade, or Survey grade
    b) paying no attention to the different factors that affect GPS signals
    c) with complete disregard to the different real-time and post-processing correction methods

    Similarly, the new laser scanning instruments in the hands of a trained professional can produce high quality 3D data but can create havoc on 3D data collection projects in the hands of untrained technicians.

  7. Hugo Martin says:

    I agree with Gene and I can’t see how 3d measurement isn’t linked with geomatics regardless of the measurement system (technology)

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