Easter rolls around early this year and the MIX08 Deep Zoom announcement made it just in time to try some experiments in the Easter Egg tradition. Using Deep Zoom Composer, images can be inserted at various locations within the zoom pyramid. This means full images of documents, html pages, schematics, data records, photos … can be inserted down at lower levels of a main image’s zoom. This was pointed out in Laurence Moroney’s recent blog posting, which showed an image inserted into the pupil of an eye in a framing picture. Looking at potential for this type of DeepZoom, here is an experiment from a geospatial perspective.
The SparseImageSceneGraph.xml generated by Deep Zoom Composer shows how position and insert scale are part of a SceneNode Element:
This brings to mind the various easter egg items available in well known software packages. Interestingly aerial imagery lends itself to this type of feature since the spatial dimension provides a handy reference for hanging additional information.
As an experiment I’ve updated a Denver USGS Urban Area imagery tile with some easter egg information in the Deep Zoom approach. In this case zooming into Coors Field you will notice some small patches scattered around the field. Behind home plate are a couple of informational items from the Colorado Rockies Home page, including a roster list. Then panning around the field you will see various player cards at their field positions.
In each of these cases the image is available at sufficient scale to read the text. The scene graph will allow multiple depth image insertion, so I could go further hiding some detail of a player life inside a dot on an individual player card.
Fig 2 – Zoomed in to see the location of additional SceneNode images
Fig 3 – Zooming further you can read the text and view additional information embedded in the map
Fig 4 – Finally zoomed to an individual player card at short stop.
So far I can see this as little more than a novelty, but perhaps it would have some uses. For example a sitemap builder could be enhanced to output a Deep Zoom image to allow moving around a multipage graph showing every page in a site. This type of tool would be a great way to QC a static html site (are there any of these still around?). Perhaps facility management would benefit as well, since personnel records could be associated with a desk inside an office, inside a building floor, inside an office campus giving a secondary spatial way to review office space. Adding some papers to the desktop and then sending a deepzoom link with the apropriate zoom factor might be a novel approach to document workflow management:
public void ZoomAboutLogicalPoint( double zoomIncrementFactor, double zoomCenterLogicalX, double zoomCenterLogicalY )
In telecom, outside plant items such as transformers and switches could contain schematics embedded within a snapshot of the item, which is itself embedded in a wide area schematic or aerial imagery showing a city wide sector.
The next trick is to find a way to back track through a Deep Zoom Scene graph to a real world coordinate. This seems possible using the pair of methods shown in the MultiScaleImage class:
Once a coordinate has been reversed into its outer root element coordinates, it should be possible to assign a real world georeference, which would be used for a nearest query on a PostGIS table for obtaining additional attributes or accessing live data.
Which brings up the big problem I see to date on the DeepZoom technology: it is static. The processing of large image sets into pyramids is not fast. Although there are some tantalizing command line hints in the ImageTool.exe and SparseImageTool.exe packaged with Deep Zoom Composer there is no real documentation:
usage: ImageTool [-v]
-v enable verbose outputcommands:
Converts an image or a dir with files to a Seadragon stored image.
The optional outdir parameter specifies the output directory path.
The optional basename parameter allows overriding the output filesename
which defaults to the basename of the input file.
The default form is single-file (not exploded).
Specify large to use a slower algorithm, but one that can process very large images.
The default format is HDPhoto (wdp).
The quality value should be a number in the interval [0.0-1.0]. Default is 0.8
A quality value of 1.0 will result in lossless compression if possible in the chosen format.
If not specified, tilesize values default to size of 255 and a physical size of 256.
Legal values for tilesize values are >= 64 and <= 2048.dump
Dumps info about the specified Seadragon stored image file.
Extract level image into specified output directory in
TIFF format. If level is not specified, all are output.
If the output directory is not specified, files are written to
the current working directory.
The possibility of adding smaller items to an already existing large pyramid holds promise for more dynamic real time updating from a content management system.
In looking at the pyramid of jpg files it seems possible to add a simple place holder of the right dimension and then change content by overwriting the already existing pyramid jpgs with updated content. In this way easter egg content with relatively small jpg sets could be updated dynamically out of a content management system on each refresh. If Microsoft SeaDragon adds MultiScaleImage elements to WPF xaml some of the static issues surrounding DeepZoom viewing might be easier to handle.