Hello ColorBrewer user. I have been
getting good feedback
from
users from all over, and I am glad this web tool is helping you make
better
maps.
I have offprints from a journal article with a full set of
printed
schemes with CMYK specs that I can mail out to you (item 1. below). You
can download an Excel file of RGB specs for the full set of
schemes
(2.). I also added notes below on citation (5.) and a related
book
and
course (6.).
1.
CMYK specs
A full set of CMYK color charts for ColorBrewer schemes are printed in CaGIS andI
have
offprints that I will send out to you (free). I admit to
being slow responding to these requests so pester me if I don't
get back to you. Here is the article reference:
Brewer, Cynthia A., Geoffrey W. Hatchard and Mark
A.
Harrower, 2003, ColorBrewer in Print: A Catalog of Color Schemes for
Maps, Cartography and Geographic Information Science
30(1):
5-32.
The color charts are reprinted as an Appendix in my
book Designing Better Maps: A Guide
for GIS
Users. This
version of the charts has both CMYK and RGB specs next to each color
patch.
These color charts will assist ColorBrewer users whose color maps are
professionally printed using an offset lithographic press. Geoff
Hatchard
and I imageset negatives, proofed, and adjusted the ColorBrewer
schemes to prepare this article in the summer of 2002. We improved the
CMYK specs for about 80 colors and adjusted all of the corresponding
numbers (RGB, Lab, Hex, and AV3). The costs of the negatives, proofs,
and Geoff's time were funded by our NSF
Digital
Government
grant through GeoVISTA.
Two other articles are also out (but no color charts are in
these
ones):
Brewer, Cynthia A., 2003, A Transition in
Improving Maps:
The ColorBrewer Example, in U.S. Report to the International
Cartographic Association, special issue of Cartography and
Geographic Information
Science 30(2):155-158.
Mark A. Harrower and Cynthia A. Brewer, 2003,
ColorBrewer.org: An Online Tool for Selecting Color Schemes for Maps, The
Cartographic Journal 40(1): 27-37.
2. RGB file
I have had some requests for these color schemes in alternative
formats from people who want to build the schemes into their own
programs or capture them more efficiently. I have linked Excel
files with all of the ColorBrewer RGB
numbers for each color in each scheme at each number of
classes (1690
lines).
There are two RGB files on this page.
One is bare-bones with schemes in alphabetical order. In the second
file the schemes are in the same order as they appear in
ColorBrewer and RGB color patches are embedded as comments in each row.
Thank you to David P. Ryan for initiating this upgrade to the file and doing the Excel programming to insert the color patches.
In return for using these specs, I would
like
you to lavishly credit
the source of the color schemes (see item 5.
below).
Also, please take a moment to email me a short note on how you
will use the color sets <cbrewer@psu.edu>.
That helps me make the case of applicability of my work
for University merit evaluations. I also enjoy news about how
this
design work is useful in varied applications.
3. Colorblind In addition to my
rough guidance on
suitability of schemes for colorblind readers, you can do a better job
of preparing
map colors for colorblind map readers using the tools at www.vischeck.com.
Capture and
submit
your map legend as a small graphics file and see what changes their
'Daltonize' function suggests. I learned about this tool in a
newsletter article by
Jeff Nugent (p.
6).
If you know
of other colorblind utilities on the web for diagnosing or
adjusting graphics, please email me with a tip. This is a topic I have
previously
done research on and I am interested in progress on new tools. The
research
behind Vischeck is sound so I suspect this tool is giving pretty good
results,
though the details of the translation to RGB on your particular
computer
screen will potentially diminish the results. Thanks.
Steve Gardner's
Master's thesis
evaluated the ColorBrewer schemes for colorblind readers. I've linked
his whole thesis with his
permission (6.1MB .PDF file or 5.5MB
zipped which isn't smaller but it may download more
smoothly). He has recommendations that I have
not yet incorporated into the schemes, so I want to get that info out
to you. Please cite his work
if you find it useful. Also, I hope his work prompts further student
research. Steve
is now working at the National Geographic Society.
4. Copyright I
have adopted an 'Apache license' for ColorBrewer and its color schemes, on the initial advice of Frank
Hardisty. Alan Isaac recommended updating to Version 2.0 for compatiblity with GPL licenses. Thanks Frank and Alan.
Here is the license:
Apache-Style Software License for ColorBrewer
software and ColorBrewer Color Schemes
Copyright (c) 2002 Cynthia Brewer, Mark Harrower,
and The Pennsylvania State University.
Licensed
under the Apache License, Version 2.0 (the "License"); you may not use
this file except in compliance with the License. You
may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0 Unless
required by applicable law or agreed to in writing, software
distributed under
the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS
OF ANY KIND, either express or implied. See the License for the specific
language governing permissions and limitations under the License.
This text from my earlier Apache
License Version 1.1 also remains in place for guidance on attribution
and permissions:
Redistribution
and use in
source and binary forms, with or without modification, are permitted
provided that the following conditions are met:
1.
Redistributions as
source code must retain the above copyright notice, this list of
conditions and the following disclaimer.
2.
The end-user
documentation included with the redistribution, if any, must include
the following acknowledgment:
"This
product includes
color specifications and designs developed by Cynthia Brewer
(http://colorbrewer.org/)."
Alternately,
this
acknowledgment may appear in the software itself, if and wherever such
third-party acknowledgments normally appear.
4.
The name "ColorBrewer"
must not be used to endorse or promote products derived from this
software without prior written permission. For written permission,
please contact Cynthia Brewer at cbrewer@psu.edu.
5.
Products derived from
this software may not be called "ColorBrewer", nor may "ColorBrewer"
appear
in their name, without prior written permission of Cynthia Brewer.
5. Citation
Ahhh, that lavish
citation I'm hoping for...
Wording depends on context and I'm not too picky. If you add a note
in the corner of a map, how about one of these:
- Colors from www.ColorBrewer.org by
Cynthia A.
Brewer, Geography, Pennsylvania State University.
- Map colors based on
www.ColorBrewer.org, by
Cynthia A. Brewer, Penn State.
- Color symbols: ColorBrewer.org
A reference in a journal article or report might look like:
- Brewer, Cynthia A., 200x.
http://www.ColorBrewer.org, accessed date.
6. Learning Map
Design
And if you are looking for more advice on mapping, take a look at my
map
design handbook: Designing Better Maps: A
Guide for GIS Users, 2005,
ESRI Press, ISBN
1589480899. Here's
the Amazon link and another link to summary chapter
titles and section headings.
I'd like to acknowledge my editors, Judy
Hawkins and Edie Punt, at the press and great book layout
work by Jen Galloway.
My Cartographic Design course has also been re-launched, updated
for ArcGIS 9.0, on the ESRI Virtual Campus. Thank you to Suzanne Boden for
the update work. http://campus.esri.com/
7. Color Ramps
in ArcMap
A variety of people have talked to me about the tedium of typing in
numbers and wanting schemes with more classes. I do think
you'll
need to set the color numbers for each legend patch to get the
best schemes, but here a few tips for ArcMap users.
For ramping from the Symbology tab, type in specs for the end points
and one or two intervening colors from a set of seven or so colors from
a ColorBrewer scheme. Select the middle color(s) you specified and hold
the control key while you ramp. That will approximate the ColorBrewer
scheme without having to type them all in. ColorBrewer colors are each
individually designed (I didn't make them by ramping) so the result
will only be approximate. Using many more colors in a ramp
than I
offer will give you an overall form for the distribution you are
mapping but not differentiable or identifiable color classes.
Also, if you have typed in a set of colors that you use often, get to
know the Style Manager function (Tools
menu->Styles->Style
Manager). You can save each color in a .style file and then
have
those available on the left side of your Symbol Selector window for
your other projects (check your style file name in the list
opened
with the More Symbols button). You can also share these .style files in
your work group. I haven't prepared all these .style files,
but I'd be happy to post them on my web site, or list links
here,
if some of you have already prepared them and would like to share.
These tips are for ArcMap 8.x up to 9.1.
8. More Brewers?
I've had some
conversations with colleagues
about expanding the idea of ColorBrewer to assist mapmakers with other
design challenges. Though extending this somewhat silly naming to other
areas makes me squirm, other researchers seem keen. I'm happy
to
contribute my name to a proliferation of good design advice. Ben
Sheesley is contemplating creating a Type Brewer
for his PhD work, advised by Mark
Harrower, and Olaf Schnabel
is working on a Symbol Brewer for his PhD.
In the cartographic context, I think a “brewer” has
eight characteristics:
1. A selection of choices are offered for a specific
representation challenge (a brewer is not simply a general lesson in
principles).
2. Choices are organized by a set of mapping principles made
explicit to the user (the choices are not merely listed in an
unstructured catalog).
3. All of the choices offered are potentially suitable for
problems for which the tool is used (there are no extreme choices or
straw men in a symbol set).
4. All choices can be examined as categories are explored,
encouraging the user to learn about criteria for applying the existing
variety of choices.
5. Choices are not software specific (solutions can be implemented in
multiple mapping applications).
6. Only basic skills in the use of mapping software are needed to
implement the representations offered (programming skills are not
required).
7. Representations are further augmented with tips on their
suitability, though the user making a quick selection can ignore these
details.
8. Users are encouraged to be critical of the choices
offered,
evaluating them with a display that will reveal potential shortcomings.
These eight points are from the short paper I contributed to
the 2003 U.S. National Report to the International
Cartographic Association. The paper is titled "A Transition in
Improving Maps:
The ColorBrewer Example" [Cartography and
Geographic Information
Science 30(2):155-158].
The photo below shows Olaf (left), Mark (right) and I clowning around
at
the ICC2005 meeting in Spain. You can't you tell what we are
doing?...that's S, C, and T for Symbol-, Color-, and Type-Brewer. Notes
My collaborator and master Flash programmer, Mark
Harrower,
is an Assistant Professor of Geography at the University of
Wisconsin--Madison. Steven
Gardner, Jess
Dobrowolski, and Anthony
Scardino have helped me improve the icon settings for colorblind and
media
suitability (lower left).
The final URL for ColorBrewer is a fairly
long link to my
personal web space at Penn State. You can direct colleagues to the
shorter URL
http://colorbrewer.org
(since it's easier to remember) and it will forward them to
the
actual location of
the program. I'd like to thank Dennis McClendon
for
taking
the lead on creating that nicely-shortened forwarding URL.
A summary collection of all of the ' learn more '
information
from seven buttons, plus icon descriptions, in the ColorBrewer
interface is linked. Basic
instructions on using ColorBrewer
are also available online.
