[RS-ecology] Help on Image Merge Issues

[Adebola Hassan]

Hello.

I am trying to merge a few tiff images (each has 4 bands) in R and It was
partly successful.

However a look (in QGIS) at the merged output revealed some sort of
radiometric distortions in the output file.

I would appreciate help in this regard.

Please find below my source code in R.

I attached to this email also (for comparison) one of the image before
merging and the same image section in the merger output.

Thanks - Adebola Hassan

#Rcode
#list all tif files in working directory
all_tiff_list = list.files(".", pattern = "tif", full.names = T)

#plot first img only
all_tiff_imgs1 = stack(all_tiff_list[1])
plot(all_tiff_imgs1)

#merge and plot first and second tiff file
all_tiff_imgs2 = stack(all_tiff_list[2])
tiff_merge_1_2 = merge(all_tiff_imgs1, all_tiff_imgs2)
plot(tiff_merge_1_2)

#merge and plot all tiff files
img_list = list()
for (i in 1:length(all_tiff_list)) {
  img_list[i] = stack(all_tiff_list[i])
}

img_list$filename <- 'test.tif'
img_list$overwrite <- T
all_img_merge = do.call(merge, img_list)
plot(all_img_merge)
ggRGB(all_img_merge, r = 1, g = 2, b = 3)

#image after merge
[image: Merged_Image.PNG]
#before merge
[image: Single_Image.PNG]
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