Raphael Vector Overlays for Seadragon AJAX

In the YUMA Map Annotation Tool, we're using OpenLayers as our display frontend for viewing high-resolution zoomable images. For a while, I've been playing around with the Seadragon AJAX viewer (aka Seajax), as a possible future alternative.

One 'issue' with OpenLayers in our case is that it's a full-fledge Web GIS environment. Using it as an image viewer is really a bit of a mis-use; and since we've never gotten around to creating an optimized OpenLayers build for our purposes, it also means the YUMA Map Annotation Tool comes with an estimated 500kBytes of JavaScript code that's never used.

Seajax, on the other hand, is less than 50kBytes in size. It's superior in terms of eye candy - with smooth, stepless zooming and a neat inertia effect when panning - and it (optionally) works in conjunction with Microsoft's zoom.it image hosting service. The Seajax API also supports 'map marker'-style icon overlays and rectangle overlays that can be styled via CSS.

The one thing that has been sadly missing from Seajax, however, was free-form vector overlays. I've been doing work with the Raphael vector drawing & animation library previously. Since I thought Raphael would make an excellent complement to Seajax, I thought I'd give it a try and see if they can be combined.

Turns out: they can! With a little tinkering, it's possible to attach Raphael drawing canvases to the Seajax viewer, and scale them smoothly as the viewer zooms.



I started to wrap my experiments into a little utility library. Not quite ready for prime time just yet, but usable enough in case you want to give it a try. Code and instructions are on github; an online demo (which I'll keep updating) is embedded above.

Tweet

Spain and Portugal, 1865

And another map salvaged from the 1865 edition of E. von Sydow's school atlas found at Grandma's house. (Another one is here.) This one has a total resolution 20.007 x 17.225 pixel (that's a whopping 344 Megapixel for all you digital photographers out there) and is embedded as a zoomable Web image below in full glory.

This time I also added a link to open the map in our YUMA Map Annotation Tool. So if you feel like adding a note to this map - and are adventurous enough to test drive a VERY beta (but fabulous) tool coming fresh out of the research lab, with absolutely no documentation whatsoever (well... there is some here) - give it at try! (And let me know!)

Add an Annotation with YUMA
View Full Screen

Tweet

The Alps, E. von Sydow's School Atlas, 1865

One of several maps found at my Grandmother's house. The maps are from various school atlases from between 1850 and 1890. The books themselves were mostly gone, with only a few loose pages remaining. The map below, though, is from one where title and index pages are still preserved: E. von Sydow's Schulatlas, 17th Edition, 1865.

The map image is zoomable (try clicking on it!) and has a total resolution of 23.569 x 15.801 pixels. You can use the '+' and '-' keys (or your mousewheel) to zoom in and out, and arrow keys (or mouse) to pan.

View Full Screen

I scanned some of the maps with a flatbed scanner at 2400dpi resolution, turned them into zoomable Web images with our excellent open source tool MagickTiler, and used the OpenZoom viewer to embed them here. The maps have meanwhile found new permant residence in an acid-free cardboard box wrapped in archive-grade polypropylene envelopes.

Thanks go out to Publishers Ernst Klett Verlag GmbH for allowing me to use the maps from this atlas on my blog!

Tweet

The COMPASS Crowdsourcing Experiment IS ON!

We've now opened up full access to our small crowdsourcing experiment: the COMPASS Map Labeler. The experiment is part of a study we are conducting within the scope of the EuropeanaConnect project. The goal is to investigate the effect of social tagging and end-user map annotation on search & retrieval in online map portals, and eventually build a 'ground truth' for the evaluation of map search engines.

In our experiment we are asking volunteers to judge the relevance of a particular text label (pre-selected automatically by our system) to a random map from a test collection (kindly provided by the US Library of Congress, and mass-tiled using our very own MagickTiler). Users can also add their own labels to the maps if they see fit.

The task is simple, quick, and it's actually fun, too! (And, by the way, also a nice way to discover some hidden gems in the LoC's map collection!) So in case you want to join - head over to our study portal right now, sign up for an account, and get started!

http://compass.cs.univie.ac.at/

There's also a second stage in our experiment. It will be about map annotation, will open very soon, and I'll cover it in one of the next posts. You can already catch a first glimpse of it here, though.

Tweet