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EXIF Location


kanchan
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I just noticed this in one of the logs I happened to have read. Am I the last puzzle/multi/Wherigo/letterbox cache owner out there who was not aware of it? (I'm talking about the EXIF location information shown just like this, and this particular log is just fine as the photo was not taken at the GZ.)

 

15252579_10154061568084212_1526525278353141360_o.jpg

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I assume you're running some sort of GreaseMonkey script to tweak how log images are displayed, right? Because I never see anything like that on a cache log.

 

Cameras will store coordinates (some cameras anyway), plus all sorts of extra info (shutter speed etc.) inside JPG images in an area called, you guessed it, EXIF. A few years ago Groundspeak started stripping that out of newly-uploaded images (well, I thought they did!) to avoid people inadvertently giving away the locations of puzzle finals.

 

This is my favorite tool for sniffing through EXIF data: http://regex.info/exif.cgi

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I assume you're running some sort of GreaseMonkey script to tweak how log images are displayed, right? Because I never see anything like that on a cache log.

 

Cameras will store coordinates (some cameras anyway), plus all sorts of extra info (shutter speed etc.) inside JPG images in an area called, you guessed it, EXIF. A few years ago Groundspeak started stripping that out of newly-uploaded images (well, I thought they did!) to avoid people inadvertently giving away the locations of puzzle finals.

 

This is my favorite tool for sniffing through EXIF data: http://regex.info/exif.cgi

Ah, yes. I just remembered that I had been using this, and also confirmed that that script is the one which is showing this information right there. For some reasons, I had never noticed it before. Yes, I knew about EXIF. I was just surprised seeing the information right in front of my eyes just by casually reading the log on the web site.

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Ah, yes. I just remembered that I had been using this, and also confirmed that that script is the one which is showing this information right there. For some reasons, I had never noticed it before. Yes, I knew about EXIF. I was just surprised seeing the information right in front of my eyes just by casually reading the log on the web site.

 

The Project-GC script was recently updated to display that info. You can turn it off as it's an option. With the option off it won't preview the image and show the location info if it is present.

 

 

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I was sure that the exif was being stripped out last time I checked a Groundspeak hosted photo ( I like puzzle caches, and the presence of externally hosted photos makes me look at them closely ... there are various ways they can conceal info a Groundspeak hosted pic couldn't ...)but I just checked a photo I uploaded to a new listing of my own, and sure enough, exif info is there. Interesting !

I'd be interested to know if this is a temporary thing, or the new norm.

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What surprises me is this: Groundspeak is still allowing EXIF coords to sneak through, even though I'm pretty sure they made an explicit move a few years back to prevent that. Didn't they? How long did that last?

 

Isn't this a bug?

Yes, I remember that. I think some puzzle cache owners complained about it -- they intentionally embedded the GPS location in one of the images in the puzzle, and the HQ stripped that off. They probably didn't know they could just host such images files elsewhere. But that is just my guess.

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Ah, yes. I just remembered that I had been using this, and also confirmed that that script is the one which is showing this information right there. For some reasons, I had never noticed it before. Yes, I knew about EXIF. I was just surprised seeing the information right in front of my eyes just by casually reading the log on the web site.

 

The Project-GC script was recently updated to display that info. You can turn it off as it's an option. With the option off it won't preview the image and show the location info if it is present.

That makes sense. I only checked the current code. I don't need to disable it personally.

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I was sure that the exif was being stripped out last time I checked a Groundspeak hosted photo ( I like puzzle caches, and the presence of externally hosted photos makes me look at them closely ... there are various ways they can conceal info a Groundspeak hosted pic couldn't ...)but I just checked a photo I uploaded to a new listing of my own, and sure enough, exif info is there. Interesting !

I'd be interested to know if this is a temporary thing, or the new norm.

They were stripping of the EXIF (or just the GPS location) for a while, and they changed it back. My guess is that someone complained about it (probably because they don't know how to host images elsewhere, and wanted to retain the EXIF).

