Feature Description

In the "Graduated Color Thematic Map" window, users can modify various parameters of the graduated color thematic map to achieve effects that better meet their needs.

Steps

Select a graduated color thematic map layer in the Layer Manager, right-click the "Modify Thematic Map" button. The thematic map properties window will display settings information of the selected graduated color thematic map. Settings are identical for different types of vector layers when creating graduated color thematic maps. Taking the attribute window of polygon-based graduated color thematic maps as an example:

1. Thematic Map Layer: Displays the name of the currently displayed thematic map.
2. Expression: The "Expression:" combo box shows and sets the thematic variable for the current graduated color thematic map, which can be a property field or mathematical expression of the current layer.
   • Click the drop-down button of the "Expression:" combo box to view all property fields of the vector dataset used to create the current graduated color thematic map.
   • Select a thematic variable (single property field) from the dropdown. Users can also click "Expression..." to build field expressions in the "SQL Expression" dialog as thematic variables.
   • The graduated color thematic map will dynamically update based on modified thematic variables and refresh display effects.

   Note: For Oracle Plus or SQL Plus engine datasets, field expressions can only be field values or arithmetic operations (e.g., SmID or SmID+1). Conditional expressions like "SmID > 100" are unsupported and will cause thematic map creation failure with "Thematic map update failed" messages in the output window.

3. Segmentation Method: Use the drop-down button next to "Method:" to set segmentation approaches for thematic variables.
   • Equal Interval: Divides data into equal-length segments between max/min values based on user-defined segment count.
   • Square Root Interval: Performs equal interval segmentation on square roots of thematic values, then squares results to obtain actual breakpoints.
   • Standard Deviation Interval: Reflects deviations from mean value. Segments are created using standard deviation units, with center segment centered on mean. Segment count is automatically determined.
   • Logarithmic Interval: Applies equal interval segmentation to logarithmic values (base 10), then converts back using powers of 10.
   • Quantile Interval: Creates segments with equal record counts. Actual counts may vary slightly in last segment when unevenly divisible.
   • Custom Interval: User-defined segment length determines segment count automatically.
   • Natural Interval: Automatically groups data by maximizing differences between clusters.
4. Segments: The "Segments:" numeric box displays/sets the number of value ranges.
5. Interval: The "Interval:" numeric box sets segment length, effective only for custom interval method.
6. Rounding Precision: Drop-down provides 15 precision levels (10^7 to 10^-8). Determines decimal places for breakpoint values.
7. Label Format: Drop-down selects range display format from two predefined options.
8. Color: The "Color Scheme:" combo box sets color styles for segments.
   • Click the drop-down button to select color schemes that apply different colors to segments.
9. Merge/Split Segments: The lower list shows all segments for management:
   • Merge Button: Combines multiple consecutive selected segments (using Ctrl/Shift) into one. Disabled for non-consecutive selections.
   • Split Button: Divides a selected segment into two new segments.
10. Visibility Settings:
    • Toolbar eye icons control visibility for selected segments.
    • Individual segment eye icons toggle visibility per segment.
11. Symbol Style Settings: The middle toolbar modifies display styles for selected segments. Different vector types have varied style options:
    • Fill Style Button: Modifies fill patterns for polygon segments. Click segment fill icons or toolbar button to open "Fill Symbol Style Settings".
    • Line Style Button: Adjusts line styles. Access via toolbar or segment line icons ("Line Symbol Style Settings").
    • Point Style Button: Edits point markers. Use toolbar button or segment point icons ("Point Symbol Style Settings").
    • For batch modifications: Shift-select multiple segments, then use style buttons to open "Change Style" dialog.
12. Locate Subitems: Right-click selected subitems and choose "Locate" to highlight corresponding map objects. Map will zoom to objects if outside current view. Note: Requires layer selectable state.
13. Segment Values: The "Segment Value" column shows/modifies breakpoint values. Adjustments immediately update the thematic map.
14. Title: The "Title" column sets display names for segments.
15. All parameters take effect immediately unless "Enable Instant Refresh" is unchecked. When disabled, click "Apply" to manually update changes.

Notes

1. Thematic maps and modifications can be saved as templates for other layers. See: Save to Thematic Map Template Library.
2. When using null-value fields, segment parameters can still be set for template output purposes.
3. Apply saved templates via the "Template" dropdown when creating new thematic maps.