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My organization is considering hiring a company to capture new LiDAR data to help with current stormwater issues that we are currently experiencing. I am a GIS analyst that has been assigned with this task.

Our current quote is for roughly 70 square km and the project deliverables will include:

  • 1m resolution orthophoto TIFF imagery.
  • 50cm resolution orthophoto TIFF imagery.
  • Tiled 11cm resolution orthophoto TIFF imagery - each image delivered in ATS sections.
  • LiDAR data collected with approximate 7 points per sq meter.
  • Raster bare earth DEM produced from the LiDAR data. Two files will be delivered:
    • 1 - 50cm grid spacing.
    • 1 - 1m grid spacing.
  • 6 new survey checkpoints.

We have been quoted roughly $30000 CAD (canadian dollars).

  1. Is cost of new LiDAR data reasonable for deliverables provided?
  2. What else should be considered when hiring aerial LiDAR survey?

Any feedback would be great. I have never had the luxury of being included in data purchases so this is all new to me.

closed as too broad by PolyGeo Feb 2 '16 at 0:00

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    Just to clarify, you are paying a company to gather NEW lidar data, not sell you existing data? What area of Canada? – Radar Sep 29 '14 at 16:28
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    Yes we are paying a company to gather the new current data. We are in Alberta. – PeopleUnderTheStairs Sep 29 '14 at 16:29
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    I worked at a company in the US that flew orthos and LiDAR. I wouldn't say the is a bad quote or a good quote. Will the company perform any classification. I am sure they may for the production of the DEM, but it may be useful to get the classification results as well. What is the X,Y,Z accuracy? – Ryan Garnett Sep 29 '14 at 19:48
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    @PeopleUnderTheStairs Yes, that figure seems inline with the cost of new LiDAR dataset acquisition for other projects in Canada (southern Ontario) that I know of. One thing that I would strongly recommend getting the raw LAS files (point clouds) from which your bare earth DEMs will be generated. Later on, when you want to use alternative algorithms for processing the data, you can always go back to the point cloud. Make it a requirement and it shouldn't cost any more. – WhiteboxDev Sep 29 '14 at 21:03
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    @RyanGarnett i have submitted your suggestions to be included into the deliverables. Thank you – PeopleUnderTheStairs Sep 30 '14 at 19:51
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It actually seems very reasonable from a price perspective. I would specify it meets XXXX standard of accuracy and I would specify the file be in las 1.2 (or another spec as desired). Specify the classes you require and the RMSEz that is acceptable (often just vertical in lidar). 7 points per m is high.

I find this document very useful. It spells out what FEMA expects from a lidar vendor line by line.

I would say that your two major issues are not specifying the classes required and not specifying the accuracy level.

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    @User27239 Extra costs will be added to Classify the data. The horizontal accuracy on the ortho will +/-35cm w/ 90% confidence and the horizontal accuracy will be +/- 28cm. The LiDAR data vertical accuracy will be +/- 25cm w/ 90% onfidence with the horizontal accuracy of +/- 16cm w/ 90% confidence. Thanks for the help. – PeopleUnderTheStairs Oct 2 '14 at 17:05
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    Good stuff, it sounds like you are on top of it (usually they use .95 not .90) but maybe that is cost based. – If you do not know- just GIS Oct 2 '14 at 17:43
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It is usually more meaningful to compare quotes from different providers for the same situation/contract. However, I tried to make a rough comparison with the work of Hummel et al. (2011).

  1. OP.

30k CAD / (70 Km² x 247.105 acres/Km²) = $1.73 CAD/acre or $1.92 USD/acre.
(Considering a ratio of CAD/USD = 1.11 in Oct/2014).

  1. Hummel et al. (2011).

They report in Table 4, a cost for acquisition and processing of LiDAR data (6.31 points/m²), in Oregon/USA in 2007, equal to $2.62 USD/acre (in 32k acres).

Based on such comparison, it seems a reasonable price; it is a lower value than a cost in 2007 (had it brought to present value it would be greater), for a similar point cloud density. On the other hand, the deliverables are different, so as the terrain and land cover will also probably be.

About things to be considered in the hiring process, besides the points raised in If you do not know - just GIS' answer (specifying classes and checking vertical/horizontal accuracies), the following ones are also worthy attention:

  • make sure the contract states a timeline and deliverables (stated by Nick O).

I find Reutebuch et al. (2005) recommendation (in pages 290 and 291) very useful about which products should be delivered by providers; at least: (i) bare-earth elevation model, (ii) canopy height models (CHM), (iii) canopy cover maps, (iv) LiDAR intensity images, (v) all returns dataset. They also state:

At a minimum, this data set should include pulse number, return number, east coordinate, north coordinate, elevation, and return intensity for each LIDAR return and metadata documenting the LIDAR mission flight parameters, sensor type and settings, GPS control, horizontal and vertical datum, coordinate units and projection, and date and time of mission. Ideally, all return data files should be in the American Society for Photogrammetry and Remote Sensing LIDAR data exchange format (.las).

  • get the raw LAS files (point clouds) from which the bare earth DEMs will be generated. Later on, it is possible to use alternative algorithms for processing the data, one can always go back to the point cloud. (stated by WhiteboxDev).

  • it is interesting to specify that 7 pts/m² is the minimum return density required in x% (e.g., 95%, 99%, 100%, etc) of the cover area. Otherwise, the return density average could be achieved, but with a standard deviation so large that the return density would not be satisfactory in some areas.

  • also, specify what happens if the contract agreements are not delivered (e.g., resurvey, get a discount, etc).


References.

- Hummel, S., Hudak, A. T., Uebler, E. H., Falkowski, M. J., Megown, K. A. (2011). A Comparison of Accuracy and Cost of LiDAR versus Stand Exam Data for Landscape Management on the Malheur National Forest. Journal of Forestry, 109(August), 267–273.

- Reutebuch, S.E., Andersen, H.E., McGaughey, R.J. (2005). Light detection and ranging (LIDAR): an emerging tool for multiple resource inventory. Journal of Forestry, 103(6), 286–292.

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In addition to the points in the other answers, make sure that you have well defined control points and callibration. You will get the most use out of LiDAR that you can compare from collection to collection. If a company will not provide you with this data, it is best to pay a little more. I have come into a project to find that there is no way to compare the second file to the first, due to lack of control points.

One thing that I recommend is to search for "LiDAR Lessons Learned" both with and without 'stormwater' or other potential uses for your collection. Utah DOT has a paper on 'Calibrating the Point Cloud which includes lessons learned. North Carolina has Lessons Learned on flood data LiDAR collection

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