0

I am trying to use the geolocation information of a tiff image to geolocate another. Both images are frames from the same drone footage, with the drone still over the same position. The one geolocated is a tif and the one to geolocate is a png, and it is to be converted to a tif. However, when I open the new tif in Google Earth Engine, I got it where I want it, but it's almost all white. I have also noticed that the stack created from the original .png has a fourth layer that should not be there, all of it at maximum spectral value of 255. Do you know hwat might be going on? I have also tried with the first image not as a png but as a tif without geolocation and the same happened. I have also tried with bricks instead of stacks. I tried first with rasters, but the result was even worse. All the image was white. Here is my code:

library(raster)
library(rgdal)
library(ggplot2)
library(dplyr)

## Loading image of interest as raster
R_test <- 
  stack("Pt6_clear.png")
R_test ## It does not have any CRS
plot(R_test)


## Loading image already geolocated from GIS
frame2 <- 
  stack("Pt6_frame2.tif")
frame2 ## 
plot(frame2)
# Give image of interest the lat/lon coords of the geolocated image as appear in its metadata in the console
extent(R_test) <- c(-9073461, -9073269, 2974255, 2974366)
# Copy the projection data of the geolocated image as appears in the console to the image of interest 
projection(R_test) <- CRS("+proj=merc +lat_ts=0 +lon_0=0 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs")
plot(R_test)

## Write new geolocated image into a file
writeRaster(R_test, "R_test_geolocated.tif", format = "GTiff")
1
  • 1
    The fourth layer might be a transparency/opacity layer. What if you plotRGB(frame2[[1:3]]), ie drop the fourth layer? Hard to be definitive without a copy of the file.
    – Spacedman
    May 18, 2021 at 19:26

1 Answer 1

0

This is a one liner using gdal:

gdalcopyproj.py source_file dest_file

See this question for more information: Using GDAL command line to copy projections

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.