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What surprises me is this: Groundspeak is still allowing EXIF coords to sneak through, even though I'm pretty sure they made an explicit move a few years back to prevent that. Didn't they? How long did that last?

 

Isn't this a bug?

 

Anyone can add any exif filed they want as long as they follow format protocol. Last I checked, there were 26 widely used schemes for geographical coordinates in Exif, and probably hundreds of less common schemes. It is probably not reasonable to identify and remove them all. While one could just remove all exif data, doing so could mean legal trouble, because some users embed copyright notices in the exif.

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What surprises me is this: Groundspeak is still allowing EXIF coords to sneak through, even though I'm pretty sure they made an explicit move a few years back to prevent that. Didn't they? How long did that last?

 

Isn't this a bug?

 

Anyone can add any exif filed they want as long as they follow format protocol. Last I checked, there were 26 widely used schemes for geographical coordinates in Exif, and probably hundreds of less common schemes. It is probably not reasonable to identify and remove them all. While one could just remove all exif data, doing so could mean legal trouble, because some users embed copyright notices in the exif.

A while back I had a puzzle cache with vital information hidden away in the copyright field of an image exif: it had worked fine for a while, then a cacher asked for help with solving, and I found the exif had vanished, copyright notice and all. :mad: I uploaded a new picture with doctored exif, still nothing showing, and just reworked the puzzle.

 

I saw no mention from TPTB of the exif stripping back then, or the exif return now. It would have been useful to have, say, a mention in the weekly e-mail rather than it telling me about upcoming megas in other continents ...

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What surprises me is this: Groundspeak is still allowing EXIF coords to sneak through, even though I'm pretty sure they made an explicit move a few years back to prevent that. Didn't they? How long did that last?

 

Isn't this a bug?

 

Anyone can add any exif filed they want as long as they follow format protocol. Last I checked, there were 26 widely used schemes for geographical coordinates in Exif, and probably hundreds of less common schemes. It is probably not reasonable to identify and remove them all. While one could just remove all exif data, doing so could mean legal trouble, because some users embed copyright notices in the exif.

A while back I had a puzzle cache with vital information hidden away in the copyright field of an image exif: it had worked fine for a while, then a cacher asked for help with solving, and I found the exif had vanished, copyright notice and all. :mad: I uploaded a new picture with doctored exif, still nothing showing, and just reworked the puzzle.

 

I saw no mention from TPTB of the exif stripping back then, or the exif return now. It would have been useful to have, say, a mention in the weekly e-mail rather than it telling me about upcoming megas in other continents ...

You can always use a third party image hosting service, but I agree with you about the lack of communication in general. It's my bad that I blindly assumed the TPTB did this thing, but I think they deserve it. ;-)

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We have never intentionally retained nor stripped EXIF data. We take the photo as uploaded and generate various versions of the image for different uses (e.g. as a thumbnail, for use in a log, etc.) and in some cases resize the original if it is bigger than certain limits that I do not have at my fingertips at this moment. During these processes, which use third-party software modules, EXIF data may or may not get stripped, as might be the case when the images are stored in the cloud, which we started doing approximately three years ago. If retaining EXIF data is critical for you in an image, you will want to upload it to a third-party site dedicated to image hosting.

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We have never intentionally retained nor stripped EXIF data.

Very artfully worded. :grin:

However, this doesn't seem to be true. You yourself posted the following back in 2011:

I'll be following up on this issue this week. We never used to strip EXIF data, but in December I was informed that we had started doing so for privacy reasons. We then implemented a new image handler earlier this year and I have now been told that we are not intentionally doing anything with the EXIF data. I'll be asking those who make the decisions what our plan is going forward.

It sounds like maybe there was some miscommunication at GSHQ at the time, where some people thought you were supposed to be stripping EXIF and some thought you weren't?

