Quick Start:

In general, follow these steps to find a particular item or set of items.

1) Select the collection that you with to search (from the lower left hand corner).
2) Position the map so that the area you wish to search is visible within the browser. You can use the zoom level chooser, the address locater, and/or drag either the main atlas or the overview map (in the lower right corner) to positon the map.
3) Once items are visible, you can adjust the size or opacity of the thumb images if necessary (this is usually only necessary for non-tiling collections such as the "apframes" collection).
4) Click on a thumb image to bring up a larger browse image that also indicates the title of the item, and includes a button (marked "show") to display download and catalog information.
5) Pressing the "show" button will allow you to choose a file for download.

Information:

The NGDA Collection Browser is a geospatial search engine for the collections of air photography, maps, and satellite imagery held at UCSB�s Map and Imagery Laboratory.

In order to faciliate the browsing of items tied to particular spot on the earth, a number of navigation features have been implemented, described below. To present the items in a useful way some design decision were made which differ from our previous Alexandria Digital Library (ADL) interface.

1) The only way to search the collections is by location, either by dragging and zooming the map, or via the address finder toolbar.
2) Only one collection may be searched at once (although it easy to switch collections).
3) Items are only visible when they fit on the screen, that is, are neither too small or too big to view.

On the other hand, after a few minutes of adjusting we hope that it is apparent that the ease of use of this interface should make up for those limitations, at least for most searches. Also be aware that, because of the number of images loading simultaneously, the browser can take up a significant amount of memory. So it is recommended that the user has a relatively fast computer and a fast internet connection. If necessary, the previous interface is still available and supported and can be found at ... Also, if you are interested in creating your own interface based on the ADL middleware, please email NGDA collection manager Greg Hajic at ....

For questions, comments, or bugs dealing in particular with this interface (as opposed to the actual collections) please email the NGDA interface designer Angus Forbes at forbes@library.ucsb.edu.

Examples         back to top

Example Search 1:

Howard, a map enthusiast, is interested in browsing the landsat satellite imagery. He clicks on "landsat mosaic" (currently our only satellite imagery collection) and sees a number of images appear over the atlas. Since this collection spans the entire world, wherever he drags new items will appear. He uses the overview map in the right hand corner to drag more quickly over China. In the upper left hand corner, a zoom widget shows that there are 49 images available at this zoom-level (level 04), and 12 images available by zooming in to level 05. Because it would be too pixelated to see the thumbnails clearly, no images are available when zooming-in past level 05. Howard can click on any of the items to see a better resolution image of that item. Additionally, information becomes available as to the title of that item, how to download the archived version of the item, and how to view the complete metadata associated with the item. However, Howard is not interested in any of this information. He simply clicks on various items, opens and closes the images, and admires the glorious shapes of our physical planet and the interesting irridescent color scheme used by the landsat satellite.

Example Search 2:

Helga, a GIS scientest, is interested in finding topographic maps for the Joshua Tree National Park in California. She clicks on "drg_24k_ca" (currently our only topographic map collection) in the lower left hand corner. She then types in Joshua Tree in the address locater (on the right hand side of the screen) and presses "find address". The map recenters on Joshua Tree and zooms into level 11. And since level 11 is an appropriate resolution for the maps in this collection, a number of maps are loaded and immediately begin tiling the screen. Helga opens a number of maps over the park and decides that for her scientific purposes she is interested in finding out more about "yucca valley north" and "joshua tree north". She clicks on "show" and is presented with a list of files available for download. For some reason she has a MrSid plug-in viewer in her browser and so clicks on the rather large MrSid file, which soon opens and enables her to view this map at a very high-resolution. Yes! This is exactly what she needed! Being a GIS scientist she is interested in the attached ESRI files, and downloads those as well.

