2.2.6. imageData

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Purpose

Generate PNG image from data in given column with fastest varying index along the width. Alternatively, use overall ASCIItable as 2D data set. The intrinsic coordinate frame used by imageData is scanline-derived with the origin in the top-left corner, x pointing to the right, and y pointing downward.

Operates on given file(s) or STDIN STDOUT.

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Usage

> imageData options [file(s)]

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Options

--label / -l string [ all ]

column containing data

--range / -r float float [ auto ]

range of data values (min max)

--dimension / -d int int [ native ]

dimension of data field (width height)

--abs [ False ]

use absolute data values

--log [ False ]

use natural logarithm of data values

--fliplr [ False ]

flip image around vertical axis

--flipud [ False ]

flip image around horizontal axis

--log [ False ]

use natural logarithm of data values

--color string [ gray ]

color scheme to use for values

--invert [ False ]

invert color scheme

--show [ False ]

show resulting image

--crop int int int int [ 0 0 0 0 ]

pixels cropped on left, right, top, bottom of image

--pixelsize / -N int [ 1 ]

pixels per data point in image along x and y

--pixelsizex / -x int [ 1 ]

pixels per data point in image along x

--pixelsizey / -y int [ 1 ]

pixels per data point in image along y

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Example

Single data column

Suppose we have an ASCIItable that contains a column of two-dimensional data as in » type « below. The additional columns » x « and » y « are not required and not considered either, but correspond to the interpretation of the data sequence based on --dimension 3 2, i.e. 3 points along x for each of two rows along y.

1 head
x y type
1 1 1
2 1 1
3 1 2
1 2 1
2 2 3
3 2 0

With

> imageData --label type --pixelsize 10 --dimension 3 2

the output shown in Figure 1 results.

Two-dimensional data array

For an ASCIItable that directly contains a two-dimensional representation of a data field, such as

0 head
-1    0 0 0 0 0 0 0
-0.33 0 0 2 0 2 0 0
0.33  0 0 0 0 0 0 0
1     0 0 0 2 0 0 0
1.67  0 1 0 0 0 1 0
2.33  0 0 2 2 2 0 0
3     0 0 0 0 0 0 0

the processing with

> imageData --pixelsizex 10 --pixelsizey 15 --color bluered --invert --range -1 3

yields the output shown in Figure 2.