How to adjust the legend length in rworldmap?

问题

I would like to adjust the legend bar of rworldmap.

    mapCountryData(df, 
                   nameColumnToPlot="users",
                   xlim=NA,
                   ylim=NA,
                   mapRegion="World",
                   numCats=30,
                   catMethod="pretty",
                   addLegend=TRUE,
                   mapTitle="map1",
                   colourPalette=c("heat")) 
    do.call(addMapLegend, c(mapParams, legendLabels="all",
                           legendWidth=0.5,
                           legendIntervals="data",
                           legendMar=2))     

I was able to generate the map, but failed to adjust the legend bar. The legend layout was across the map, which did not look well.

Error in do.call(addMapLegend, c(mapParams, legendLabels = "all", legendWidth = 0.5, : object 'mapParams' not found

I am not able to provide the dataset. Can anyone help review which part of my scripts generates the error and how can I fix it? Thank you.

回答1:

Try adding mapParams <- to the start of your first line.

Also have a look at package tmap which is more up-to-date than rworldmap.

More generally, Stackoverflow recommends that you create a small 'reproducible' example, that would allow people to recreate your issue and test solutions.

Good luck.

mapParams <- mapCountryData(df, 
                   nameColumnToPlot="users",
                   xlim=NA,
                   ylim=NA,
                   mapRegion="World",
                   numCats=30,
                   catMethod="pretty",
                   addLegend=TRUE,
                   mapTitle="map1",
                   colourPalette=c("heat")) 

do.call(addMapLegend, c(mapParams, legendLabels="all",
                       legendWidth=0.5,
                       legendIntervals="data",
                       legendMar=2))

来源：https://stackoverflow.com/questions/49314761/how-to-adjust-the-legend-length-in-rworldmap