Viewing large Vera Rubin Observatory images on the browser

This is a simple app for viewing very large images released by the Vera Rubin Observatoy using DeepZoom format and associated technology.

Specifically, it is using a fork of the towa viewer which itseff is based on OpenSeaDragon (see below).

The app is deployed to Github pages and includes the First Look image here: https://andreasplesch.github.io/VeraRubinDeepZoomViewer/treasurechest.

Converting large tiff files to dzi

VIPS can convert tif format to dzi pyramids using the dzsave operation:

$ vips dzsave large.tif largePyramid.dzi

towa (WIP)

A web-based viewer for DeepZoom (.dzi) images.

towa is a web-based DeepZoom image viewer built using Vite and a fork of OpenSeaDragon that implements support for viewing on-disk DeepZoom pyramids in browsers that support the File System Access API.

Routes can be defined in routes.json to use towa to serve and display predefined DeepZoom pyramids for various purposes.

The tool itself is located at towa.dev.

Installation

Clone the repo, then

npm install

To build the site,

npm run build

and the site files will be available in dist/.

Usage

The site comes with configurable routes that can serve predefined DeepZoom pyramids. To create a route, add an object with configuration values to the routes array in routes.json.

[
  {
    "name": "duomo",
    "dziURL": "https://openseadragon.github.io/example-images/duomo/duomo.dzi",
    "filesURL": "https://openseadragon.github.io/example-images/duomo/duomo_files",
    "title": "Duomo",
    "description": "An italian cathedral."
  }
]

• name - specifies the name and route of the mosaic. It must be unique.
• dziURL - specifies the URL to the .dzi file. This can be a URL in public/. Note that the contents of public/ will be available in the root directory of the site after it is built (i.e. public/mosaics/duomo.dzi -> /mosaics/duomo.dzi).
• filesURL - (optional) specifies the URL to the _files directory. If omitted, the URL of the .dzi file will be implictly used (i.e. duomo.dzi -> duomo_files/).
• title - (optional) specifies the title of the image. This value will be used as the title of the site.
• description - (optional) gives a description of the image.

By default, the index of the site routes to the viewer tool. You can disable this by setting viewerAtIndex to false in routes.json.

URL Parameters

When viewing a predefined route, the viewer will update the URL with hash parameters containing the current focus and zoom. This can be used to link to specific locations in an image. For example, this link

https://towa.dev/duomo#/0.5972/0.2309/10.6333

will take you to focus (0.5972, 0.2309) and zoom level 10.6333 in the duomo image.

License

MIT

Acknowledgements

Inspired by osd-dzi-viewer.