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The quality and pricing of aerial LiDAR can range significantly depending on where, when and how it is acquired. Several types of sensors with varying settings will provide good qualitative and quantitative LiDAR from any of the manufactures sensors. Numerous elements contribute to the success or failure of a LiDAR project such as: Where the LiDAR is flown and the vendor’s approach to collecting and processing LiDAR; when the LiDAR is collected; but how the LiDAR is collected and processed are probably the most important questions to answer for a successful project.
All these factors will affect the price, the quality and timing of a LIDAR project. Additionally, hungry times depending on the vendor always adversely affect the price of LiDAR. There are also economies of scale that drive the price down but are you really getting a better product? One thing is for sure and this continues to be the case for LiDAR: Quality, accuracy, and price go hand and hand when it comes to getting a good data set, not to say cheap is a bad thing. Picking the cheapest isn’t always the best option for all LiDAR projects. What about the innovation of Geiger Mode and Single Photo LiDAR and what this does to the market?
It is pretty clear that where the LiDAR is collected affects the price of LiDAR. The question should be is the cheapest price within line with the other prices received by other vendors disproportional to those prices. What are you receiving for that price? What is the experience of the cheapest price vendor? Where is the cheapest vendor located in relationship to the project location? For example if a project is to be flown in Alaska or the Pacific Northwest with significant terrain and vegetation and the cheapest price is 50% to 60% of the next nearest price. This should cause some concern and would warrant several questions about that vendor’s experience and why is their price much less than the others? In the example of Alaska, there are many factors that need to be considered in collection in Alaska that would not be valid in all parts of the Lower 48. Does this vendor have innovative solutions that drive their price down that the others don’t have? What is the success rate of this particular vendor in that geographic region?
Flying in a very flat area would seem to be much easier than flying in an area of steep relief and heavy vegetation but in some cases it may not be depending on the specifications. With the innovations done in calibration through additional tools and automation this is becoming less the case. Typically, flight line mismatches are less apparent in areas of higher relief. If a vendor has consistent calibration issues, there is a reason why you received such a great low price for your project. Additionally, what does the classification look like as it relates to your expectations? Unfortunately, better classification takes more time and experience plays a role in the results of classification because some manual interaction is still required for proper classification. There is continued improvement as it relates to the automation of classification and achieving a true bare earth model when that is required but even after 20 years, manual interaction is still a reality. So again, why is the price so much cheaper?
There are several factors that play in to the when component of the price of LiDAR. There are the obvious concerns and components to collection and processing of LiDAR like, snow free, leaf off, and no standing water. That being said, how could you benefit from the when? Unless you live in Arizona most LiDAR is collected in spring and fall. These two seasons in most parts of the world provide the best conditions as it relates to achieving the best bare earth model. In some regions very late fall and early winter provide the best time to collect LiDAR. How about locations where the leaves never completely come off the trees. Vegetation canopy is becoming a much less concerning component to good LiDAR collection as a result of improved point densities at altitudes that yielded much less densities in the past for the same cost. This is a result of better beam divergence, multi-return sensors and greatly improved repetition rates. Given that the highest demand for LiDAR collection is usually in the spring and fall a lot of vendors don’t have any collection in the summer and winter and typically, this will afford you better pricing during this time but at what cost is this and really is there a cost given the improvement of technology? Standing water, water elevations will always be a concern unless a topobathy sensor is used but again if the water is not clear you are back to square one.
How is the most important component to collecting any type of LiDAR including Aerial LiDAR. Having the latest and greatest LiDAR sensor is helpful to getting great LiDAR but it is just that, helpful. There are numerous LiDAR projects collected with older LIDARs that are much better than the latest and greatest LiDAR sensor collections. Experience is the key to how a LiDAR project is collected and processed. Using a very experience vendor with maybe not the latest and greatest almost always gets you a better LiDAR data set than someone with no experience and a brand new model. There are several reason for this. We in the LiDAR provider world are the beta test victims of all latest and greatest LiDAR sensors. Not to say that all latest and greatest LiDARs have problems but with new technology comes new challenges and we all have to work through these challenges at the expense of a good project. Typically, the challenges take anywhere between 6 to 12 months on any new sensor that is pushed into service without properly being vetted first. It is important to state that not all new sensors have problems and can’t be vetted but the profession has learned by experience that all new technology should be handled with kid gloves.
