Line plots

What is a good line plot?

• Clear• Clean• Hightlight the key lines: thick

Example: Global mean surface temperature

Don’t be mislead by the aspect ratio

Line plots — Plot • Syntax: plot, x, y plot, y (the data points are plotted against

corresponding array indices) plot, x, y, max=dmax, min=dmin (limit the

maximum and minimum data values to be plotted)

• Overplotting oplot, x, y• Scatter plots plot, x, y, psym=symbol_code

Line plot customization• Keywords

General: title, charsize, charthick

For data lines: linestyle, thick, psym, symsize, color,

/nodata, /noerase, /noclip

For axis: /ynozero, /xlog, /ylog,

[xyz]title, range, style, thick

[xyz]ticks, tickv, tickname, ticklen

Examplex=findgen(10)y=x^2.0

plot, x, y, charsize=2.0, $ title=‘Google stock’, xtitle=‘Time (month)’,

ytitle=‘Dollar’, $ thick=4, $ xrange=[0, 9], xstyle=1, yrange=[0, 85], ystyle=1, $ xticklen=0.01,yticklen=0.01, $ xticks=9, yticks=4, $ ytickv=[0,10,20,40,60],

ytickname=[‘0’,’10’,’20’,’40’,’60’]

Plot: Omitting default axes

• Plot, x, y, xstyle=4 (or 8), ystyle=4 (or 8)

Line plots: Logarithm and bar plots

• Logarithm: Plot, x, y, /xlog, /ylog

• Bar plot: bar_plot, data, barnames=bn

Find the longitude/latitude index for a specified position

Lon=findgen(144)*2.5Lon1= 277.0 ; Columbus Ohiox=abs(lon1-lon)Index=where(x eq min(x))i=index(0)Print, i, lon(i), lon1

Lat=findgen(73)*2.5-90.0Lat1= 40.0 ; Columbus OhioX=abs(lat1-lat)Index=where(x eq min(x))j=index(0)Print, j, lat(j), lat1

Assignment VIMake your plots for Assignment III as good as possible (thick lines, big charsize, correct xrange/yrange, short tick length, emphasize with symbols, omit some axes, …)

1. Read and plot the population history of Columbus, OH http://www.biggestuscities.com/city/columbus-ohio and the population history of 5 other cities of your interest. Please omit the top, bottom and right axes.

2. Please go to http://www.esrl.noaa.gov/psd/data/climateindices/list/ Read and plot any four of the climate indices (e.g. the last four: Global Mean Lan/Ocean Temperature, Solar Flux, Northeast Brazil Rainfall Anomaly, SW Monsoon Region rainfall). Please emphasize the data points using some symbols.

Assignment VI (cont.)

3. Please go to University of Wyoming sounding data site: http://weather.uwyo.edu/upperair/sounding.html Click on one station of your interest. Read and plot the profile of temperature (temp) versus pressure for the sounding. The range for pressure should be [1000, 100]. Please make two plots with one using ordinary pressure coordinate, and the other using logarithm for the pressure coordinate.

4. Go to: http://lightning.sbs.ohio-state.edu/geog8901/data/ Read the netCDF file ncep_skt.mon.ltm.nc for global surface skin temperature (skt) climatology (mean values for each of the 12 months). Find the longitude/latitude index for 6 different cities (one each for North America, South America, Asia, Europe, Africa and Antarctica). Make a 6 panel plot of the skt change throughout the year for each city.