Custom Sequential Classes for a Map

[Anonymous]

Folks,

I have a map showing values by UK Postcode (area or district depending on selections).  A few of my values are very big, and then fall away sharply, so I don't really want to use the standard sequential classes as the middle isn't really used.

I have created an expression for colouring like so (choice of two metrics - lives or sum assured), but I have hard coded the boundaries:

if(if([Metric]='Lives',sum([LIVES]),sum([TSA]))<10000000,rgb(255,255,204), 

if(if([Metric]='Lives',sum([LIVES]),sum([TSA]))<50000000,rgb(255,237,160),  

     if(if([Metric]='Lives',sum([LIVES]),sum([TSA]))<100000000,rgb(254,217,118),

         if(if([Metric]='Lives',sum([LIVES]),sum([TSA]))<500000000,rgb(254,178,76),

             if(if([Metric]='Lives',sum([LIVES]),sum([TSA]))<1000000000,rgb(253,141,60),

     if(if([Metric]='Lives',sum([LIVES]),sum([TSA]))<5000000000,rgb(252,78,42),

      if(if([Metric]='Lives',sum([LIVES]),sum([TSA]))<10000000000,rgb(227,26,28),

       if(if([Metric]='Lives',sum([LIVES]),sum([TSA]))<25000000000,rgb(189,0,38),rgb(128,0,38)

                           ))))))))

What I really want to do is set the boundaries as a % of the highest amount in a postcode.  Everytime I try something it calculates the maximum for THAT particular postcode and therefor sets the colour based on 100% of the maximum.

Any ideas?

Many thanks in advance for the help.

Cheers

Chris

[Gysbert_Wassenaar · Accepted solution]

Ok, then replace the hardcoded values with a % multiplied by the max:

     0.2 * $(=max(aggr(sum( ...), Dim1, Dim2, ..., DimN)))

Replace Dim1, Dim2, ..., DimN with whatever dimensions the sum should be aggregated over.

[Anonymous]

Many thanks - that works a treat....

Cheers

Chris