The limitations of text-based searching are well-documented; suffice to say that the usefulness of text searching of fundamentally graphic resources, even when these resources are thoroughly described, can leave much to be desired.
Maps are especially afflicted by the usual modes of encoding in DAM systems. The spatial description that they commonly receive is inadequate in many circumstances, and usually allows only for a narrow range of finding methods, such as vocabulary browsing and text search. Although cataloged maps may be related by controlled vocabulary terms, they are still removed them from their spatial context, making visualization and/or retrieval of them on the basis of land coverage - as opposed to land coverage vernacular, which is decidedly not the same thing - difficult or impossible.
All lingual description, controlled or not, is inherently subjective. In some cases, this subjectivity is useful and desirable. In others, it is an impediment to retrieval. In these latter cases, it is necessary to supplement traditional description with more objective description, one type of which is spatial description. Place names and terms can be argued over, but map coordinate coverages cannot.
The purpose of ISIS, then, is to supplement traditional map retrieval systems by reassembling maps' spatial relationships. Leave your keyboard at home!
- Compatible with a variety of different browsers including Firefox 1.5+, Safari 3.0+, and Internet Explorer 6+ (with the Adobe SVG Viewer plugin).
- Can be configured to search any Internet-accessible CONTENTdm® collection(s) that have OAI-PMH enabled - including those of other institutions. It can even search any combination of them simultaneously. Search results can be grouped by collection or mixed in aggregate, according to user preference.
- Because it can search the CONTENTdm collections of other institutions, it does not require a local CONTENTdm® installation. ISIS hosts may choose to reference only external CONTENTdm® collections and need not be CONTENTdm® users themselves.
- HTML/CSS interface templates can be customized independently of the main program code.
- No supporting software is necessary on the server. If an RDBMS (MySQL or PostgreSQL) is not available, an XML file data store can be used instead.
- Fully-featured supplementary control panel for managing and exporting spatial metadata in CSV, tab-delimited, SQL, SVG, and XML formats.
How does it work?
The selection rectangle in the main map view captures a set of spatial extent coordinates from the user. This data is inserted into a query (either SQL or XPath depending on the data store) which performs a search for maps within, partially within, or outside these coordinates, as chosen by the user. Metadata for the result set is retrieved on-the-fly from one or more CONTENTdm® servers via OAI-PMH.
The database schema stores bounding coordinates along with a pointer ("CISOPTR") and parent collection alias ("CISOROOT"), which together form a unique key. Collection definitions include the collections' names, home pages (if available), and enough information about their CONTENTdm® server URLs and paths to be able to retrieve the map metadata and link to the maps' item records. Because item metadata from CONTENTdm® is not duplicated in the spatial database, there is very little data redundancy, which prevents synchronization hassles.
If you see the UNLV logo below, your browser supports SVG well enough to be able to use ISIS.
If you are really lucky, you will see it rotating while casting a shadow and changing color as you move your mouse over it. If you don't see any of this, it means your browser doesn't support it yet - but that's OK.
ISIS aspires to conform to web standards, not to a particular browser. However, because web browsers themselves do not yet perfectly conform to web standards, some nonstandard workarounds in the system have been necessary to improve browser compatibility.
- Safari 3.0 and above on Windows and Mac offer the best compatibility and performance with ISIS as of March 2008.
- Internet Explorer 6.0 and 7.0 work well with ISIS through the use of the Adobe SVG Viewer plugin. Microsoft has not yet added native support to IE as of the version 8 beta, and the ASV3 plugin in this browser has not been tested.
- Firefox 1.5 and above support ISIS. Firefox 3 has greatly improved SVG support, and is highly recommended over earlier versions.
- Other browsers may also work, but are untested.
- You will have to supply your own unprojected geodata in raster (JPEG/GIF/PNG) or SVG format, and scale and align it properly within the viewport. This is probably the hardest part.
- If you don't already have bounding coordinates for your maps, you will have to acquire them. You will find a basic understanding of cartographic principles helpful, as you will need to know how to to take coordinates from whatever maps you wish to include in the system and convert them to a decimal-based coordinate system (such as decimal degrees). This is not always as easy as it would seem. More information is available in the user's manual.
- Basic knowledge of HTML/CSS would be helpful for customizations. HTML templates are mostly separate from the rest of the system and can be modified easily.
ISIS does not need to be hosted on the same server as CONTENTdm®, but whatever it is installed on will need to be running PHP 5.2.
- ISIS relies on OAI-PMH to retrieve item metadata for the results list. If OAI has been disabled on a CONTENTdm® server that ISIS is referencing, no metadata will appear for any of the maps from that server. (The item thumbnails will still appear and link properly to the item records, however.)
- ISIS uses an equirectangular projection, which maps latitude/longitude coordinates to screen X/Y coordinates. There can be a lot of distortion in this projection depending on scale and distance from the poles.
- Maps with non-decimal coordinate systems are not supported. (Note that most coordinate systems can be converted to decimal.)
- Map coordinates can be stored in any decimal units, but all coordinates of all maps in the database must be in the same units.
- Non-rectangular maps have to be represented as rectangular.
- Practically speaking, polar maps are not supported.
- Non-orthographic maps are not supported - i.e. the maps' latitude and longitude lines must be parallel to the maps' edges so that the view to the surface is straight down (unless, again, orthographic representations of them are acceptable).
- There is no support for fancy geodatabases etc. The main focus is on developing something simple that can be deployed by non-GIS experts without requiring special software infrastructure.
ISIS is open-source software originally developed at the University of Nevada, Las Vegas Libraries. It is no longer being developed or maintained. The project source code, to-do list, and downloadable distributions will remain hosted on Google Code.
The user's manual is available on the ISIS Google Code project page, in the wiki.
For questions related to ISIS or anything else involving digital collections at UNLV, please contact us.
- Alex Dolski, Web & Digitization Application Developer
- Brian Egan, Web Multimedia Designer
- Cory Lampert, Digital Projects Librarian
- Kee Choi, Web Technical Support Manager
ISIS is Copyright © 2008 Board of Regents of the Nevada System of Higher Education, on behalf of the University of Nevada, Las Vegas. ISIS is available under the terms of the BSD License, except where otherwise indicated. See the file COPYING included in the software distribution for the full text of this license.