Every nautical chart has a compass rose to delineate true north and magnetic north, as well as assist with angles for orientation, bearing, and traversing routes. In most situations, the compass rose will be represented by the TidesAndVariationsP feature class. However, the representation rule can be applied to any point feature class, as long as it has fields that contain the attributes required to calculate the rotation of the magnetic north section of the rose. For the compass rose to be portrayed, it needs to be associated with a point feature. In some cases, the TidesAndVariationsP feature class may not contain any features that can be used to display a compass rose on a chart.
The following steps outline how to add a new point feature to the TidesAndVariationsP feature class.
- Start ArcMap.
- Open the product map document.
- Identify whether there are any data points in the TidesAndVariationsP feature class.
- Right-click the feature class and click Open Attribute Table.
If there are no data points with an FCSubtype value of MAGVAR, continue with this topic. If the feature class contains MAGVAR objects, skip this topic and move on to 'Calculating magnetic variation and annual change for compass roses'.
- Add the Production Editing toolbar if necessary by clicking Customize > Production > Toolbar Settings > Nautical Chart Production.
- Click OK on the ArcMap Settings Change Warning dialog box.
- Click the Production Start Editing button on the Production Editing toolbar.
- Right-click the Create tab on the Manage Features window, point to Load Templates From View, then click PaperChartView.
The template will change to show subtypes in the Create tab.
- Identify a place on the chart that is not too cluttered to add the rose.
- In the Manage Features window, scroll to the TidesAndVariationsP layer and click the MAGVAR_MAGNETICVARIATION subtype.
The Point tool is automatically enabled, and your cursor changes.
- Click to add a new point. If the exact coordinates of the rose are known, right-click the data frame and click Absolute X,Y, then type the coordinates.
- Click the Update tab on the Manage Features window.
- On the Create Attributes window, type the year in the RYRMGV field.
- Click Apply to update the feature attribute.
- If necessary, repeat steps 9 through 14 to add more compass rose points.
- Click the Save Edits button on the Production Editing toolbar.
- Click the Stop Editing button on the Production Editing toolbar.
The geodatabase becomes uneditable. If you have made edits, you will be prompted to save the changes if you want.