Inserting the Topo North Arrow element (Maritime Charting)

The Topo North Arrow is a declination diagram that can be placed in the page layout and represents the three norths:

• Grid north (GN)—The north established by using the vertical grid lines on the map and generated using the automatic calculation of grid north based on the centerpoint of the current active data frame. This arrow displays with a minimum angle value of ± 2 degrees tilt if the value specified is below the minimum value.
• Magnetic north (MN)—The direction to the north magnetic pole, as indicated by the north-seeking needle of a magnetic instrument. It is generated using the automatic calculation of magnetic north based on the centerpoint of the current active data frame and the current date. It is symbolized by a line ending with half an arrowhead. This arrow displays with a minimum angle value of ± 3 degrees tilt if the value specified is below the minimum value.
• True north—A line from any point on the earth's surface to the North Pole. All lines of longitude are true north lines. It is represented by a star at the end of a line. In this surround element, true north displays as a vertical line with a rotation of zero.

This element can be converted to a graphic to allow alterations. You can ungroup the element and alter it by selecting the element, clicking Convert To Graphics, then clicking Ungroup to ungroup the elements. Perform the required edits, then regroup the elements by selecting them all and clicking Group. However, once you convert this element to a graphic, it becomes a group of lines, and text and is no longer configurable as a north arrow.

Etapes :

1. Start ArcMap.
2. Load data into the map or open an existing map document.
3. Verify that the map is in layout view.
4. On the main menu, click Insert > Topographic > Topo North Arrow.

   A default north arrow is added to the layout. Continue with the next steps if you want to modify the properties for this element.

5. Double-click the north arrow element.

   The Topo North Arrow Properties dialog box appears.

6. Click the Topo North Arrow tab if necessary.

   The Topo North Arrow tab appears.
7. if necessary, click the Date drop-down arrow to choose the declination date you want to use.

   Any date between 2005 and 2014 is currently supported.

8. Uncheck the Update dynamically check box if you want to modify the element properties.

   When this check box is checked, the magnetic north, grid north, mils, and UTM zone are calculated using the current date and centerpoint of the active data frame.

9. Perform the following for both the Magnetic North and Grid North area options:
   1. Click West or East for your north arrow.
   2. Type or select the number of degrees you want to use in the Degrees text box.
      Remarque :

      Modifying the value automatically sets the Mils value. You can also override the default Mils calculation by typing a value in the Mils text box.

   3. Type or select the number of minutes you want to use in the Minutes text box.
      Remarque :

      Modifying the value automatically sets the Mils value. You can also override the default Mils calculation by typing a value in the Mils text box.

10. To modify the UTM zone, click the Properties button next to the Zone text box in the UTM area.
    Remarque :

    Modifying the UTM Zone parameter automatically populates the Grid North Degrees, Minutes, and Mils values. This property is useful for determining the grid north on a map with a UTM zone that differs from the centerpoint of the current map (that is, for maps with two UTM zones).

    The Spatial Reference Properties dialog box appears.

11. Click Select.

    The Browse for Coordinate System dialog box appears.

12. Navigate to the coordinate system you want to use.
    Remarque :

    You must choose a projected coordinate system.

13. Click Add.

    The Spatial Reference Properties dialog box appears.

14. Click OK.

    The Topo North Arrow Properties dialog box appears.

15. Click OK.