Regardless of whether the layer type is vector, raster, or image, you can set the layer's transparency, order, visible scale range, and filter displayed objects.
Setting Layer Transparency
Transparency is a display property of the layer. It can be set in the Transparency: numeric adjustment box in the Layer Properties panel.
The transparency numeric adjustment box can be used to set the transparency level of the current layer. You can also directly enter a transparency value to preview the result in real-time. The default transparency value is 0, which means the layer is completely opaque. As the value increases, the layer becomes more transparent. When the transparency value is set to 100, the layer is completely transparent. The transparency value must be an integer between 0 and 100.
Adjusting Layer Order
The stacking order of layers directly affects the map display effects. Generally, there are two rules for the stacking order of map layers:
- Based on the object's map bounds, from top to bottom: small -> medium -> large;
- Based on the layer type, from top to bottom: text/point -> line/region.
Note:The above stacking order rules are only a general recommended order. Other layer sort orders may exist depending on different map production requirements.
The two maps below show the map effects before and after placing a specific layer (RoadLine) at the bottom. From these two maps, the importance of the layer stacking order to map display is clearly evident.
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| Map display effects before layer adjustment | Map display effects after layer adjustment |
As can be seen from the figure above, a line layer seems to have "disappeared" from the map. It has not been removed but moved to the bottom layer and displayed at the bottom.
There are mainly two ways to adjust the layer order:
Note:Direct dragging requires that the layer node is set to be draggable. The Layer Manager toolbar -> Layer Control drop-down menu -> Layer nodes can be dragged controls whether the layer order can be changed by dragging.
- Using Layer Control
Operation steps:
- If there is an open map in the current workspace, open the Layer Control dialog box using one of the following steps.
- In the Layer Manager, click the Layer Control button;
- In the Layer Manager, right-click any layer and select the Layer Control command.
- In the Layer Control dialog box, select one or more layers, and then use the buttons in the toolbar such as Bring to Top, Move Up, Move Down, and Send to Bottom to adjust the layer order. For detailed information about Layer Control, please refer to Layer Control.
- If there is an open map in the current workspace, open the Layer Control dialog box using one of the following steps.
- Direct Dragging
Operation steps:
- In the Layer Manager, select one or more layers.
- Drag the selected layers to the target position.
- Release the mouse.
Layer Blend Mode
Blend Mode is used to set the overlay method between two layers. It calculates the color of the upper layer with the color of the lower layer to obtain different shading effects. The specific effect depends on the selected mode.
The available modes are as follows:
| Mode Category | Mode Name | Description |
| Normal Mode | Normal | No change is made to the layer color. This is the default blend type. |
| Darken | Darken | Compares the layer color with the color of the layer below and uses the minimum RGB value of the two layers as the final rendering color. |
| Multiply | Multiplies the layer color by the color of the layer below, which usually results in a darker final rendering color. | |
| Color Burn | Darkens the color of the layer below. White is not affected. | |
| Linear Burn | Adds the layer color to the color of the layer below and then subtracts 1. | |
| Lighten | Lighten | Compares the layer color with the color of the layer below and uses the maximum RGB value of the two layers as the final rendering color. |
| Screen | Subtracts the white areas of the layer and the layer below, then multiplies the results. | |
| Color Dodge | Reduces the contrast between the layer and the layer below, increasing the brightness of the layer below. Black is not affected. | |
| Linear Dodge | Adds the brightness of the layer and the layer below. Black is not affected. | |
| Contrast | Overlay | Multiplies areas of the layer below with color values less than 0.5 by the blend layer. Areas greater than 0.5 use the Screen mode for the blend layer. |
| Soft Light | The algorithm is the same as the Overlay mode but reduces the color contrast of the layer. | |
| Hard Light | Areas of the layer with color values less than 0.5 are multiplied by the layer below. Areas greater than 0.5 use the Screen mode. | |
| Vivid Light | A combination of Color Dodge and Color Burn. | |
| Linear Light | Brightens areas where the blend layer's color brightness is higher than 0.5 and darkens areas where it is lower than 0.5. | |
| Pin Light | If the current layer color is lighter than 50% gray, pixels darker than the current layer color are replaced. If the current layer color is darker than 50% gray, pixels lighter than the current layer color are replaced. | |
| Difference | Difference | Subtracts the color value of the lower layer from the color value of the upper layer, divides the result by 2, and then adds the color value of the lower layer. This results in an effect where the upper layer's color is opposite to the lower layer's color. |
| Subtract | Subtracts the color of the upper layer from the color of the lower layer to obtain the resulting color. |
Note:When the layer blend mode is set to Multiply, it is not recommended to enable "the tile background is transparent" when generating raster tiles for the map; otherwise, the tiles may display abnormally (white images).
