Modify Graudated Color Thematic Map

Feature Description

You can modify various parameters of the graduated color thematic map in the "graudated color thematic map" window to achieve thematic map effects that better meet 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 will display the settings of the selected graduated color thematic map. The settings for different types of vector layer production of segmented thematic maps are the same. Take the properties window for production of segmented thematic maps based on a polygon layer as an example:

  1. Thematic Map Layer: Displays the name of the currently presented thematic map.
  2. Expression: The "expression:" combo box is used to display and set the thematic variable of the current graduated color thematic map, that is, a property field of the current layer or a mathematical expression of a property field. The default displays the field alias. You can switch to the field name in the File tab -> Options group. For details, see the Preferences document.
    • Click the drop-down button of the "expression:" combo box, and the drop-down list shows 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 (a single property field) of the current graduated color thematic map layer. Users can also click the "expression..." item in the drop-down list, and in the pop-up "SQL Expression" dialog, construct a field expression as the thematic variable of the graduated color thematic map.
    • Reset Ranges after Expression Changed: If this check box is checked, after changing the expression, the program will automatically reset the range values, and the graduated color thematic map will be re-mapped in real time according to the modified range values, and the display effects will be refreshed. If unchecked, the range values will not be reset when the expression is changed. After switching the expression, if the range values cannot correspond to the original values, the program will render the map with the default style.
    • Note: For data of Oracle Plus and SQL Plus engine types, when creating a thematic map, the field expression can only be a field value or a field operation expression, such as (SmID) or (SmID + 1), etc. Currently, setting thematic map fields by conditions expression is not supported. If the set field expression is a conditional expression, such as: "SmID > 100", then the thematic map creation will fail, and the output window will prompt "Thematic map update failed".
  3. Segmentation Method: The drop-down button on the right of the "method:" item is used to display and set the segmentation method of the thematic variable in the current graduated color thematic map. Click the drop-down list of this combo box to select an appropriate segmentation method.
    • Equal Interval: Segments the data into equal intervals based on the maximum and minimum values of all thematic values determined by the thematic variable, according to the user-specified "number of classes". In equidistant intervals, each segment has an equal length.
    • Square Root Interval: Performs equidistant interval on the square root of the thematic values determined by the thematic variable. First, take the square root of all thematic values, then perform equidistant interval to obtain the breakpoints of the processed data. Then square these breakpoints to get the breakpoints of the corresponding thematic values, thus obtaining the segmentation scheme for the thematic values.
    • Standard Deviation Interval: Reflects the deviation of a certain attribute value of each object from its mean. First, calculate the mean and standard deviation of the thematic values determined by the thematic variable, and then segment based on them. Each segment length in standard deviation interval is one standard deviation. The middle segment is centered on the mean, with the left and right breakpoints differing from the mean by 0.5 standard deviations. The "number of classes" obtained by the standard deviation interval method is determined by the calculation result and cannot be controlled by the user.
    • Logarithmic Interval: Basically the same as the square root interval method, except that the square root method takes the square root of the thematic values, while the logarithmic interval method takes the logarithm of the thematic values, i.e., performs equidistant interval on the base-10 logarithm of the thematic values. First, perform equidistant interval on the logarithms of all thematic values to obtain the breakpoints of the processed data. Then use 10 as the base and these breakpoints as exponents to obtain the corresponding breakpoints of the thematic values, thus obtaining the segmentation scheme.
    • Quantile Interval: Each range segment contains an equal number of objects. The "equal number" is determined by the user-specified "number of classes" and the actual number of objects in the layer used for production of segmented thematic maps. If the number of objects can be evenly divided, the records in each segment should be the same. However, when the records cannot be evenly divided, the segmentation result may vary in the last segment.
    • Custom Interval: The user specifies the length of each segment, i.e., the "single segment length". The "number of classes" is calculated by the application 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 based on the differences between data attribute values, maximizing the differences between groups.
  4. Classes: The "Classes:" number display box is used to display and set the number of segments for the thematic variable in the current graduated color thematic map, i.e., the number of range segments.
  5. Interval: The "Interval:" number display box is used to display and set the interval distance of the graduated color thematic map segmentation, i.e., the length of each range segment. This setting is only valid when the segmentation method is Custom Interval.
