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Unmanned Spaceflight.com _ Image Processing Techniques _ Having trouble opening Europa map

Posted by: Antdoghalo Nov 3 2021, 01:42 PM

I recently found this map of Europa and GIMP is unable to open it despite my computer being able to open maps up to 64K in size and GIMP supporting JPEG2 files.
https://repository.hou.usra.edu/handle/20.500.11753/1412
Does anyone know how I can open this file?

Posted by: PDP8E Nov 3 2021, 05:45 PM

that file is 612-MB -- It is a JPEG 2000

you may just simply need to update your tools (photoshop. irfanview, -etc)

Ita also
// 25K pixels tall
// 49K pixels wide
// pretty!

Posted by: TrappistPlanets Nov 3 2021, 07:43 PM

QUOTE (PDP8E @ Nov 3 2021, 06:45 PM)

that file is 612-MB -- It is a JPEG 2000

you may just simply need to update your tools (photoshop. irfanview, -etc)

Ita also
// 25K pixels tall
// 49K pixels wide
// pretty!

what does the map look like (my pc won't be able to handle it, it too bulky for my pc)?

Posted by: Antdoghalo Nov 3 2021, 08:17 PM

Irfanview is unable to open this, GIMP just closes, and I cannot afford Photoshop.

Posted by: nprev Nov 4 2021, 12:00 AM

Topic moved to Image Processing Techniques.

Posted by: Bjorn Jonsson Nov 4 2021, 01:38 AM

I was able to open it in Affinity Photo.

An awesome map BTW that I hadn't seen before.

Posted by: Phil Stooke Nov 4 2021, 08:42 PM

This does point to the value of releasing images like this in different scales and formats. A version released as a PNG or JPG at 25% or 50% of the size would be all that most users would need. JP2 is not the most accessible format for the average user.

Phil

Posted by: Hungry4info Nov 5 2021, 12:37 AM

For the curious who want to see the image without dedicating 30 minutes to downloading and opening the file, here's a small preview of it.

Posted by: Tom Tamlyn Nov 5 2021, 04:10 PM

Thanks, very thoughtful of you.

That's a remarkable image of Europa, and quite unlike any that I can recall.

Posted by: TrappistPlanets Nov 9 2021, 11:58 AM

QUOTE (Hungry4info @ Nov 5 2021, 01:37 AM)

For the curious who want to see the image without dedicating 30 minutes to downloading and opening the file, here's a small preview of it.

wow that is gorgeous, also shadows in some areas are very prominent, so we could do some SFS dems (once we kill the albedo variation)?

Posted by: djellison Nov 9 2021, 10:42 PM

QUOTE (TrappistPlanets @ Nov 9 2021, 03:58 AM)

so we could do some SFS dems (once we kill the albedo variation)?

You can't do SFS on a mosaic like that. The lighting is different based on which bits of the mosaics are made from which source images and the lighting for those source images.

You must do SFS on the source images and then mosaic those outputs.

Posted by: stevesliva Nov 10 2021, 03:26 PM

Right, and as much as the shadows in the polar regions are large, maps tend to be made from images with a phase angle near zero for as much of the surface as possible, so that you see only albedo, not shadow. They'd excise the shadows at the poles if they could.