The purpose of tagging is to let people mark and find specific content in images. Tags can apply to both whole images and objects in images. You can, for instance, search for images depicting forest, city, or construction, or images that have fire hydrants, waste baskets, or bicycle racks in them. The precondition is that someone has added the tag, so the more you add, the more you and others will benefit from it.
When you browse images on the Mapillary web, you’ll notice a tag icon at the right-hand side. This icon shows you whether the current image has any tags. If yes, a little green dot together with a number will be displayed on that icon, denoting how many tags the image carries. If you click on the icon, you’ll see the tags listed. If you click on the listed tag, you’ll see the details for it.
Tags are one of the two types:
If the image has object tags, you will see these as green dots on the image. Hover over them to see the label for the tag and the bounding box that’s been drawn around the object. If you click on the green dot, a window with the tag details pops up, where you can also see who added it.
To search for tags on the map, start by clicking on the tag search icon at the top of the web app to turn tags on.
You will enter the tag view where every image that’s carrying a tag is depicted as a yellow dot on the map. You’ll need to zoom in (to level 14 and above) to be able to click on the dots and open the respective image.
Using the search box that you access by clicking on the tag icon, you can narrow down which tags get displayed. As you start typing, an autocomplete function will suggest tag labels, so you can find the content you are interested in. Keep in mind that for some tags, it might be the case that no one has added them yet, in which case the search will not give any yellow dots on the map.
To submit tags, select the little tag icon on the right when viewing an image on the Mapillary web, and then ‘Edit tags’. You will enter the tag editor mode where you can add two types of tags:
To start with, select the label for the tag you want to add. Start typing in the ‘Search tags’ box and an autocomplete function will suggest labels that you can choose from. The list is based on a selection compatible with OpenStreetMap. For the time being, you can’t add custom labels.
Once you’ve found your label, you can either use the ‘Add image tag’ button to add it to the whole image or draw a bounding box on the image to add this label to an object tag.
When you’ve added a tag, the previously selected label will remain active so you can add more of the same tag, whether to the same image or another image you move to via the navigation arrows. If you want to switch to another label, just return to the search box to leave the current one and select another.
You draw bounding boxes around objects by dragging them on the image with your mouse. When you release the mouse, you’ll see two icons appear next to the box. Click on the green tick to confirm and submit the tag (you’ll see it appear at the left of the image). If you don’t want to submit this tag, click on the red icon with the cross to cancel.
If you want to pan around the image, hold down Ctrl while you drag. You can zoom in by using the mouse scroll to see more detail. By default, navigation arrows are displayed in the image so that you could easily move between different images to tag—you can toggle them on and off by pressing Shift.
You’ll see all the tags of the current image at the bottom left of your view. Clicking on a label will display the information on the tag. If the tag has been created by you, the details window will also display a ‘Delete’ button so you can delete the tag. If you want to modify any of your tags, you need to delete the original one and just add a new one.