14 Aspects of Checking Quality of LiDAR data

  1. Always look at 100% of the data.
  2. Devise a series of steps that include what your looking for and how to locate the issues
  3. Analysis the data for new error not previously seen (ie. Sensor malfunctions).
  4. Scrutinize Sub contractor data more than in house data
  5. ALWAYS look for calibration errors.
  6. Use a check list based on past projects and continually modify the checklist based on new issues observed.
  7. Always check for accuracy on all LiDAR data sets
  8. Check the data based on the project requirements ( different projects have different specifications).
  9. Complete coverage of delivery area
  10. Correct LAS version
  11. Accuracy of classes used
  12. Removal of artifacts to meet specifications
  13. Removal of Buildings and vegetation to meet specifcations
  14. No over filtering of bare earth

The 5 most important aspects about processing LiDAR data?

We asked several LiDAR professionals what are the most important aspects of processing LiDAR and the following is a list of their co piled responses:

1. Quality GPS base staion data

2. Tight calibration lines

3. Flightlines of an apprioriate length to prevent IMU drift

4. Complete and concise collection documentation

5. Simple flight plans

6. Project organization

7. Solid Collection

8. Proper and vigorous GPS/IMU processing

9. Rigorous analysis of the terrian and vegetation in development of macros

10. Expereinced editors

11. Conduct S turns on every mission to help IMU find itself after long straight lines

12. Properly collected Data

13. Full coverage checks on every program.

14.  Good QA /QC

LiDAR FeedBack Anyone?

We would Like comments on what you would like to see on this blog regarding LiDAR.  Please submit ideas under the comments below.

Meteor Man and National Geographic?

Sanborn’s LiDAR field crew helped with technical inputs to a Meteor Man episode on the Science Channel. In addition, Sanborn’s  LiDAR collection of the Redwood forest  was featured on the National Geography Channel.  More details to come soon.!

Sanborn Using Optech’s Mobile Mapper

http://www.optech.ca/091211.html

The 5 most important aspects of A LiDAR collection?

Several LiDAR professional were asked to list the five  most important aspects of LiDAR collection. This is what they said in no certain order.

1. Well organized field collection plan

2. Trained Field Staff

3. Accurate Logs/data organization/ Organized field documentation

4. Prompt problem reporting

5.Virgous review of the collection area to account for terrian/elevation issues

6.  Good Ground GPS collection and use of high accuracy benchmarks

7.  Avoid flying in adverse weather conditions

8. Always use two Base stations on every mission

9.  Complete field verification of collected data

10.  Network Survey

11. Proper collection of calibration flight lines

12. Colleciton of  S turns

13. Baseline distances based on accuracy requirements.

14. Collection of ground verification data

Mobile LiDAR or MMS?

In two weeks we will start posting information on MMS (Mobile Mapping Systems)  aka. Mobile LiDAR.  We will post information on how the systems work, Applications,  and examples of this emerging technology. Please check in to learn more.

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ASPRS LiDAR Presentation

Title: LiDAR Acquisition Best Practices, QA/QC Procedures and accuracy assessment to Insure a Quality LiDAR Product to The End User

Presented By: Jamie Young

Date & Time: Thursday, April 29th 11:00am – 12:00

The presentation will cover all aspects of best practices for LiDAR data acquisition. The data acquisition of LiDAR is pivotal in providing a quality LiDAR product but it is important to have the necessary tools and knowledge to assess the qualitative and quantitative aspects of your delivered data set. The presentation will cover the best processes and procedures of a successful data collection and the necessary collection of control data for accuracy assessment. In addition, aspects of qualitative and quantitative assessment will be addressed to provide a better understanding of how to verify a LiDAR data set. It is necessary to have assurances that the LiDAR data delivered meets the requirements of the desired applications and specifications. This will be discussed. Lastly, a discussion of relative and absolute accuracies, their relationship to each other and the importance of assessing these accuracies as they relate to the quality your LiDAR project will be covered.

For more Information on the ASPRS conference Please click on the Link:  http://www.asprs.org/SanDiego2010/index.html

What Can I Do with My LiDAR Data?

The following is an example of products derived from LiDAR including Contours, Line work, elevation data and additional classification. The data was used for a transmission project. In addition to the LiDAR data digital Imagery was captured on the same platform using a Medium format DSS 439 Camera. A brief write up on the project is also provided below.

Transmission Mapping – The provider employed a LiDAR/digital camera coupled sensor for transmission mapping. The system can be mounted in either a fixed wing or helicopter platform to provide an array of products. Recently, The provider collected a forty linear mile transmission corridor using a fixed wing platform. The LiDAR data was collected at an average density of forty points per meter and RGB digital imagery data using a DSS 39 megapixel camera at less than 4 inch pixel resolution. The data was collected in two 4-hour missions using a twin-commander aircraft flying at 500meters AGL. The data was processed and delivered in 2 weeks. The products included classified LiDAR in PLScadd format including road, water bodies, drainage, man-made structures, distribution, transmission, and substation to name a few. Additional products included, two foot contours, line work, Ortho-imagery and surveyed information. The resulting vertical accuracy of the LiDAR data as checked against the ground survey is 4.23 cm RMSE. The horizontal accuracy was 10- 25 cm RMSE as checked against the ground survey. The data is being used for planning new line construction, permitting, environmental impact assessment and vegetation management. Addition uses include sway and sag analysis.