eScience @ Microsoft : Virtual Earth

SciScope app and code available for download

eScience — Thu, 16 Jul 2009 02:47:08 GMT

Earlier today the code behind the SciScope site was made available at SciScope.CodePlex.com. This enables others to make their datasets/repositories available and allow others to discover, download and utilize their data in a simple to use website. Also the semantic support is quite useful in finding related data.

SciScope Project Description

SciScope (see it live) is a prototype web application that allows data discovery from across multiple distributed heterogeneous data repositories. It leverages Bing Maps (formerly Microsoft Virtual Earth) and Microsoft SQL Server 2008 to support queries involving spatial, temporal and thematic constraints over an index of sensors operated by agencies such as USGS, EPA and NOAA as well as user provided data. SciScope leverages taxonomies stored as triples in SQL Server to provide search suggestions and for dealing with semantic heterogeneity between different data repositories.

_{SciScope screenshots (discovering/downloading insecticide data, browsing ecoregions left to right) for video tutorials click here}
This CodePlex release includes some desktop tools to simplify data publishing and content crawling for SciScope namely Catalog Publisher and Catalog Updater.

SciScope - Home

Cross Posted from Dan Fay's Blog (http://blogs.msdn.com/dan_fay)

The Earth, Stars, and Planets in 3D

eScience — Tue, 27 Jan 2009 22:20:10 GMT

One of the coolest new features of the WWT Solstice Borealis Beta (released at the beginning of Jan) is the ability to see the Earth, Stars, and Planets in a stereoscopic 3D effect. I’ve been using the Anaglyph mode (View | {arrow} | Stereo | Anaglyph) which uses the stylish red/cyan glasses shown below to not only look at the Stars, but you can zoom all the way out and see the lattice structure made up galaxies of the universe. Checking out the planets, like Mars, Saturn, etc is also very impressive. Going down to Earth, you can change your perspective by holding down the ctrl key and then you can fly into objects like Mount St. Helens

Mount St. Helens in normal view Mount St. Helens in stereoscopic view

Check it out if you have a pair of red/cyan glasses – they are all the rage :-)

Cross Posted from Dan Fay's Blog (http://blogs.msdn.com/dan_fay)

Virtual Earth in full view

eScience — Tue, 28 Oct 2008 23:01:25 GMT

Now this is a way to view Virtual Earth – talk about an immersive experience. I would like to see how WorldWide Telescope would look on this display…

PDC2008 ShowOff Entry: Multi-channel Virtual Earth
Multi-channel Virtual Earth
Description
This video shows a multi-channel version of the Virtual Earth control running on a custom curved screen that provides a 180 degree horizontal field of view. The screen is created using eight high-end full 1080p projectors with a professional warping and blending system. The code is a modified version of a sample project with a custom camera class to properly adjust the FOV and camera offset for each projector and some code to synchronize the camera position across the network. The system is being controlled with a wireless Xbox 360 controller.

PDC2008 ShowOff Entry: Multi-channel Virtual Earth | briankel | Channel 9

Cross Posted from Dan Fay's Blog (http://blogs.msdn.com/dan_fay)

Overlaying images on Virtual Earth without tiling

eScience — Mon, 28 Jul 2008 20:02:00 GMT

One thing a lot of people complain about web mapping applications is having to create tiles to be able to overlay images as new map layers. Tiling is boring, time consuming and pointless if all you have is a 100 KB image (not images of different details for different zoom levels) with no noticeable distorted look due to projection difference. It is a serious time sink when you need to create them on the fly (creating tiles from an image generated by an application that uses real-time data). And what if you want to overlay an animation? For my case, I create the images programmatically and re-project them during the process if necessary. So I skipped the tiling part and below is how I did it, should you want to do it as well.

Let's start with just putting the image on top of the map in which case we'll be adding the following line in the body of the document. Here the assumption is that the map has a z-index less than 1000.