Example Search 3:

George, an urban landscape historian, is interested in interpreting the changing environment of Southern California�s greatest metropolis, Los Angeles, as it develops throughout the last century. He clicks on our historical air photography collection, "apframes", in the lower left hand corner. By naviagting the orange "cluster bubbles" he zooms in closer to Los Angeles one click at a time, and is provided with an idea of the geographical range of this 50000 item collection. Upon reaching zoom level 12, the level at which most of photographs in this collection are available for viewing, a new widget appears in the lower left hand corner next to the collection-chooser panel. This is the flight selector panel. The inscrutably-lablelled flights are organized by the decades in which they were flown. Each sortie generally returned with quite a large number of photographs. George clicks on the earliest flight collection, c-113 from the 1920s. There must be 200 photos there! Such a bounty of primary sources! George can hardly contain his glee. Because the photos are overlapping they are difficult to see. He adjusts the "change opacity" and "change size" sliders on the lower right hand side until he has a good idea of which photos he wants to examine more thoroughly. He clicks on one and presses "show" and then presses "download TIFF image". Unfortunately, this document is restricted to the UCSB Map & Imagery Laboratory. To obtain high-resolution TIFFs for the historical air photographs please contact one of out helpful reference librarians at ....

User Interface Elements         back to top

Zoom Level Chooser:

In the top left hand corner, a menu lets you select the current zoom level. Level 03 will zoom out far enough to view entire continents, while Level 16 will zoom in close enough to see street level detail. To the immediate right of each zoom button is a number indicating how many items in the currently selected collection are contained within the current viewport at that zoom level. In addition, each zoom button is color coded to indicate the visiblity of items at a particular zoom level. If the zoom button is colored orange, then items are available to peruse at the indicated zoom level. If not, and a number to the right indicates that items are indeed contained within the current viewport, then items are hidden to avoid presenting items that are too miniscule to see or too large and pixelated to interpret.

Collection Chooser:

In the bottom left hand corner, a menu lets you select the collection to search on. The collections are divided into maps, air photography, and satellite imagery. Note that you can only search on *one* collection at a time. The current collection is colored orange.

In the case of the AP frames collection, which contains an enormous amount of air photography, the collection is further broken down into decade, and then still further by flight. The flight number may not necessarily mean anything to a human, but by simply clicking on each flight within a particular decade a managable number of items will be displayed. The current flight is colored orange. Note that because of the overlap of items even within a single flight, it is often necessary to adjust the size and/or opacity to differentiate photographs.

Address Locator:

On the top of the toolbar widget (on the lower right side of the screen) is a text field and button labelled "find address". The NGDA Collection Browser uses the Yahoo Geocoder API to map adresses onto coordinates and zoom levels. Simply type in an address and press "find address" to recenter the map on that address. The address can be a country, state, province, city, town, street, and/or national park. It is best to be as specific as possible to avoid ambiguity.

Opacity Slider:

In the middle of the toolbar widget is a slider labelled "change opacity". This slider changes the transparency of all visible item. All the way to left is completely transparent. All the way to the right is 100% opaque.

Size Slider:

On the bottom of the toolbar widget is a slider labelled "change size". This slider changes the size of all visible items. All the way to the left is 5% of the original size. All the way to the right is 100% of the original size.

Overview Map:

On the bottom right had corner is a smaller map at a further zoom level. You can use this map to navigate greater distances more quickly, or when the regular map is too cluttered by items.

Cluster Bubbbles:

If there are items within the current bounds of the visible atlas, but that would be too tiny to be useful at the current zoom level, then an orange "cluster bubble" will appear to indicate this situation. By clicking on the cluster bubble, the map recenters and zooms in closer to the earth. The size and position of the cluster bubble indicates the number and range of items at a closer zoom level to the earth. The following sequence is an example of a user navigating cluster bubbles until arriving at an appropiate zoom level for viewing (in this case a topographic map of Morro Bay, CA from the "drg_24k_ca" collection at zoom level 10). The tooltip over the cluster bubbles indicate how many items are beneath that bubble at the next zoom level. An alternative way to reach these particular maps would be to type "morro bay, ca" in to the address locater.

zoom level 05

zoom level 06

zoom level 07

zoom level 08

zoom level 09

zoom level 10