Understanding Mapillary sequences & their symbology

What is a sequence?

A sequence refers to a series of images captured and then uploaded to Mapillary based on the time and place of capture. Sequences can be up to 1,000 images long. 

When you upload imagery your images will be split into sequences based on capture time. 

When you explore images on Mapillary’s web or mobile apps, we use sequences to structure the viewing experience. Each image, in addition to a unique image key, has a sequence key that links it together with other images in the same sequence. 

Why do we group images into sequences?

We prefer sequences instead of single images because we are building a 3D reconstruction of the world with our computer vision technology, and to that end, it is important to have lots of overlapping images of the same place. This is exactly what you achieve with capturing images in sequences.

If you capture just one image and upload, it will be a sequence by itself. If you capture 2000 images in one capture session, and upload them all together, it will be split it into two sequences.

Regardless of the images being grouped into sequences, they are still all interconnected on Mapillary. You are able to navigate around both within and between sequences by using the playback arrows at the top of the image viewer or the spatial arrows overlaid on the image, respectively.

Understanding sequence symbology

• Mapillary Coverage: Uploaded and processed sequences are shown in green color on the Mapillary Web App.

• Your coverage: Your own uploaded and processed sequences Mapillary coverage are shown in blue color on the Mapillary Web App.

• Selected sequence:  A selected sequence is shown in turquoise color on the Mapillary Web App.

• Partially Processed Sequence: Partially  processed sequences are shown as white dots with a light blue border on the Mapillary web app. If the sequence is in this state, previewing your imagery is possible, however processing is not completed yet and the sequence will not be part of Mapillary map coverage tiles. You can step through the sequence in time, but spatial navigation and image transitions are not available yet.