Add vertical reference lines in horizontal bars

[Cindy Zheng]

I am using -graph hbar- to create horizontal bars on means by groups. Does anyone know how to add vertical reference lines in the chart?

In the example chart generated by the following code, there would be four reference lines, one on the first 2 bars (N Eng and Mid Atl) for NE, one for N Central (ENC and WNC), one for South (S Atl, ESC, and WSC), and one for West. The values of the reference lines are 28 for NE, 22 for N Central, 46 for South, and 46 for West. These are means by region. Thanks in advance!

use https://www.stata-press.com/data/r17/citytemp, clear

graph hbar (mean) tempjan, over(division) over(region) nofill ytitle("Degrees Fahrenheit") ///
title("Average January temperature") ///
subtitle("by region and division of the United States") ///
note("Source: U.S. Census Bureau, U.S. Dept. of Commerce")

[Andrew Musau]

The -yline()- option does this. You have to specify the y axis value or values, e.g.,

yline(29 32 40)

[Cindy Zheng]

Thank you Andrew! The lines show up across groups. Is there anyway each group could have its own reference line as shown the the attached example? Thanks!

[Andrew Musau]

You can do it by creating the graph using twoway and using -dropline()-. In graph hbar, you can use code from the graph editor. You need to repeat the following sequence of commands for each line and change the values highlighted in red below to specify the start and end points of the line. It will take some tinkering.

use https://www.stata-press.com/data/r17/citytemp, clear

graph hbar (mean) tempjan, over(division) over(region) nofill ytitle("Degrees Fahrenheit") ///
title("Average January temperature") ///
subtitle("by region and division of the United States") ///
note("Source: U.S. Census Bureau, U.S. Dept. of Commerce")

gr_edit .plotregion1.AddLine added_lines editor 24 103 24 82
gr_edit .plotregion1.added_lines_new = 1
gr_edit .plotregion1.added_lines_rec = 1
gr_edit .plotregion1.added_lines[1].style.editstyle  linestyle( width( sztype(relative) val(.45) allow_pct(1)) color(red) pattern(solid) align(inside)) headstyle( symbol(circle) linestyle( width( sztype(relative) val(.2) allow_pct(1)) color(black) pattern(solid) align(inside)) fillcolor(black) size( sztype(relative) val(1.52778) allow_pct(1)) angle(stdarrow) symangle(zero) backsymbol(none) backline( width( sztype(relative) val(.2) allow_pct(1)) color(black) pattern(solid) align(inside)) backcolor(black) backsize( sztype(relative) val(0) allow_pct(1)) backangle(stdarrow) backsymangle(zero)) headpos(neither) editcopy

[Cindy Zheng]

Thanks Andrew! I will look into creating the graph using twoway and using -dropline()-.

[Tiago Pereira]

Thank you, Andrea. Also very helpful for our current projects!