Modify graudated color thematic map

Instructions for use

In the 'Graduated Color Thematic Map' window, you can modify the various parameters of the graduated color thematic map to achieve a thematic map effect that better meets your needs.

Operation steps

In the Layer Manager, select a graduated color thematic map layer, right-click the "Modify Thematic Map" button, and the thematic map properties window that pops up displays the settings information of the selected graduated color thematic map. The settings for creating a graduated color thematic map with different types of vector layers are the same. Taking the attribute window for creating a graduated color thematic map based on a polygon layer as an example:

  1. Thematic Map Layer: Displays the name of the currently displayed thematic map.
  2. Expression: The "Expression:" combo box is used to display and set the thematic variable of the current graduated color thematic map, which is a property field of the current layer or a mathematical expression of property fields.
    • Click the drop-down button of the "Expression:" combo box, and the drop-down list displays all property fields of the vector dataset used to create the current graduated color thematic map.
    • In the drop-down list, select the thematic variable for the current graduated color thematic map layer (a single property field). Users can also click the "Expression..." item in the drop-down list to open the "SQL Expression" dialog box to construct a field expression as the thematic variable for the graduated color thematic map.
    • The current graduated color thematic map will immediately re-map based on the modified thematic variable and refresh the display effects.
    • Note: When creating a thematic map for data with Oracle Plus or SQL Plus engine types, the field expression can only be a field value or a field operation expression, such as (SmID) or (SmID + 1). Conditional expressions are currently not supported for setting thematic map fields. If the field expression set is a conditional expression, such as "SmID > 100", the created thematic map will fail, and the output window will prompt "Thematic map update failed".
  3. Classification Method: The drop-down button to the right of the "Method:" item is used to display and set the classification method for the thematic variable in the current graduated color thematic map. Users click the drop-down list of this combo box to select an appropriate classification method.
    • Equal Interval: Divides the range between the maximum and minimum values of all thematic values determined by the thematic variable into equal intervals based on the user-specified "Number of Classes". In an equal interval, each segment has an equal length.
    • Square Root Interval: Performs an equal interval classification on the square roots of the thematic values determined by the thematic variable. First, take the square roots of all thematic values, perform an equal interval classification to obtain the breakpoints of the processed data, then square these breakpoints to get the breakpoints for the corresponding thematic values, thus deriving the segmentation scheme.
    • Standard Deviation Interval: Reflects the deviation of an attribute value of objects from their average. First, calculate the mean and standard deviation of the thematic values determined by the thematic variable, then perform segmentation based on this. Each segment length in the standard deviation interval is one standard deviation, with the middle segment centered on the mean, and the left and right breakpoints differing by 0.5 standard deviations from the mean. The "Number of Classes" resulting from the standard deviation interval method is determined by the calculation result and cannot be controlled by the user.
    • Logarithmic Interval: Similar to the square root interval method, but instead of taking the square root of thematic values, it takes the logarithm (base 10) of the thematic values for equal interval classification. First, perform an equal interval classification on the logarithms of all thematic values to obtain breakpoints, then raise 10 to the power of these breakpoints to get the breakpoint values for the thematic values, thus deriving the segmentation scheme.
    • Quantile Interval: Each range segment contains an equal number of object counts. The "equal number" is determined by the user-specified "Number of Classes" and the actual object count in the layer used to create the graduated color thematic map. When divisible, each segment should have the same number of records, but when not divisible, the result may vary in the last segment.
    • Custom Interval: The user specifies the length of each segment, i.e., the "Interval Length", for segmentation. The "Number of Classes" is calculated by the system based on the specified interval distance and the maximum and minimum values of the thematic values, and cannot be controlled by the user.
    • Natural Interval: Automatically segments data based on differences between attribute values to maximize differences between groups.
  4. Classes: The "Number of Classes:" numeric display box is used to display and set the number of segments for classifying thematic values in the current graduated color thematic map, i.e., the number of range segments.
  5. Interval Length: The "Interval:" numeric display box is used to display and set the interval distance for segmentation in the current graduated color thematic map, i.e., the length of each range segment. This setting is only valid when the classification method is Custom Interval.
