Graphics Programs Reference
In-Depth Information
28.1 Example: Meteorological Database
In this example we create a structure using the
struct
function. We
create a meteorological observation database as follows:
meteo = struct('Site',{'Adelaide','Sydney'},...
'Time',{2.34},...
'Temperature',{24 19},...
'Pressure',{10231015})
This structure consists of temperature and pressure measurements at
two different times at Sydney and Adelaide. The Adelaide data was
taken at 2:30:
>> meteo(1)
ans =
Site: 'Adelaide'
Time: 2.3000
Temperature: 24
Pressure: 1023
and the Sydney data was taken at 4:00:
>> meteo(2)
ans =
Site: 'Sydney'
Time: 4
Temperature: 19
Pressure: 1015
Let us suppose we have some new Sydney data taken at 8:00 and 11:00.
We add this as follows:
>> meteo(2).Time(2:3) = [8 11];
>> meteo(2).Temperature(2:3) = [16.5 15.3]
meteo =
1x2 struct array with fields:
Site
Time
Temperature
Pressure
>> meteo(2).Temperature
ans =
19.0000
16.5000
15.3000
The pressure meter broke so we do not have new pressure data for these
two new times. We could leave the pressure field with one entry, but
it might be better to indicate the absence of data more explicitly with
NaN
s:
