Reversing the color scale in shape map using spmap

[Mai Goetzsche]

Dear Statalists,

I am investigating the effect of a liberalisation of the divorce law on the fertility rates in Danish municipalities (this effect is negative and significant). The data I am using is panel data. To see which municipalities have been affected the most, I have calculated the percentage change in the fertility rate between 2008 and 2018 for each municipality. Now, I want to illustrate this using Stata's command

spmap

.

My problem is that the municipalities that are affected the most have the lowest value and thus the lightest shade whereas the municipalities that are affected the least have the highest value and thus the darkest shade. This seems counterintuitive which is why I want to reverse the color scale in the shape map.

Here is my code:

clear all
cd /Users/maigoetzsche/Desktop
ssc install shp2dta
ssc install spmap

use denmark_dat, clear
rename NAME_2 municipality
replace municipality = "Copenhagen" if  municipality =="København"
replace municipality = "Ærø" if  municipality =="Ærø"
replace municipality = "Aarhus" if  municipality =="Århus"
replace municipality = "Høje-Taastrup" if  municipality =="Høje Taastrup"
replace municipality = "Vesthimmerlands" if  municipality =="Vesthimmerland"
save  denmark_harm, replace

import excel "Datasheets.xlsx", sheet("Data10") firstrow clear
drop id            
save main, replace    
use denmark_harm, clear
merge 1:1 municipality using main
 
spmap divorcechange using denmark_co, plotregion(lcolor(black)) fcolor(OrRd) id(id) osize(vthin vthin vthin vthin) ndsize(vthin)  ///  
legend(position(2)) legtitle("fertilitychange") clnumber(9) legend(size(medium))

This gives the following:

Can anyone help?

Thank you in advance.

Best,
Mai

[Julian Schaper]

Hey,

I have the same question. I just cannot find a way to reverse the shades of blue of my map without digging into more complicated syntax of colorpalette. Can someone give a hint if there is a simple way of solving this?

Best,
Julian

[Warwick Smith]

I'm also trying to solve this one. Any solutions? My current workaround is to multiply my variable by -1 but it's far from ideal for the legend.

[Julian Schaper]

Eventually I managed to solve it this way:

First install the following packages:

ssc install palettes, replace    // for color palettes
ssc install colrspace, replace   // for expanding the color base

Then generate a local in order to reverse the scheme. In my case this was darkest blue for lowest number:

colorpalette Blues, select(2 4 6 8) nograph reverse // this reverses the colors, here I selected 4 different blues
local colors `r(p)'

Then when mapping simply use this local when assinging fcolor:

spmap clashes_tot using coord, id(id) fcolor("`colors'")

Perhaps there are better ways but I hope this helps you.

Best,
Julian

[Francesco Colcerasa]

Eventually I managed to solve it this way:

First install the following packages:

ssc install palettes, replace // for color palettes
ssc install colrspace, replace // for expanding the color base

Then generate a local in order to reverse the scheme. In my case this was darkest blue for lowest number:

colorpalette Blues, select(2 4 6 8) nograph reverse // this reverses the colors, here I selected 4 different blues
local colors `r(p)'

Then when mapping simply use this local when assinging fcolor:

spmap clashes_tot using coord, id(id) fcolor("`colors'")

Perhaps there are better ways but I hope this helps you.

Best,
Julian

Hi, I tried your command and it works!
However, the areas that should display the least intense colour are white-filled. I tried to change the color scale within "select", but with no results. Can you help me?

Best,
Francesco