gdalwarp: Syntax

Question

In GDAL, I have seen the sample line:

gdalwarp $(list_of_tiffs) merged.tiff

I would like to merge images to create a mosaic, but can't use gdal_merge (need an exe file), e.g to merge C:\Temp\image1.jpg with C:\Temp\image2.jpg. Can someone give me an example for the command above?

Answer 1

The vrt way is the better way, but as an answer to what you asked:

From the gdalwarp manual page http://www.gdal.org/gdalwarp.html you can read the last two parameters srcfile* dstfile

and from the parameter exlanations:

srcfile: The source file name(s). dstfile: The destination file name.

So, the syntax is

gdalwarp -of GTiff -s_srs epsg:4326 -t_srs epsg:3857 input_1.tif input_2.tif input_3.tif output.tif

If you want just a mosaic in the source projection and into GeoTIFF format which is the default use can do it with a short command

gdalwarp input_1.tif input_2.tif input_3.tif output.tif

Answer 2

You can do it in two steps. Note that in most cases you don't need to create a new file if you use a vrt.

gdalbuildvrt output.vrt C:\Temp\image1.jpg C:\Temp\image2.jpg

but if you REALLY need a unique file, then you can then translate it (or warp it if you also need to change the srs of the dataset)

gdal_translate output.vrt output.tif