  6. Range Rounding Precision: The drop-down button on the right of the "Range rounding precision:" item is used to set the rounding precision of segment values. The program provides 15 rounding precisions: 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 range 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 thousands place.
  7. Label Format: The drop-down button on the right of the "label format:" item is used to specify the format for expressing the value range of each range segment. The system provides two label formats, which can be selected through this drop-down button.
  8. Color Scheme: The "color scheme:" combo box is used to display and set the color style of each range segment in the current graduated color thematic map.
    • Click the drop-down button on the right of the "color scheme:" combo box, and select a color scheme from the drop-down list to assign different colors to each range segment of the current graduated color thematic map.
  9. Segment Title: The Segment Title text box is used to display and set the title of the current graduated color thematic map. You can directly enter or modify the title content.
  10. Merge or Split Range Segments: The list at the bottom of the tab lists all range segments. You can merge or split range segments as needed.
    • The merge button is used to merge multiple selected consecutive range segments (you can use the Ctrl or Shift key) into one range segment. The value range of the merged segment is the union of the value ranges of all merged segments. If no or only one segment is selected, or if multiple selected segments are not consecutive, this button is disabled.
    • The split button is used to split a selected range segment into two new range segments.
  11. Visibility Settings:
    • Click the visibility icon button in the toolbar to control the visibility of objects corresponding to all selected range segments in the list.
    • Click the visibility icon in each range segment item to control the visibility of objects corresponding to that range segment.
  12. Symbol Style Settings: The toolbar in the middle of the "graudated color thematic map" window can be used to set the display style of the selected range segment in the segmentation range list. Users can also click the marker style icon in each range segment item to set the map style corresponding to the bounds settings in the resource list. The functions of the symbol style settings buttons vary depending on the vector dataset type used to create the graduated color thematic map.
    • The fill style button is used to set the fill style of objects corresponding to all selected range segments in the current graduated color thematic map. Click this button, or click the polygon marker style icon in each range segment item, to open the "Styles" window (for specific operations, see Fill Style Settings). Users can set the fill style for the selected range segments as needed.
    • The line style button is used to set the line objects corresponding to all selected range segments in the current graduated color thematic map. Click this button, or the line marker style icon in each range segment item, to open the "Styles" window (for specific operations, see Line Style Settings). Users can set the marker style for the selected range segments as needed.
    • The point style button is used to set the point marker style of objects corresponding to all selected range segments in the current graduated color thematic map. Click this button, or the point marker style icon in each range segment item, to open the "Styles" window (for specific operations, see Point Style Settings). Users can set the marker style for the selected range segments as needed.
    • When you need to modify the style of multiple thematic map sub-items, you can hold down the Shift key to select the thematic map sub-items to modify, then click the "Style" setting button in the toolbar to open the "Change Style" dialog. You can select the items to modify for batch modification. For specific operations, see: Change Style.
  13. Sub-Item Positioning: Select one or more thematic map sub-items in the thematic map sub-item list, right-click, and select the "Positioning" option to display the corresponding objects highlighted in the map. If the positioned object is within the current map's visible bounds, the object is directly highlighted; if the positioned object is not in the current map, the map scale will be maintained and the positioned object will be displayed centered. Note: When using the thematic map sub-item positioning function, the layer must be set to selectable.
  14. Ranges: The "Range Value" column in the range segment list is used to display and set the value of the breakpoint (the end point of the segment) for each range segment (as shown in the figure above). Each number display box corresponds to a breakpoint, and the breakpoint value can be changed through this number display box. The changed result will be reflected in real time on the current graduated color thematic map layer.
  15. Title: The "Title" column in the range segment list is used to display and set the title of each range segment.
  16. All parameters in the "graudated color thematic map" window will be reflected in real time on the corresponding thematic map layer in the current map, achieving WYSIWYG. Users can also disable real-time refresh by unchecking the "Enable instant refresh" check box at the bottom of the dialog. If the "Enable instant refresh" check box is unchecked, after completing the parameter settings, users can click the "Apply" button at the bottom of the dialog 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 production of other layers. For saving as a thematic map template, see: Save to Thematic Map Template Library.
  • If the field selected in the expression is null, you can still set related parameters such as number of classes, ranges, and sub-item styles. This is suitable for output as a thematic map template.
  • When creating a thematic map using the template method, users can select a saved template from the drop-down menu of the "Template" button and apply it to the production of other thematic maps.

Related Topics

New Graudated Color Thematic Map