Feature Description
In nautical charts, the minimum scale of a feature refers to the smallest scale range at which the feature is displayed. When the chart's display scale is smaller than the feature's minimum scale, the feature will be hidden. This concept is particularly important in electronic charts for controlling feature visibility and ensuring map clarity.
Functions of minimum scale:
- Avoid information overload: Hide detailed features at small scales (e.g., when displaying large areas) to reduce visual clutter.
- Enhance display efficiency: Display only scale-appropriate features to improve chart rendering performance.
For example, according to IHO electronic chart specifications, a lighthouse may have a minimum scale of 1:50,000:
- The lighthouse appears when chart scale is 1:25,000
- The lighthouse disappears when scale changes to 1:100,000
The Update SCAMIN function ensures features comply with current scale display standards. The SCAMIN (minimum scale) field value determines feature visibility at different scales. This feature automatically adjusts SCAMIN values based on editing scales to maintain proper display, particularly useful in:
- Editing chart data to ensure correct feature display at specific scales
- Standardizing display criteria across chart groups
Steps
- Chart Tab -> Chart Data Processing group -> Update SCAMIN button to open Update the minimum scale of features dialog
- Select target chart group and click OK to automatically update minimum scale values
- Load chart group to window and view updated Minimum scale values through Properties in context menu
Tip: When viewing charts, configure minimum scale settings through display settings or nautical chart properties. See Filter Settings.
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