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I am new with GIS and I've been looking for ways on how I could create a NDVI map from LiDAR intensity and RGB image. Is there any way I could do this?

I have read that you could create an intensity image but then how can we merge it with the RGB image? Is there a GIS software for that?

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    Good call @Andre Silva--changed. – Aaron Nov 27 '14 at 14:59
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There is no specific GIS software for doing this: most will handle the RGB image and the Lidar data.

Basically, NDVI is (NIR - RED)/(NIR + RED). Most of the time, aerial Lidar gives you the NIR value (to be checked in metadata) and the first band of your RGB image gives you the RED value. Just make sure that your data are calibrated to reflectance (or, if not possible, normalised in the same range of value -> this will give you a good discrimination, but no absolute threshold can then be used).

As a remark, Lidar does not always provide the intensity information. Sometimes only the distance information is available.

  • Would that mean that I have to check one by one each LiDAR point cloud and find the closest pixel from the RGB image and then assigned the red value to that LiDAR point to calculate the NDVI value? – user84275 Nov 27 '14 at 15:35
  • you have the choice. There are tools to automatically extract the values of the rasters to the points, and there are tools to convert your point cloud into a raster that you combine with the image. The best choice will depend on the point density and the resolution of the image. – radouxju Nov 27 '14 at 19:18
  • could you tell me what are this tools? – user84275 Nov 28 '14 at 2:37
  • Please ask a software specific question depending on what exactly you would like to achieve (NDVI value for each point OR raster layer), the data format, the software that you could use (open source or proprietary) and what you have tried. Otherwise your question may become to broad. You can also edit your question with the steps where you are struggling. The name of the tools are quite generic and can be Googled together with the names of the software. – radouxju Nov 28 '14 at 6:47
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    Just a word of caution though that not all LiDAR systems operate in the NIR and you should check with the metadata to ensure that your dataset in fact does. Otherwise, NDVI will be out of the question from the LiDAR intensity. – WhiteboxDev Dec 3 '14 at 14:10

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