Image Exif information viewing/GPS location information editing tool | ZeroTools

Exif is metadata often stored in the APP1 segment within JPEG files. This tool reads the selected JPEG as a data URL using FileReader, and parses the Exif area using piexifjs.

On the page, the 0th IFD's DateTime, camera Make, camera Model, Software, and GPS latitude and longitude are populated into the form.

It does not post the image itself to ZeroTools' conversion servers for analysis.

Metadata contains various information such as manufacturer-specific items, thumbnails, multiple IFDs, and XMP, and this screen cannot edit all of them.

"Items not displayed do not exist" is not necessarily true, and areas not handled by piexifjs may remain after saving. If a full survey of all items is required, use specialized software suited to your purpose, such as ExifTool.

In the form, you can check and modify DateTime, camera Make, camera Model, Software, and GPS latitude and longitude. There are no individual fields to edit lens model, photographer name, copyright notice, image description, or DateTimeOriginal.

Leaving DateTime, Make, Model, or Software blank does not result in a process that individually deletes the existing tags; it only overwrites items with values.

For GPS, if either latitude or longitude cannot be entered as a valid pair of numbers, the corresponding coordinate tags are deleted.

The shooting date and time is not the file system creation date and time, but the date and time tag within the Exif. The date and time referenced by photo management apps varies by app, and they may use tags other than DateTimeOriginal or the file modification date and time.

To see if the editing results are reflected in your target app, load the saved JPEG back into that app to verify.

GPS can be entered as decimal latitude and longitude. Latitude is roughly in the range of -90 to 90, and longitude is -180 to 180, where North latitude and East longitude are positive, and South latitude and West longitude are negative.

When saving to Exif, the decimals are converted to rational numbers of degrees, minutes, and seconds, and the signs are recorded as reference values of N, S, E, and W.

By opening the map check link next to the input fields, you can pass the coordinates to a map service and check the location. Because coordinates are sent to an external map service in this operation, do not open the link for location information you do not want to make public; verify it using numbers only.

Pay attention to mixed up latitude and longitude, forgotten minus signs, or positional shifts due to rounding, and reload after saving to check the values.

When you save your edits, the tool constructs Exif data from the form's values and downloads a new file with it inserted into the JPEG's Exif area.

It is not a process that draws the image onto a canvas and recompresses it as a JPEG. Therefore, it is not a tool intended to recompress pixels, but it cannot be described as "every byte of the file is perfectly identical except for Exif." The file size and internal arrangement will change due to the reconstruction of the Exif area.

Altering or deleting the Orientation tag may change the orientation on viewers. Also, the handling of unedited metadata and embedded thumbnails depends on the library.

Before sorting the original, verify that the saved file can be opened, that the orientation and colors are as expected, and that necessary tags remain.

If you want to delete only GPS and keep other Exif data, save with the latitude and longitude fields left blank in this tool. Individual editing is also suitable if you want to overwrite the 0th IFD's DateTime, Make, Model, or Software.

On the other hand, if you want to remove the entire Exif area handled by piexifjs from a public copy all at once, use the "Delete all Exif" operation on the screen or the Exif deletion and metadata cleaner.

However, neither tool will erase addresses, faces, name tags, or vehicle numbers captured in the image. Also, the "Delete all" feature of this tool is an operation targeting the Exif area handled by piexifjs, and does not mean guaranteed erasure of all additional information that could exist in the image format.

Please recheck with another viewing method before publishing, and perform cropping or blurring as necessary.

First, prepare a duplicate of the original, and load the duplicate into the tool. Note the read values, edit only the necessary items, and save.

Loading the saved file back into this tool allows you to at least check how the items supported by this tool were recorded. Furthermore, check the orientation, date and time, and location information in the preview of the photo management software or posting destination you will actually use.

The supported format is JPEG. Selecting PNG, HEIC, WebP, or RAW will not be treated as input for Exif editing. Do not simply change the extension to .jpg; perform proper image conversion if necessary.

Large files use a lot of browser memory, so if processing fails, close other tabs or consider desktop Exif editing software.

Being able to edit within the browser reduces the opportunities to hand over the processing target to external services, but it does not automatically guarantee security.

Manage the shared device's download history, cloud-synced storage locations, backups, and methods for sending edited files. Opening a map link sends coordinates externally, but editing coordinates in this component does not.