<img src="myimage.gif" id="overlay" style="z-index:1000; opacity: 0.7; filter: alpha(opacity=70);position:absolute;left:20px;top:20px"/>

Here left, top values are completely arbitrary. Below you can see how the image can be positioned properly. originalHeight and originalWidth are the dimensions of your image in pixels. Latitude and longitude are in decimal degrees.

var imageUpperLeftCornerLatitude = 42.335; var imageUpperLeftCornerLongitude = -112.6791; var originalHeight = 300; var originalWidth = 296; var imageLatLon = map.LatLongToPixel(new VELatLong(imageUpperLeftCornerLatitude, imageUpperLeftCornerLongitude)); var imageOverlay = document.getElementById('overlay'); imageOverlay.style.top = imageLatLon.y; imageOverlay.style.left = imageLatLon.x;

At this point, the image doesn't respond to zoom/pan events. And the worst news is, once you move your mouse over the image, you're no longer interacting with the map.

This issue can be solved by making the overlay a part of VELayerListDiv.

var VElyrs = document.getElementById('VELayerListDiv'); var imageOverlay = document.getElementById('overlay'); VElyrs.appendChild(imageOverlay);

Once you add this, you will see that the overlay responds to 'pan event' the same way a tile layer does. However 'zoom' doesn't work the way it's supposed to. So we need to write a custom function to handle the zoom event. You will also notice that position is adjusted, as well.

function RedrawImage(){ var imageOverlay = document.getElementById('overlay'); var currentZoomLevel = map.GetZoomLevel(); imageOverlay.width = Math.round(originalWidth*(Math.pow(2,(currentZoomLevel-imageZoomLevel)))); imageOverlay.height = Math.round(originalHeight*(Math.pow(2,(currentZoomLevel-imageZoomLevel)))); var imageLatLon = map.LatLongToPixel(new VELatLong(imageUpperLeftCornerLatitude, imageUpperLeftCornerLongitude)); imageOverlay.style.top = imageLatLon.y; imageOverlay.style.left = imageLatLon.x; }

You can see that the image is resized using a function based on the difference between the map zoom level and 'imageZoomLevel'. ImageZoomLevel is the zoom level at which a pixel in the image corresponds to a pixel on the Virtual Earth map. In other words if you're dealing with a satellite image or numerical model output with a grid size of 5 kilometers, the zoom level at which a pixel on the Virtual Earth map corresponds to 5 kilometers is the ImageZoomLevel (which doesn't have to be an integer). Ground resolution (meters per pixel) at a given latitude and zoom level can be calculated using the following function where 6378137 meters is earth's radius.

Ground resolution = (cos(latitude * pi/180) * 2 * pi * 6378137 meters) / (256 * 2 ^{zoom level})

Especially if you're programmatically re-projecting your image to Mercator, you can use a random latitude in this function. Otherwise I'd assume that you don't mind a little distortion (and your image is not close to the poles). Now we can attach the event to RedrawImage function. (This needs to be done when you initiate the map.)

map.AttachEvent('onendzoom', RedrawImage);

However, the zoom event still doesn't look very smooth. A show/hide while resizing takes place can fix this.

map.AttachEvent('onstartzoom', HideImage);

Where HideImage would do the following

imageOverlay.style.visibility='hidden';

which requires an update on the RedrawImage method so that the image is visible again after the transformation.

imageOverlay.style.visibility='visible';

And there you have it. This way you can overlay animated GIFs, tables, iframes .... i.e. almost anything. Let's hope that VE API natively supports this in future releases.

Original posting

DeepEarth - VE and Silverlight Deep Zoom

eScience — Thu, 19 Jun 2008 00:09:17 GMT

Just ran across he DeepEarth OpenSource community project on CodePlex - bringing SilverLight 2 Deep Zoom to Virtual Earth - it pans and zooms really smooth. Test it out or check out the video

Cross Posted from Dan Fay's Blog (http://blogs.msdn.com/dan_fay)