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My apologies - I was wrong (I guess that age is catching up with me). I tracked down our dev who worked on the image handler that we are currently using and he says that he believes that at one time we did in fact strip EXIF data. That was apparently just for a short time prior to the implementation of the new handler. In any case, the handler on the web site currently does not alter the EXIF of the originally uploaded image (apps, however, may be behaving differently).

 

It's important to note, however, that this could change at any time, and manipulating a photo on the site (rotating, etc.) may affect EXIF data. So, if you want EXIF data maintained for a photo that you are using, it's best to use a third-party site dedicated to image hosting and link to that.

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My apologies - I was wrong (I guess that age is catching up with me). I tracked down our dev who worked on the image handler that we are currently using and he says that he believes that at one time we did in fact strip EXIF data. That was apparently just for a short time prior to the implementation of the new handler. In any case, the handler on the web site currently does not alter the EXIF of the originally uploaded image (apps, however, may be behaving differently).

 

It's important to note, however, that this could change at any time, and manipulating a photo on the site (rotating, etc.) may affect EXIF data. So, if you want EXIF data maintained for a photo that you are using, it's best to use a third-party site dedicated to image hosting and link to that.

Thanks for the update. I had to refer back to old posts to confirm what I was saying, so my memory isn't much better than yours! :laughing: I agree that third-party sites would be more reliable in this respect for cache description images.

 

Personally, I see more of a problem with EXIF data being unknowingly retained on cache log images, because this can lead to people inadvertently spoiling puzzle caches. With the ever-increasing use of smartphones to take photos, the chances of someone uploading a geotagged photo from the location of a puzzle final is becoming much more likely (that reminds me, I need to check for such photos on my puzzles). A great improvement to the website and/or app (and third-party apps, too) would be to automatically strip the EXIF from photos when uploading to a log on the cache types where coordinate information could spoil it (ie. Mystery, Multi, Letterbox, Wherigo).

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Personally, I see more of a problem with EXIF data being unknowingly retained on cache log images, because this can lead to people inadvertently spoiling puzzle caches. With the ever-increasing use of smartphones to take photos, the chances of someone uploading a geotagged photo from the location of a puzzle final is becoming much more likely (that reminds me, I need to check for such photos on my puzzles). A great improvement to the website and/or app (and third-party apps, too) would be to automatically strip the EXIF from photos when uploading to a log on the cache types where coordinate information could spoil it (ie. Mystery, Multi, Letterbox, Wherigo).

I very much agree to this view.

I guess it would be sufficient to just remove the geo-location data from the EXIF-data.

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I guess it would be sufficient to just remove the geo-location data from the EXIF-data.

That's what I was originally thinking too, but AustinMN posted this that would mean removing all EXIF would be the way to go:

Anyone can add any exif field they want as long as they follow format protocol. Last I checked, there were 26 widely used schemes for geographical coordinates in Exif, and probably hundreds of less common schemes.

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I don't have an opinion about if EXIF should be stripped or retained, there are good arguements on both sides.

What I do have an opinion on, is that website users should be made aware of changes, and informed of the need to turn off tagging to keep mystery/multi/Wherigo final locations private, or conversely the inadvisibility of using EXIF as part of a mystery cache puzzle.

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I assume you're running some sort of GreaseMonkey script to tweak how log images are displayed, right? Because I never see anything like that on a cache log.

 

Cameras will store coordinates (some cameras anyway), plus all sorts of extra info (shutter speed etc.) inside JPG images in an area called, you guessed it, EXIF. A few years ago Groundspeak started stripping that out of newly-uploaded images (well, I thought they did!) to avoid people inadvertently giving away the locations of puzzle finals.

 

This is my favorite tool for sniffing through EXIF data: http://regex.info/exif.cgi

Ah, yes. I just remembered that I had been using this, and also confirmed that that script is the one which is showing this information right there. For some reasons, I had never noticed it before. Yes, I knew about EXIF. I was just surprised seeing the information right in front of my eyes just by casually reading the log on the web site.

 

Thanks for letting me know about this script.

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