  6. Break Value Rounding Precision: The drop-down button to the right of the "Break Value Rounding Precision:" item is used to set the rounding precision for segment values. The program provides 15 rounding precision options: 10000000, 1000000, 100000, 10000, 1000, 100, 10, 1, 0.1, 0.001, 0.0001, 0.00001, 0.000001, 0.0000001, 0.00000001. For example, when the break value rounding precision is set to 0.1, segment values are rounded to one decimal place; when set to 1000, segment values are rounded to the nearest thousand.
  7. Segment Title Format: The drop-down button to the right of the "Label Format:" item is used to specify the format for expressing the value range of each segment. The system provides two segment title formats, selectable via this drop-down button.
  8. Color: The "Color Scheme:" combo box is used to display and set the color style for each range segment in the current graduated color thematic map.
    • Click the drop-down button to the right of the "Color Scheme:" combo box, and in the pop-up drop-down list, select a color to assign different colors to each range segment of the graduated color thematic map based on the chosen color scheme.
  9. Merge or Split Range Segments: The list at the bottom of the tab lists all range segments, allowing users to merge or split them as needed.
    • The merge button combines multiple selected consecutive range segments (using Ctrl or Shift keys) into one segment. The merged segment's value range is the union of all merged segments. If no segment, only one segment, or non-consecutive segments are selected, this button is unavailable.
    • The split button divides a selected range segment into two new segments.
  10. Visibility Settings:
    • Click the visibility icon button on the toolbar to control the visibility of objects corresponding to all selected range segments in the list.
    • Click the visibility icon for each range segment item to control the visibility of objects in that segment.
  11. Symbol Style Settings: The toolbar in the middle of the "Graduated Color Thematic Map" window can be used to set the display style for selected range segments in the list. Users can also click the marker style icon for each range segment item to open the resource list for bounds settings of the corresponding map segment. The functionality of symbol style settings buttons varies for graduated color thematic maps created from different types of vector datasets.
    • The fill style button sets the fill style for objects corresponding to all selected range segment items in the current graduated color thematic map. Click this button or the face marker style icon for each range segment item to open the "Styles" window (see Fill Symbol Style Settings for details), allowing users to set the fill style for polygon objects in selected segments.
    • The line style button sets the marker style for line objects in all selected range segments of the current graduated color thematic map. Click this button or the line marker style icon for each range segment item to open the "Styles" window (see Line Symbol Style Settings for details), allowing users to set the marker style for line objects in selected segments.
    • The point style button sets the point marker style for objects in all selected range segments of the current graduated color thematic map. Click this button or the point marker style icon for each range segment item to open the "Styles" window (see Point Symbol Style Settings for details), allowing users to set the marker style for point objects in selected segments.
    • When modifying the style of multiple thematic map sub-items, hold the Shift key to select the sub-items, then click the "Style" setting button on the toolbar to open the "Change Style" dialog box for batch modifications. See Change Style for details.
  12. Sub-item Positioning: Select one or more thematic map sub-items in the list, right-click, and choose the "Position" option to highlight corresponding objects in the map. If positioned objects are within the current map visible bounds, they are directly highlighted; if not, the map scale is maintained to center and display the positioned objects. Note: To use thematic map sub-item positioning, set the layer to selectable state.
  13. Ranges: The "Segment Value" column in the range segment list displays and sets the numerical value of each segment's breakpoint (the end point of the segment). Each numeric display box corresponds to a breakpoint, and changing the value will be immediately reflected in the current graduated color thematic map layer.
  14. Title: The "Title" column in the range segment list displays and sets the title for each range segment.
  15. All parameters in the "Graduated Color Thematic Map" window are immediately reflected in the corresponding thematic map layer in the current map, achieving WYSIWYG. Users can also uncheck the "Enable Instant Refresh" checkbox at the bottom of the dialog to disable real-time refresh. If unchecked, after setting parameters, click the "Apply" button at the bottom to apply the parameters to the current thematic map.
Notes:
  • Both created and modified graduated color thematic maps can be saved as templates for application to thematic map creation in other layers. For saving as a thematic map template, see: Save to Thematic Map Template Library.
  • If the selected field in the expression is empty, parameters such as number of segments, ranges, and sub-item styles can still be set, suitable for output as a thematic map template.
  • When creating a thematic map using a template, users can directly select a saved template from the drop-down menu of the "Template" drop-down button to apply it to the creation of other thematic maps.

Related topics

Create graduated color thematic map