Discussion: JPEG2000 files question

I used to get image files from https://viewer.nationalmap.gov/basic/ They used to have two formats, regular JPG files with PNG georeferenced files included, and the JPEG2000 files. I have no problems with the JPG files loading into OCAD into the right position, but now these files are no longer there, and they only kept the JPEG2000. I have still not figured out how to convert these files so I can load them as backgrounds into OCAD 12 without losing the georeferencing information.

One option may be to use the free IrvanView software for Windows, and also install the free extensions for it, which includes a JPEG2000 plugin. You can then open the .jp2 file, save it at the same dimensions as a PNG file, and then rename the .jgw or .j2w worldfile (which contains the georeferencing info) to .pgw

On a Mac I think this worked for me:
sips -s format jpeg image.jp2 --out image.jpg

You could try GeoViewer (https://www.lizardtech.com/geoviewer-pro/overview). That worked for me converting MRSID files to something OCAD would handle.

I tried IrfanView which would change the format but lost the georeferencing but maybe the suggestion above works.

I'll try the non-Mac variant tonight, heading out as downhill ski instructor - even though all lessons might get cancelled by the time I get there - 0F and dropping fast.

Can you load them as a layer in QGIS? That's usually the first thing I try to do with strange georeferenced files. Who's tends to open most things pretty reliably.

@Canadian - I only now see QGIS is freeware? I always thought it was not ... or maybe there are different ones?

Yes, QGIS is open source. I really don't know much about it or really how to use it properly but seem to figure it out enough each time to fumble through what I need for basemap prep...

OK, I tried everything suggested... and more.... I don't seem to be able to extract/get/retain/whatever the georeferencing information. Is the georeferencing embedded in jp2 files, or would a jg2 have to be accompanying it somewhere?

Have you tried to convert JP2 data to GeoTIFF using GDAL?

There are probably world files (*.jgw) to go along with the jp2 files.

Another vote for GDAL! I like the latest MSVC 2017 x64 zipped 'complete' binaries from GISInternals

# translate from jp2 to geotiff
gdal_translate -of GTiff INFILE.jp2 OUTFILE.tif
# reproject to WGS84/UTM (change zone as appropriate)
gdalwarp -t_srs "+proj=utm +zone=18 +datum=WGS84" OUTFILE.tif FINAL.tif


If jp2 file has geo-referencing, you shouold be able to see it by printing out all metadata with exiftool

https://www.sno.phy.queensu.ca/~phil/exiftool/
https://www.sno.phy.queensu.ca/~phil/exiftool/exif...

From "examples":
Print all meta information in an image, including duplicate and unknown tags, sorted by group (for family 1).

exiftool -a -u -g1 a.jpg

@hughmac Thanks! It finally got it! Had one warning in the first step, but appears to not have affected the final file. I can just hope https://viewer.nationalmap.gov/basic/ does not change again so soon....

Sweeeet!! Nice job.