Setting Fill Mode
The fill mode is used to control the drawing method of symbols. It supports global mode and object mode, enriching the expression of symbols in the map.
Application Example
Case Description: Taking the fill mode of all prefecture-level cities in Sichuan Province as an example, you can set the symbol mode for area objects to global mode or object mode to enrich the symbol expression.
Data Description: Region dataset.
Main Operation Steps
- Select the area layer in the Layer Manager that needs symbols. In the Styles tab -> Fill Style group -> Symbol drop-down box, select the desired symbol style.
- Select the area layer in the Layer Manager that needs the fill mode set. Right-click and select Layer Properties.
- In the Layer Properties window, under Display Control -> Fill Mode, select Global Fill or Object Fill.
- Depending on the selected fill mode, the resulting effects differ, as shown below:
- Left image Global Mode: Starts drawing from the top-left corner of the entire layer, filling the whole layer with the symbol.
- Right image Object Mode: Starts drawing from the top-left corner of each object, filling each individual object in the layer with the symbol.
Note:For CAD datasets, which may contain point, line, and area objects, the fill mode only applies to the area objects within them.
Setting Layer Visible Scale Range
You can set the visible scale range in the Layer Properties or use a filter to filter objects in the layer.
Minimum Visible Scale
Minimum Visible Scale: This combo box is used to set the minimum visible scale for the current layer. After setting the minimum visible scale, if the map scale is smaller than the set minimum visible scale, the layer will not be visible.
Maximum Visible Scale
Maximum Visible Scale: This combo box is used to set the maximum visible scale for the current layer. After setting the maximum visible scale, if the map scale is no less than the set maximum visible scale, the layer will not be visible.
Note:The drop-down button on the right provides different scale options in different situations:
- If the current map has fixed scales set, the drop-down button provides fixed scale options;
- If the current map does not have fixed scales set, the drop-down button provides eight basic scale options from 1:5000 to 1:1000000;
- If you have customized scale values in the numeric adjustment box next to Maximum/Minimum Visible Scale, the drop-down button will record your customized values based on the first two situations for repeated use;
Display Field
Used to set the display field for vector objects in the Properties panel. After setting, when you select a vector object on the map, you can directly view the attribute values of the specified display field in the Object Properties panel, making it easier to distinguish object types based on attributes. By default, the name field in the layer is used. If there is no name field, the text field is used. If there is no text field, the SmID field is used.
- If an invalid expression field is set, it will be displayed as the invalid value "Null" when viewed in the Object Properties panel.
Raster/Image Title
When the layer is a raster layer or an image layer, you can set the raster and image title. You can directly enter or modify the title content.
Display Filter
Used to set the display filter for the current layer, filtering which objects in the layer can be displayed and which cannot. This allows users to display features of interest as needed while filtering out features that do not need to be displayed temporarily.
You can enter an SQL expression as the filter in the Display Filter text box. Press the Enter key to apply the layer filter, making the objects that satisfy the filter visible. You can also click the button to the right of the text box and construct the filter expression in the SQL Expression dialog box that appears. After setting, click the OK button to apply the layer filter, making the objects that satisfy the filter visible.
Click the Join Attribute Table... button to open the "Join Attributes" dialog box. Connect an external table through a join field, and then build a filter involving fields from the external table to filter and display the content in the layer.
Related Topics
Setting Vector Layer Properties
Setting Raster Layer Properties
Setting Image Layer Properties