Modify Dot Density Map

Instructions for use

The user can modify the Parameter Settings of Dot Density Map in the "Dot Density Map" window to achieve a thematic map effect more in line with the requirements.

Operation steps

  1. Select a Dot Density Map layer in Layer Manager, and click the pop-up group dialog box button at the lower right corner of the "Dot Density" group. The setting information of the selected Dot Density Map is displayed in the pop-up "Dot Density Map" window.
  2. Thematic Map Layer: Displays the name of the currently rendered thematic map.
  3. Expression: Displays and sets the Thematic variable used to make the current Dot Density Map, that is, the mathematical expression of a single Property Field or field.
    • Click the Drop-down Button of the "Expression:" combo box, and all Property Fields used to make the Region Dataset of the current Dot Density Map are listed in the pop-up drop-down list;
    • In the drop-down list, select the Thematic variable (single Property Field) of the current Dot Density Map layer; The user can also click the "Expression.." "Item in the drop-down list, and construct the field expression in the pop-up" SQL Expression "" dialog box as the Thematic variable of the Dot Density Map.
    • The current Dot Density Map will re-map in real time according to the modified Thematic variable and refresh Display Effects.

    Note For data Create Thematic Map of Oracle Plus and SQL Plus engine types, field expression can only be field value or field expression, such as (SmID) or (SmID + 1). The By Conditions expression is not currently supported to set the way the thematic map fields are set. If the set field expression is a conditional expression, such as "SmID & gt;" 100 ", then the thematic map produced will fail, and the Output Window will prompt" Thematic map update failed ".

  4. Value represented by a single point: The number of points or Density in the Dot Density Map reflects the thematic value corresponding to an area. In Dot Density Map, a point represents a certain value, and the number of points in an area multiplied by the value represented by the point is the thematic value corresponding to the area. Here, the numeric value expressed by one dot in the Dot Density Map is set by the "Numeric value represented by a single dot:" spin box.
    • You can enter a value in the text box to the right of the label control, or you can use the up and down spin buttons in the text box to adjust the data in the text box. As shown in the figure above, when the value entered in the text box to the right of "Value represented by a single point:" is 500,000, if the population of an area in 1994 is 1,000,000, the number of points distributed in the area is 10.
  5. Number of points included in the maximum value: The "Dots for Max Value:" digital display box is used to set the number of points included in the area of the maximum thematic value expressed by the point density. This parameter can be used to determine the Density of the point distribution on the map. The
    • user can enter a numeric value in the text box to the right of the label control, or adjust the data in the text box by using the up and down spin buttons in the text box. There is a negative correlation between the number of points included in the maximum value and the value represented by a single point. The larger the value represented by a single point is, the smaller the number of points included in the maximum value is, and vice versa. After setting any parameter, the system will automatically calculate the value of the other parameter. The user can also adjust the two parameter values according to the distribution of point density on the thematic map.
  6. Point style: You can set the dot style for all the points in a Dot Density Map.
    • Click the button to the right of the Dot Style: The style of the current Dot Density Map can be set in the pop-up Style Settings "window (see Point Symbol Style Settings" Window for details).
  7. Each Parameter Settings in the "Dot Density Map" window will be reflected to the corresponding thematic map layer in the current Map in real time, that is, WYSIWYG. You can also disable Enable Real-time Refresh by unchecking the Enable Instant Refresh "checkbox at the bottom of the dialog box. If the "Enable Instant Refresh" "check box is not checked, the user can click the" Apply "button at the bottom of the dialog box to apply the Parameter Settings in the dialog box to the current thematic map after completing the Parameter Settings.

Remark

  1. The Occupation density thematic map produced and modified by the user can be saved as a template, so as to be applied to the thematic map production of other layers. For details of Save as thematic map template, please refer to Save to Thematic Map Template Library .
  2. When Create Thematic Map in the Use Template mode, the user can directly select the saved template in the drop-down menu of the Template Drop-down Button to apply it to the production of other thematic maps.