Dynamic Drought Index Maps
A web application for dynamic drought index maps in North and
South Carolina has been developed as a web-based spatial decision
support system for water resource planning and management.
It consists of three parts: a numerical model for calculating
percentiles of each drought index and performing spatial
interpolation and averaging; a database storing the results from
the numerical model, and a graphical user interface developed using
Scalable Vector Graphics (SVG) with server-side scripting language
The graphical user interface provides user options for a selection
of drought indices, their percentages for blending, and the
classification method as well as resultant maps, graphs, and
tables. It shows the advantages of flexibility in the interface.
Individual drought measures have been computed and interpolated at
a 4 km resolution in North and South Carolina for the period
January 1950 to present. Using this application the user can map
or extract daily (for only KBDI), weekly, and monthly values
for individual or blended drought indices. Since the indices are
computed for point locations and then interpolated to a grid, the
index values can be spatially aggregated based on the user
specifications such as states, counties, climate divisions,
2-8 digit hydrologic units, and watersheds of interests.
Scalable Vector Graphics
The Scalable Vector Graphic (SVG) has recently gained lots of
attention for web-based dynamic display of cartographic maps.
The Scalable Vector Graphics (SVG) defines vector-based graphics in
eXtensible Markup Language (XML) format for the web.
It is a World Wide Web Consortium (W3C) recommendation and can be
integrated with other W3C standards such as
Document Object Model (DOM). DOM is a platform and language neutral
Application Programming Interface (API) that allows programs to
access and update the content, structure, and style of a document.
The use of server side script language such as PHP and client side
script language such as ECMAScript enables the communication
between the database and SVG elements through the DOM.
This website is optimized for Microsoft Internet Explorer 5 and above.
Adobe SVG viewer plugin is needed to see
SVG maps and graphs. If you see a circle keeps changing
its color below, you already have the plugin or you are using
a browser with native SVG capabilities. If not, please download
and install it (click the banner on the right). The use of
Mozilla Firefox 1.5+ and Opera 9+ has been being tested.
Let's start creating a dynamic drought index >>
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