Point Map Chart

Vvidget Code > Dictionary > Point Map Chart

This section explains how to form a dictionary for a Point Map Chart such as these:

Rectilinear Point Map	X-Log Point Map

A point map is a sequence of values that are arranged on a regular 2D grid, mapped to different colors and then those colors used as a fill color for rectangles. When the grid is dense then the point map chart can appear to be an image. Selecting the appropriate color mapping is somewhat of an art form, but blue for cold (or low) and red for hot (or high) is an obvious choice. However, there are other color mappings that produce amazing representations and there are inappropriate color mappings that create mass confusion so that one need be careful when doing the mapping. The grid can reside on a nonlinear coordinate system and be represented by turning on the stroke value for the rectangular cells. Much of that is very domain specific and beyond the scope of this reference manual.

An example code fragment illustration follows:


/* Start of Illustration Code Fragment */



[constructor VC_append_key:"chart_type" string_value:@"point map"];

[constructor VC_append_key:"chart_subtype" string_value:@"default"];

[constructor VC_append_key:"chart_format_type" string_value:@"default"];

[constructor VC_append_key:"title" string_value:@"My Title"];

[constructor VC_append_key:"x_title" string_value:@"My X Title"];

[constructor VC_append_key:"y_title" string_value:@"My Y Title"];

[constructor VC_append_key:"grid_x_length" string_value:@"5"];

[constructor VC_append_key:"grid_x_minimum" string_value:@"1.0"];

[constructor VC_append_key:"grid_x_maximum" string_value:@"5.0"];

[constructor VC_append_key:"grid_y_length" string_value:@"5"];

[constructor VC_append_key:"grid_y_minimum" string_value:@"1.0"];

[constructor VC_append_key:"grid_y_maximum" string_value:@"3.0"];

[constructor VC_append_key:"color_map_1_type" string_value:@"1"];

[constructor VC_append_key:"color_map_2_type" string_value:@"1"];

[constructor VC_append_key:"color_map_1_length" string_value:@"32"];

[constructor VC_append_key:"color_map_2_length" string_value:@"32"];

[constructor VC_append_key:"color_map_rgb_11" string_value:@"FF0000FF"];

[constructor VC_append_key:"color_map_rgb_12" string_value:@"FFFFFFFF"];

[constructor VC_append_key:"color_map_rgb_21" string_value:@"FFFFFFFF"];

[constructor VC_append_key:"color_map_rgb_22" string_value:@"0000FFFF"];

[constructor VC_append_key:"data_values" string_value:@"1.0 2.0 3.0 4.0 5.0 1.1 2.1 3.1 4.1 5.1 1.2 2.2 3.2 4.2 5.2 1.3 2.3 3.3 4.3 5.3 1.4 2.4 3.4 4.4 5.4"];



/* End of Illustration Code Fragment */

The code fragment above can be inserted into the illustration code section of the Illustration project for an immediate running Cocoa application. For additional information consult the Illustration section.

The following table defines the dictionary key and value pairs:

Chart Specific Entries
Key	Value Description
chart_type¹	The string point map, indicating a Point Map Chart.
chart_subtype¹	One of the strings {linear , semilog, x-log y-linear, log-log, polar, r-log} which specifies the graph coordinate type of {X-Linear, Y-Linear}, {X-Linear, Y-Log}, {X-Log, Y-Linear}, {X-Log, Y-Log}, {R-Linear, Theta-Degrees}, {R-Log, Theta-Degrees} respectively.
chart_format_type¹	Always 0 (aliased to default).
title	The main title of the graph. If this key is not present then the template's title is used.
x_title	The x title of the graph. If this key is not present then the template's x-title is used.
y_title	The y title of the graph. If this key is not present then the template's y-title is used.
grid_x_length	The number of grid cells in the x-direction.
grid_x_minimum	The minimum x-value of the grid.
grid_x_maximum	The maximum x-value of the grid.
grid_y_length	The number of grid cells in the y-direction.
grid_y_minimum	The minimum y-value of the grid.
grid_y_maximum	The maximum y-value of the grid.
color_map_1_type	The color mapping type (0, 1, 2, 3).
color_map_1_length	Number of colors in map 1.
color_map_rgb_11	Beginning color of the color mapping.
color_map_rgb_12	Ending color of the color mapping.
color_map_2_type	The color mapping type (0, 1, 2, 3).
color_map_2_length	Number of colors in map 2.
color_map_rgb_21	Beginning color of the color mapping.
color_map_rgb_22	Ending color of the color mapping.
templates	A custom Templates directory.
data_values	A white space delimited list of values representing the z-values of the grid matrix. See Data Oriented keys for additional information and keys.

¹ Do not include this key value pair in the Interface Builder Plugin Inspector input string. It is included for you automatically.

If you incorporate this functionality into your own application then please consult Cocoa Programming. If you incorporate this functionality into CLI scripts then please consult Script Programming.

You can also modify the following Templates:

Template Document Names
Template	Description
PVST_Point_Map_Chart	Forms the static attributes for the X-Linear, Y-Linear graph.
PVST_X_Log_Point_Map_Chart	Forms the static attributes for the X-Log, Y-Linear graph.
PVST_Y_Log_Point_Map_Chart	Forms the static attributes for the X-Linear, Y-Log graph.
PVST_XY_Log_Point_Map_Chart	Forms the static attributes for the X-Log, Y-Log graph.
PVST_Polar_Point_Map_Chart	Forms the static attributes for the polar graph.
PVST_R_Log_Point_Map_Chart	Forms the static attributes for the r-log graph.

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