Hi all,

We had a couple of major tasks that we were hoping to finish around the middle of this year, but for one reason or another the tasks ended up being put off until now.

One of these things is a follow-up on the annotation tool display bugs that were fixed back in June (see this blog post). Although the bugs were fixed, we promised to follow up with an assessment of the potentially affected images, and that's what we're (finally) doing in this blog post.

Zoom-in issue

A recap of the issue:


In the annotation tool, when you zoomed in far enough (generally 5 times or more, but could vary slightly), the image would start to appear squashed horizontally. This caused the points to appear to be overlaid on the wrong parts of the image, because the image was moving out from under the points, so to speak.

If you zoomed in far enough on the right side of the image pane, you could even see points floating over the gray 'background' of the pane, because the image gets squashed into the left side of the pane and leaves the right side empty.

This issue only affected web browsers that run on the Chromium engine, such as Google Chrome and Microsoft Edge (but not Mozilla Firefox or Safari). It was first reported on September 2019 - twice - but it would have been possible to see the issue as early as July 30, 2019.


If you used CoralNet's annotation tool to annotate any images from July 30, 2019 to June 12, 2020 (when the bug was fixed), you may have been affected by this issue. In other words, if you were annotating and didn't realize the issue was present, you may have accidentally annotated the wrong thing.

We've added some new search fields to the Browse Images page which can help you find potentially affected images:

New fields are boxed in blue.

"Last annotation date" lets you filter images based on their latest annotation activity. For example, if you annotated a particular image on December 2, 2020, then later modified the annotations on December 4, 2020, then that image's last annotation date is December 4, 2020. The date accounts for all methods of annotation, including the annotation tool, automatic classifiers, Alleviate, and importing from CSV/CPCe.

To the right of "Last annotation date", there is another field which lets you narrow the search to images last annotated by a particular method. For example, change this to "Importing" to get images which were last annotated by importing from CSV/CPCe. This would not include images which were initially annotated by importing, and then later had modifications done through the annotation tool. If you specify "Annotation Tool" in this field, another field will appear which lets you (optionally) narrow results to a particular annotator.

The "Sort by" and "Direction" fields let you change the ordering of the search results. Previously, the results were always ordered by image name, ascending.

Finally, note that the existing "Date filter" was renamed to "Photo date", to differentiate it from the new "Last annotation date" field.

To demonstrate how these new search fields can be used, here is a procedure to double check ALL images potentially affected by the zoom-in issue:

To give an example for (8) above: if you are going in ascending-date order and the current image's annotation date is 2019-11-01, then next time you can do your step (1) search from 2019-11-01 to 2020-06-12 to continue where you left off.

Note that you may be able to narrow down your search greatly if you remember some details of how you annotated these images. For example, you can narrow down results to a specific annotator (see (2) above) if you know that some annotators used Chrome and some used Firefox. Or, if you remember that you were made aware of the zoom-in issue on September 10, 2019 and were careful to avoid the issue afterwards, then you can narrow your search to only include images last annotated from July 30, 2019 to September 10, 2019.

We hope the new search fields can be useful for more general purposes, too. For example, if you sort your source's images by last annotation date, descending, you can check the images which had their annotations updated most recently. Or, you can combine this sorting scheme with a filter that gives you results from a particular annotator, if you want to check that annotator's recent work.

Image orientation issue

A recap of the issue:


Some photo files have a piece of metadata which tells the display software (web browser, desktop image viewer, etc.) which direction to orient the photo. This piece of metadata is known as EXIF orientation.

If an image specified an EXIF orientation value, the image would be rotated accordingly in the annotation tool, but the points would stay in their un-rotated positions. This meant the points weren't overlaid over the correct parts of the image. Also, if the rotation was 90 degrees, the image could get stuck on the left side of the image pane and leave blank gray space on the right side.

This issue started off only affecting certain browsers, but eventually ended up in all modern browsers including Mozilla Firefox. It was first reported on April 20, 2020, but could have been seen as early as March 24 in Apple's Safari browser, and April 7 in Chrome or Edge. Starting June 2, Firefox was affected as well.


If you used CoralNet's annotation tool to annotate EXIF-rotated images from March 24, 2020 to June 12, 2020 (when the bug was fixed), you may have been affected by this issue.

In total, there are only 19 potentially affected sources on the site. Here are the potentially affected sources' IDs: 338, 371, 1052, 1312, 1505, 1572, 1607, 1646, 1657, 1751, 1776, 1787, 1814, 1815, 1841, 1860, 1899, 1947, 1951

To check your source's ID, go to your source's home page and look for the number in that page's URL. For example, here, the source ID is 23:

If you own any of the above sources and would like to double-check your images, I can send you details of the images that were potentially affected. Please reply (privately if you like) to my Google Group forum post here so I can get back to you: https://groups.google.com/g/coralnet-users/c/_cyZvmRA28c

We apologize for the delayed follow-up on these issues and any inconvenience this may have caused.

More news to come soon

In an earlier blog post, we briefly talked about a major feature milestone we were working towards. The first part was the API - launched in September - and the second part is an improved computer vision system, which we're hoping to launch in the next week or so.

We had previously dubbed this feature milestone as 'Beta 2', but now we're actually planning to drop the 'Beta' tag entirely, graduating from CoralNet Beta to just CoralNet. We still have quite a few ideas for future improvements and features to the site, but CoralNet has come a long way after 9 years, so it seems like about time to just call it CoralNet!

We'll be talking more about the computer vision updates soon, so keep an eye out for our next post.

You can discuss this article on the forum: https://groups.google.com/g/coralnet-users/c/_cyZvmRA28c