Modify Graduated Color Thematic Map

Feature Description

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

Operational Steps

Select a graduated color thematic map layer in the Layer Manager, right-click the "Modify Thematic Map" button. The thematic map properties window that pops up displays the settings information for the selected graduated color thematic map. The settings are the same when producing segmented thematic maps for different types of vector layers. Taking the properties window for producing segmented thematic maps 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 for the current graduated color thematic map, which is a certain property field or a mathematical expression of property fields of the current layer. The default here displays the field alias. You can switch to the field name in the File tab -> Options group. For details, refer to the Preference Settings document.
    • Click the drop-down button of the "Expression:" combo box; the drop-down list that pops up lists 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) for the current graduated color thematic map layer. Users can also click the "Expression..." item in the drop-down list and build a field expression in the popped-up "SQL Expression" dialog box to serve 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 effect.
    • Note: When creating thematic maps for data with engine types such as Oracle Plus or SQL Plus, the field expression can only be a field value or a field operation expression, such as (SmID) or (SmID + 1). Currently, setting the thematic map field using conditional expressions is not supported. If the set field expression 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. Segmentation Method: The drop-down button on the right side of the "Method:" item is used to display and set the segmentation method for the thematic variable in the current graduated color thematic map. Users click the drop-down list of this combo box to select a suitable segmentation method.
    • Equal Interval: Segments based on the maximum and minimum values among all thematic values determined by the thematic variable into equal intervals according to the user-defined "Number of Classes". In the equal interval method, each segment has an equal length.
    • Square Root Interval: Performs equal interval segmentation on the square roots of the thematic values determined by the thematic variable. First, take the square roots of all thematic values, then perform equal interval segmentation to obtain the segmentation points of the processed data. Then, square the values of these segmentation points to obtain the corresponding segmentation points for the thematic values, thus obtaining the segmentation scheme for the thematic values.
    • Standard Deviation Interval: Reflects the deviation of an attribute value of each object from its average. First, calculate the average and standard deviation of the thematic values determined by the thematic variable, and then perform segmentation based on this. The length of each segment in the standard deviation interval is one standard deviation. The middle segment is centered on the average, with the left and right segmentation points differing from the average 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, the difference is that the square root method takes the square root of the thematic value, while the logarithmic interval method takes the logarithm of the thematic value, i.e., performs equal interval segmentation on the base-10 logarithm of the thematic values. First, perform equal interval segmentation on the logarithms of all thematic values to obtain the segmentation points of the processed data. Then, using 10 as the base and the values of these segmentation points as exponents, calculate the power to obtain the values of the corresponding segmentation points for the thematic values, thus obtaining the segmentation scheme.
    • Quantile Interval: Each range segment has an equal number of objects. The "equal number" is determined by the user-specified "Number of Classes" and the actual object count in the layer used to produce the segmented thematic map. When divisible equally, the number of records in each segment should be the same. However, when records are not divisible equally, there will be discrepancies in the last segment of the segmentation result.
    • Custom Interval: The user specifies the length of each segment, i.e., the "Single Segment Length" for segmentation. 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: Can automatically segment based on differences between data attribute values, maximizing the differences between groups.
  4. Classes: The "Number of Classes:" numeric display box is used to display and set the number of segments for segmenting the thematic values in the current graduated color thematic map, i.e., the number of range segments.
  5. Single Segment Length: The "Interval:" numeric display box is used to display and set the segmentation interval distance for the current graduated color thematic map, i.e., the length of each range segment. This setting is only effective when the segmentation method is Custom Interval.
  6. Segment Rounding Precision: The drop-down button on the right side of the "Segment Rounding Precision" item is used to set the rounding precision for 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 segment rounding precision is set to 0.1, segment values are rounded to one decimal place; when set to 1000, segment values are rounded to three digits before the decimal point.
  7. Segment Title Format: The drop-down button on the right side 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, which can be selected via this drop-down button.
  8. Color Scheme: 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 on the right side of the "Color Scheme:" combo box, and select a color scheme from the pop-up drop-down list to assign different colors to each range segment of the graduated color thematic map based on the selected color scheme.
  9. Merge or Split Range Segments: The list at the bottom of the tab lists all range segments. You can merge and split range segments as needed.
    • The Merge button is used to merge multiple selected consecutive range segments (can be used with Ctrl or Shift keys) into one range segment. The value range of the merged segment is the union of the value ranges of all merged segments. If no segment, only one segment is selected, or the selected multiple segments are not consecutive, this button is unavailable.
    • The Split button is used to split a selected range segment into two new range 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 range segment list.
    • Click the visibility icon in each range segment item to control the visibility of objects corresponding to that range 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 the selected range segments in the list. Users can also click the marker style icon in each range segment item and set the map style for the corresponding segment in the popped-up resource list. The functions of the symbol style settings buttons differ for graduated color thematic maps created from different types of vector datasets.
    • The Fill Style button is used to set the fill style for objects corresponding to all selected range segment items in the current graduated color thematic map. Click this button, or click the polygon marker style icon in each range segment item, to pop up the "Styles" window (for specific operations, refer to Fill Symbol Style Settings). Users can set the fill style for polygon objects corresponding to the selected range segment as needed.
    • The Line Style button is used to set the style for 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 pop up the "Styles" window (for specific operations, refer to Line Symbol Style Settings). Users can set the marker style for line objects corresponding to the selected range segment as needed.
    • The Point Style button is used to set the point marker style for 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 pop up the "Styles" window (for specific operations, refer to Point Symbol Style Settings). Users can set the marker style for point objects corresponding to the selected range segment as needed.
    • When needing to modify the styles of multiple thematic map sub-items, you can hold down the Shift key to select the thematic map sub-items whose style you want to modify, then click the "Style" setting button on the toolbar. The "Change Style" dialog box pops up, where you can select the items to modify for batch modification. For specific operations, please refer to: Change Style.
  12. Sub-item Locating: Select one or more thematic map sub-items in the thematic map sub-item list, right-click the mouse, and select the "Locate" option to highlight the corresponding objects in the map. If the located object is within the current map's visible bounds, the object is directly highlighted; if the located object is not in the current map, the map scale will be maintained, and the display will be centered on the located object. Note: When using the thematic map sub-item locating function, the layer needs to be set to a selectable state.
  13. Ranges: The "Segment Value" column in the range segment list is used to display and set the numerical value of each range segment's segmentation point (the endpoint of that segment) (as shown in the figure above). Each numeric display box corresponds to a segmentation point. The numerical value of a segmentation point can be changed via this numeric display box, and the changed result will be immediately reflected on the current graduated color thematic map layer.
  14. Title: The "Title" column in the range segment list is used to display and set the title of each range segment.
  15. All parameters in the "Graduated Color Thematic Map" window are immediately reflected 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" checkbox at the bottom of the dialog box. If the "Enable Instant Refresh" checkbox is not checked, after completing all parameters, users can click the "Apply" button at the bottom of the dialog box to apply the parameters in the dialog box to the current thematic map.
Notes:
  • Both created and modified graduated color thematic maps can be saved as templates for application in thematic map creation for other layers. For saving as a thematic map template, please refer to: Save to Thematic Map Template Library.
  • If the field selected at the expression is empty, you can still set related parameters such as number of classes, ranges, and sub-item styles, which is applicable for output as a thematic map template.
  • When creating a thematic map using the template method, users can directly select a saved template from the drop-down menu of the "Template" drop-down button and apply it to the creation of other thematic maps.

Related Topics

Create a New Graduated Color Thematic Map