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I'm trying to merge some LiDAR tiles together but when I do, the clarity of the image drops, so I think that means I am losing some data.

How do I merge the tiles and keep all of the data and the clarity of the LiDAR?

Before merge:

Lidar before merge

After merge:

Lidar after merge

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  • White areas in the first image and black areas in the second image can have nodata value. Color values of other pixels may be scaled after merging. May 8, 2018 at 9:59
  • So it's just the colours that have changed then?
    – Nuthatch
    May 8, 2018 at 10:41
  • Possible duplicate of Failing to merge rasters in QGIS May 17, 2018 at 18:03

2 Answers 2

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Legends show the merged file has a wider range of values (0 to 74.71 m) than each tile individually (which is expected), while the extreme colors in the pallete are the same (black to white). This will make color contrast in the merged file less apparent. See picture below (merged file is marked in red; tiles in green):

enter image description here

However, it seems none of your tiles have values near or equal zero, so maybe no data values were converted to zero, or somehow they are appearing in the legend as zero. Check the layer symbology.

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  • If I change the min value in symbology to the lowest value that is found in an individual tile, would that solve my problem?
    – Nuthatch
    May 9, 2018 at 17:16
  • @Nuthatch, would it? Why didn’t you try and let us know :/ ? What is the min value? Do “zero” values really exist? How the symbology is treating “no data”? How “no data” was set before and after the merge? Please, based on provided hints in answer; do some research, make some tests and let us know the results. Tks. May 9, 2018 at 18:12
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I edited the min value to the lowest value found in the individual tile data (31.879) and from what I can tell the colour table now shows all of the data correctly.

Merge with changed min value

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