MAP CREATION USING ARCVIEW: PRACTICAL ISSUES Tom Largo Bureau of Epidemiology November 13, 2006

TOPICS TO COVER Optimal shades to select for B & W printed MDCH documents Determination of appropriate classification type –Equal Interval –Quantile –Natural Breaks –Standard Deviation

SHADING Max number of discernible groups: 4 –white –black –two shades of grey To determine optimal shading, had to work backwards – viewing copy of PDF

SPECIFICATIONS In ArcView 3, the specifications for the two grey shadings were: HueSaturationValueResult

SPECIFICATIONS In ArcView 9, the specifications are: ValueResult 82% 58%

EXAMPLE

Problem!

EXAMPLE One solution

ONE LAST SUGGESTION See proof of final from printer to ensure can distinguish grey shades

SELECTING A CLASSIFICATION TYPE Each type will usually result in a different illustration Impact on viewer will be different depending on type selected Q: How do you determine which one to use?

EQUAL INTERVAL (equal rate range)

QUANTILE (equal number of counties in each category)

NATURAL BREAKS (id natural breakpoints in data distribution)

STANDARD DEVIATION (ranges based on std dev around mean rate)