University of Maryland, College Park
Spring 2006
Viz4All Hyunyoung Song (hsong@cs) Maryam Farboodi (farboodi@cs) Hamid Haidarian Shahri(hamid@cs)
Introduction

When deciding to use color in web design, the first question which comes to mind is: Does Color Really Matter?
Here is an answer: "Research reveals all human beings make a subconscious judgment about an . .. item within 90 seconds of initial viewing and that between 62% and 90% of that assessment is based on color alone."
The above statement from the Institute for Color Research, though a bit overstimated, demonstrates the dominant role that color plays in influencing potential users. Althought in a lot of design cases color is used as a compliment,we know that for better or for worse, color has an overwhelming impact on website viewers.

With the above introduction, we proceed to the main focus of this page, namely the color combination which used for an application. Here, we will introduce ColorBrewer, a web tool for selecting color schemes for thematic maps, most usually for choropleth maps.

ColorBrewer is implemented in Flash. It includes 35 basic schemes with different numbers of classes for over 250 possible versions. Each scheme has CMYK, RGB, Hex, Lab, and AV3 (HSV) specs for the colors. The software is designed simply to list color specs for a scheme you find useful so you are able to create these colors in the mapping software you are using. It is designed specifically for you to look up color sets to use in other mapping environments user is working in. Although this application is specifically designed for mapping, but we believe the recommended color applets can be used in and application.

ColorBrewer contains nice features which let user choose colors most suitable for his own application. Fisrt user must choose the number of map classes he would like to examine. Choosing the number of data classes is an important part of map design. Increasing the number of data classeswill result in a more"information rich" map by decreasing the amount of data generalization. However, too many data classes may overwhelm the map reader with information and distract him from seeing general trendsin the distribution. In addistion, a large number of classes may compromise map legibility: more classes require more colors that become increasingly difficult to tell apart.
Many cartographers advise the user to use five to seven classes.

The next step is to choose the type of schema user wants to examine.

Schemas
There are three main types of schemas:

When user chose his desires schema, a set of mini legends will appear showing the general appearance of the color schemes prepared for the scheme type user chose. Clicking on one of these choices fills the map at right with the corresponding colors.

Special Feature
One intersting feature of the system is a box in the buttom left of the screen. When user chooses any color pallet, the corresponding big legent appears in the lower left. By clicking any of the color spec types above the big legend, the relative color specs will appera to the right of the legend box. Moreover, The icons to the left of the legend in the lower left of the screen suggest contexts in which the particular scheme should work.More specifically:
The "?" and "X" marks indicate how well the pallet works in each regard.

Web Accessibility