There are many ways to collect LiDAR and what is the cost of these ways? Are there efficiency improvements? Improvements in technology such as higher repetition rates, and is there absence of blind zones in the collection, which ultimately improve cost saving. This is only part of the how and definitely refreshing for both the vendors and recipients of the LiDAR data but there is much more to the how. How changes as it relates to the terrain, man-made, vegetation characteristics of the project area. For example, what is the flight line overlap? Flight line overlap is not just for making sure the project area is covered and the point density requirement is met. In areas of significant relief and terrain the resulting overlap can help with the sensors ability to get to the ground at different angles from adjoining strips. Additionally, even in flat areas this helps with getting to the ground in heavy vegetation. This comes at a cost because potentially this requires more flying depending on the sensor. Additionally, there is a reason why most vendors do not use a scan angle greater than 40 degrees and requirements sometimes specify much less scan angles. Please note that the prism mirror sensors typically operate at 60 degree and achieve similar result as the oscillating mirrors at 40 degrees. The reason for this is that the error in the data is greatly increased as you go past this amount of degrees.
Additionally, most Aerial LiDAR sensors operate the same with some minor differences so to say one sensor operates better than another is a little of a blanket statement. Standard configuration should yield good results but that being said any sensor is going to need a little adjustment to get the best result from the sensor and that is where experience comes into play. For example, working with four different serial number sensors from the same manufacture and the same model yielded very different results as far as noise and accuracy. All these sensors needed to be adjusted accordingly to meet the requirement of most LiDAR projects. Again, this is not always the case but more times than not knowing how to adjust the sensor is key to getting good data and experience drives the cost. Having to work the data in calibration and post processing after the fact takes more time and money to get a good data set if the experience is not there.
The weather will also drive the cost of LiDAR collection. The areas prone to bad weather usually take longer to collect or does it? There are several vendors that have adapted to this issue over the years but the question needs to be asked when selecting a LiDAR professional. Typically, weather days have greatly reduced as a result of more efficient and creative ways to collect in these project areas. Additionally, tide requirement areas have been adapted so that the entire project is not depending on tides and the flight lines are planned so that tidal areas can be collected during lower tide and the other areas can be collected whenever. This again reduces the cost to the end user.
Lastly, how the data is processed is critical to the cost of the project. Improvement in software and automation have greatly improved the efficiency which provides more competition as a result of cost reduction. Not all vendors are equal in this area and again experience and innovation is the key to this. Over the last 20 years we have learned a vast amount of hard lessons as result of trying to get the best data possible. For example, it is much cheaper to have the editing process done over seas. But is it? What is the cost to check all the data when it returns? What is the cost of a missed schedule as a result of re-work? How come the pilot data looks excellent from a sub-consultant but the rest of the project is bad? These are some of the questions that get frequently asked. This is not to say all overseas work is bad but why do most RFPs ask where is the work being done? Is the cost savings worth it? How is the data checked to make sure it meets all the requirements of the project specification regardless of where the work is being done is also an important aspect. Does the vendor and the client expect to do rework? Is this part of the cost? How much rework would be expected or is this prevalent for a given vendor or professional?
How is Geiger mode LiDAR and Single Pulse LiDAR going to affect the market price? Initial indication is that it can collect 10x or more data at much higher altitudes at much higher repetition rates. The results in data seems to be very favorable at first indication. There are currently several projects being conducted to determine the value of this technology as it relates to conventional LiDAR but it really does have potential to be disruptive sooner than later. This technology may not provide all the solutions to all projects but given technology there is always someone trying to figure out how to use new technology to improve efficiency, yield better results and provide cheaper solutions.
There are several LiDAR professionals who provide quality data using innovated solution to solve client’s needs and the cheapest price doesn’t always provide what is required to make sure that clients are getting what they need. Typically, paying more for a professional service yields better results and the market continues to show this. For some applications cheaper gets you what you need but we provide professional services. Similar to buying a car, can I live driving a lesser, cheaper vehicle, if the answer is yes than cheaper is fine. If the answer is no then I need to purchase a luxury car so all my needs and wants are met.
James Wilder Young (Jamie), CP, CMS, GISP is currently a Senior Geomatics Technologist for Merrick & Co. located in Greenwood Village, Colorado. His experience includes all aspects of LiDAR including sensor development, applications development, data acquisition, data processing and project management.
A 1.564Mb PDF of this article as it appeared in the magazine complete with images is available by clicking HERE