datapreprocessor
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Class: Image_Graph_DataPreprocessor_Array

Source Location: /Graph/DataPreprocessor/Array.php

Class Overview

Image_Graph_DataPreprocessor
   |
   --Image_Graph_DataPreprocessor_Array

Format data as looked up in an array.


Methods


Child classes:

Image_Graph_DataPreprocessor_Sequential
Formatting values using a sequential data label array, ie. returning the "next label" when asked for any label.

Inherited Variables

Inherited Methods


Class Details

[line 56]
Format data as looked up in an array.

ArrayData is useful when a numercal value is to be translated to something thats cannot directly be calculated from this value, this could for example be a dataset meant to plot population of various countries. Since x-values are numerical and they should really be country names, but there is no linear correlation between the number and the name, we use an array to "map" the numbers to the name, i.e. $array[0] = 'Denmark'; $array[1] = 'Sweden'; ..., where the indexes are the numerical values from the dataset. This is NOT usefull when the x-values are a large domain, i.e. to map unix timestamps to date-strings for an x-axis. This is because the x-axis will selecte arbitrary values for labels, which would in principle require the ArrayData to hold values for every unix timestamp. However ArrayData can still be used to solve such a situation, since one can use another value for X-data in the dataset and then map this (smaller domain) value to a date. That is we for example instead of using the unix-timestamp we use value 0 to represent the 1st date, 1 to represent the next date, etc.




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Class Methods


constructor Image_Graph_DataPreprocessor_Array [line 70]

Image_Graph_DataPreprocessor_Array &Image_Graph_DataPreprocessor_Array( array $array)

Image_Graph_ArrayData [Constructor].



Parameters:

array   $array   The array to use as a lookup table

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Documentation generated on Wed, 15 Sep 2004 10:30:14 +0200 by phpDocumentor 1.2.3