dhis2-users team mailing list archive

[Jan Henrik Øverland <janhenrik.overland@xxxxxxxxx>]

Equal counts is not implemented in the server/png version.


On Thu, Feb 20, 2014 at 6:14 PM, Bob Jolliffe <bobjolliffe@xxxxxxxxx> wrote:

> Hi Bram
>
> Interesting point about the red-yellow-green combo.  These are the traffic
> light colours which are apparently sufficiently ubiquitous that you can say
> red=bad and green=good without even explaining further.  If snooker was as
> well known as traffic lights we could do a whole range from red through to
> pink :-)
>
> But in general, using hues as per Knut's colour brewer link is going to be
> the best bet for most cases of numeric data.  You can even print to black
> and white printers and maintain the message.
>
> Good point about "equal counts".  I actually did do that but somehow it
> rendered different on the dashboard.
>
> Bob
>
> On 20 February 2014 15:54, Bram Piot <bram.piot@xxxxxxxxx> wrote:
>
>> Hi Bob,
>>
>> I don't think there's one single rule that will fit all when it comes to
>> choosing your symbols or colours for a thematic map depicting numeric
>> values. There's nothing wrong with say a red/yellow/green colour scheme if
>> you are showing for example reporting rates, where low (red) = bad and high
>> (green) = good. If I were to map out HIV prevalence, then I may go from
>> green (low values) to red (high prevalence). More "neutral" variables such
>> as population density are usually better off with a graduated scheme from
>> light to dark, e.g. pale to dark brown.
>>
>> Maybe the only basic rules are that there should be some logic in the
>> choice of colour ramps, and to keep it simple (don't overload your map,
>> don't use 15 different classes each with a different colour when you only
>> have 20 districts!). I must agree that the current colour scheme for ANC1
>> and ANC2 coverage by chiefdom in the demo site can definitely be improved:
>> too many colours that are not in a logical order. Your diarrhea map looks
>> better, though it would be even better if you changed the classification
>> type to "equal counts" rather than "equal intervals".
>>
>> Agree with what has been requested recently by Knut: option to display
>> polygon data (e.g district) by symbol, not just colour, and include more
>> symbols because currently it's rather limited. Especially for categorical
>> values the legend behaviour could be greatly improved. Bar/Pie charts as
>> symbols on the map would be cool but not a priority as there are more
>> suitable tools for that.
>>
>> bram
>>
>>
>> On 20 February 2014 17:27, Bob Jolliffe <bobjolliffe@xxxxxxxxx> wrote:
>>
>>> Hi
>>>
>>> I am no expert here, but I was talking last week with someone who had
>>> just been on a GIS course.  She made the interesting observation that when
>>> you are displaying numerical data as shaded regions on a map, you should
>>> not mix primary colours in the same gradated scale because what you end up
>>> with is sort of rubic cube kaleidoscope of colour rather than a clear
>>> gradation of values.
>>>
>>> If that is good advice then I think our demo site could be improved as
>>> presently it seems like a good example of bad practice, where we have mixed
>>> red, green and blue with joyful and cheerful abandon :-)
>>>
>>> I had a go to change the Diarrhoea map on the dashboard at
>>> http://apps.dhis2.org/dev/dhis-web-dashboard-integration/index.action and
>>> I think it is true that it conveys the data better than the extreme
>>> multi-coloured ones around it.  Even if the distribution of data between
>>> bands is not so interesting.  Anyone agree or disagree? (the data will only
>>> be there for a short while longer)
>>>
>>> If there is a best practice to be had here regarding colour selection I
>>> guess we should promote it, particularly with default offerings so that
>>> people have to be quite deliberate in order to go astray.
>>>
>>> Bob
>>>
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>>>
>>
>
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