I want to plot latitude and longtitude.

I have the data as shown below:

9.00000 -44.86 167.10 3.99

9.00833 -44.84 167.13 4.01

9.01667 -44.83 167.16 4.03

9.02500 -44.81 167.19 4.05

9.03333 -44.80 167.22 4.08

9.04167 -44.79 167.25 4.10

9.05000 -44.77 167.28 4.12

9.05833 -44.76 167.31 4.14

9.06667 -44.75 167.34 4.16

9.07500 -44.73 167.37 4.19

9.08333 -44.72 167.39 4.2

9.09167 -44.71 167.42 4.22

9.10000 -44.69 167.45 4.23

9.10833 -44.68 167.48 4.22

9.11667 -44.67 167.50 4.23

9.12500 -44.65 167.53 4.24

9.13333 -44.64 167.56 4.26

9.14167 -44.63 167.58 4.27

9.15000 -44.61 167.61 4.29

9.15833 -44.60 167.64 4.31

There are 4 columns and 20 rows. The first, second, third and fourth columns show Time, Latitude, Longtitude and the amount of plasma, respectively. I try to write an m file to plot latitude and longtitude using the code below:

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

data = xlsread('hoki.xls'); %Import data

figure('Color','white')

latlim = [-50 -30];

lonlim = [160 180];

ax = usamap(latlim,lonlim);

axis off

hold on

geoshow('landareas.shp', 'FaceColor', [0.9 0.9 0.9])

for k = 1:20 %row 1 - 20

    hok0 = [data(k,2) data(k,3)];

    l = data(k,4);

    if l >= 2 & l < 4
            figure(k), plotm(hok0(1), hok0(2),'sr','MarkerFaceColor','r')
            imwrite(0,map,'k.hdf','Compression','none',...
                'WriteMode','append')
        clf
    elseif l >= 4 & l < 6
            figure(k), plotm(hok0(1), hok0(2),'sb','MarkerFaceColor','b')
            imwrite(0,map,'k.hdf','Compression','none',...
                'WriteMode','append')
        clf
    else l >= 6 & l < 8
            figure(k), plotm(hok0(1), hok0(2),'sy','MarkerFaceColor','y')
            imwrite(0, map,'k.hdf','Compression','none',...
                'WriteMode','append')
        clf
    end      
end

My aim is to plot latitude and longtitude on New Zealand mab. The point coulours of lat and lon will be classified as the amount of plasma including red, blue and yellow. I try to control the program as the process below:

1) choose k =1: hok0 = [data(k,2) data(k,3)];

2) plot figure(1) using: figure(k), plotm(hok0(1), hok0(2),'sr','MarkerFaceColor','r')

3) export immage 1 using: imwrite(0,map,'k.hdf','Compression','none',... 'WriteMode','append')

4) close figure(1) using: clf

5) continue to plot figure(2) to figure(20)

There is an error while the program try to plot figure(2). help me please.

[Walter Roberson]

The first argument ti imwrite() must be the array of data to write. You are writing a scalar 0 each time.