In all of my presentations, discussions and travels, I am almost always asked what makes a good Mobile LiDAR project? It is a difficult question to answer quickly and sufficiently. As an experienced Project Manager that has completed the coursework from the Project Management Institute, I know that a project is a temporary endeavor undertaken to create a unique product, service, or result. My experiences tell me the uniqueness of scope, location, terrain, jurisdiction (with specific standards and specifications) and similar influences present a challenge in determining the suitability of applying the Mobile LiDAR tool to complete an assignment. There are, however, key characteristics that provide a means for evaluating if the technology is well suited. They include:
Level of Detail
Schedule
Safety
Access
Security
Level of Detail
The complexity of feature extractions or modeling (digital terrain models or 3D analysis) is often the primary driver for the use of Mobile LiDAR on a project. The greater the volume of features/products that need to be produced, the more likely Mobile LiDAR becomes the optimal tool for deployment. The resolution and completeness of scan data affords the opportunity to perform complex extractions of topographic features and develop high density digital terrain models. Typically, Mobile LiDAR is a highly efficient tool for complex corridors which contain many manmade and topographic features such as: above ground utilities, curb/gutter, sidewalks and intersecting roadways. The software tools readily available to exploit point cloud data, combined with the speed of collection provided by the Mobile LiDAR, are more efficient than a rod person directly locating individual objects.
This image shows a railroad corridor with complex catenaries which were extracted from the Mobile LiDAR point cloud in addition to other railway features.
Schedule
In todays business climate, the adage better, faster, cheaper is the standard to work by. It used to be that you had to sacrifice one or two, but couldnt have all three. However, with the careful application of technology and traditional field staff, project durations can be greatly reduced without increasing project cost or sacrificing quality. Project activities can be closely scheduled to identify concurrent activities to maximize efficiencies. For example, Mobile LiDAR is not constrained by performing scanning activities to daytime operations. Schedules can be shortened by deploying traditional survey crews during the day to set and observe ground control, as well as to capture features within obscured areas.
Safety
Our nations highways can be very dangerous places to work; so much so that most states have implemented increased fines in construction zones. Often survey crews are on the scene before temporary Jersey barriers and other traffic control devices are in place making their only protection the signage required by Maintenance of Traffic (MOT) rules. Mobile LiDAR can minimize exposure of field staff to dangerous roadway conditions by capturing survey data at normal driving speeds, and thereby relegating traditional surveying activities to areas well outside of the travel lanes. Safety concerns for transportation related projects also need to be considered for the motorists traveling within the survey area. Conventional practice for traditional surveying along heavily congested roadways would dictate lane closures and additional signage; effectively creating temporary hazards for the unsuspecting motorist. Mobile LiDAR can eliminate that hazard and alleviate impacts to travelers.
Access
Closing or limiting access to travel lanes, runways and rail lines are often not an option for a project. Being able to rapidly and efficiently collect information without impacting normal operations is a crucial component of Mobile LiDAR. The operation also limits the use of escorts (airfields) or flagmen (railroads) when performing survey activities. The use of these resources may not have a direct cost impact you, but they definitely do for your client.
Security
Perhaps the rarest condition for identifying Mobile LiDAR as a necessary tool is security. There have been several instances where we deployed Mobile LiDAR to minimize staff exposure to somewhat hostile environments or conditions. These projects were not only in undesirable locations, but our clients protocols required the use of security often utilizing multiple officers during a 12 to 14 hour working period. By utilizing Mobile LiDAR over traditional methods, we were able to minimize the duration of field activities and alleviate the need for additional security resources.
A security detail is assigned to the Mobile LiDAR crew. During a 12 to 14 hour work day, multiple shifts of officers were utilized. Capturing the required data quickly reduced the burden to the agents.
Reality Check
When you consider each of the elements in the decision making process, more often than not, it boils down to the dollars and cents. There are scenarios where Mobile LiDAR is not the most cost effective solution (small survey area or limited number of required features, among others). In those instances, it is important to effectively communicate that to your client, and allow them to make informed decisions