For photos where the camera clock was off, correcting the Exif shooting date and time to the correct time can improve the sorting in photo management software.

However, this tool edits values one by one, and is not a batch correction feature that adds or subtracts a fixed amount of time across multiple images.

For large numbers of photos from an overseas trip where only the time zone is shifted, dedicated software supporting batch shifting is more efficient.

Common Exif date and time expressions may not include time zones, and "2026:09:29 14:30:00" alone cannot uniquely determine whether it is Japan time or local time.

It is also distinct from the file modification date and time or the date and time uploaded to the cloud. When modifying for organization purposes, cross-reference with travel itineraries or other photos, determine the meaning, and then edit.

For evidentiary photos or record materials, the practice of not altering the original metadata and annotating a duplicate is appropriate.

Manufacturer names and camera model names are sometimes used for searches or equipment-based organization in photo management software.

Unifying the notation improves scannability, but changing it to a non-existent equipment name does not prove that the image was taken with that equipment.

This is because Exif is editable information and not a signature guaranteeing authenticity. The Software field is also just a string recording the name of the creation or editing software, and is not an audit log for verifying actual processing history.

This tool does not have individual edit fields for copyright notices, photographer names, lens names, or image descriptions. If they are included in the existing Exif, a normal save may leave them in the loaded Exif object.

If you want to remove unnecessary information in bulk before publishing, do not judge only by looking at the individual fields; use the bulk Exif deletion and re-inspect after saving.

Even if rights notices are important, do not assume they can be added with this tool, but combine compatible software, notation on public pages, contracts, watermarks, and original management.

Latitude and longitude appear different in degree-minute-second notation and decimal notation. For example, 35 degrees 30 minutes is 35.5 degrees, not 35.30 degrees.

The input fields of this tool assume decimal numbers. When transcribing from maps or other materials, verify the notation format.

North latitude and East longitude are positive, South latitude and West longitude are negative, and near Tokyo, the order is approximately latitude 35, longitude 139.

Roughly rounding coordinates can blur the location, but how many digits to drop depends on the purpose and surrounding environment.

Even if you only intend to leave it at the municipality level, it might still be pinpointed in combination with other photos or background information.

If exact locations are unnecessary for public photos, deleting the GPS fields is less likely to cause misunderstandings than rewriting them to another location.

If the location is needed for business records, follow management regulations without arbitrarily rounding.

A file with altered Exif is not the same file as the original, even if pixel recompression was not performed. The hash value also changes.

When originality is critical for audits, reporting, research, insurance, construction records, etc., place the unedited file in a read-only storage location, record its hash value and acquisition path, and manage the edited version under a different name.

For public copies on SNS, either leave only the necessary Exif or remove target areas entirely with a cleaner. For deliverables, check requirements so as not to delete color profiles or existing rights information expected by the recipient.

Since this tool lacks fields to individually retain or edit those, use corresponding specialized software if needed. It is important not to oversimplify as "the more retained, the better" or "the more deleted, the safer," but to handle only the information necessary for your purpose and inspect the processed result in its actual usage environment.

Even if a file looks like a JPEG, it cannot be loaded if its true format is HEIC or WebP and only the extension was changed. First, check the format using file information in the OS or image viewer.

Images saved from SNS or editing apps may have had their Exif deleted from the start, in which case the editing fields will be empty.

Empty fields do not necessarily indicate a malfunction.

If downloading does not begin after pressing the save button, check your browser's automatic download restrictions, storage location permissions, and free space.

If an error occurs during loading, test the function with another JPEG to isolate whether the issue is with a specific file. There is no feature to repair corrupted JPEGs, so restore from a backup if the original cannot be opened normally.

Performing resizing, rotation, compression, or format conversion with other tools may cause Exif to be deleted, duplicated, or regenerated.

Even if you edit Exif first, the values may be lost in subsequent processing. Generally, it is clearer to check and sort metadata last on a public copy that has finished pixel editing and format conversion, and then re-inspect the final file.

However, the order changes depending on the work objective, such as sorting photos using shooting dates before batch editing. Use different names for intermediate and finished files, and verify that necessary items remain after each step.

Images once registered to cloud photo services may have dates and locations managed separately as service-side information, and altering the Exif in the JPEG later might not reflect on existing registrations.