View - Grid

Show a grid of horizontal and vertical lines that may be used as a guide when editing. Grids are often used with Snap to precisely locate mouse clicks. The default color for grids is set in Tools - Options .

 

Usage with drawings, images, surfaces, labels and maps

 

In drawings, images, surfaces, labels and maps the View - Grid dialog provides the following options:

 

Show Grid

Check box to show grid.

From / To

The beginning and end X and Y values the grid should span.

Spacing

X and Y spacing of grid lines.

(Units box)

Choose units to be used.

Same Spacing

Check so that any change in X spacing will update Y spacing as well and vice versa. Use if the same X and Y grid spacing is desired.

Segments

The number of coordinates to use per grid line. More segments will allow for smoother curves if lines created with grids are ever projected.

Style

Graphics style used to show grid lines.

Size

Width of line in printer's points to use for the grid line.

Suggest

Load suggested defaults for the current view.

Create

Create actual line objects in the drawing for the grid. Use carefully, since every press of the Create button will create another set of lines.

 

Default settings for the above options will be presented that cover the current view with a grid, using what are likely to be reasonable settings for stepping.

 

If a very large number of grid cells (greater than 10000) would be created given the specified settings, Manifold will ask for a confirmation in case of error.

 

Usage with forms and print layouts

 

In forms and print layouts, the Grid dialog provides a simpler set of controls, since the grid is automatically created over the entire layout or form:

 

Show Grid

Check box to show grid.

Step by X

X (horizontal) spacing of grid lines in the given units.

Step by Y

Y (vertical) spacing of grid lines in the given units.

(Units box)

Choose units to be used.

 

Creating Grids as Objects

 

The grid that appears when the Show Grid box is checked is not part of any layer. It is something created by the system and overlaid upon the map window. It does not really exist and cannot be selected or otherwise manipulated. The default grid color is set by an option in Tools - Options .

 

We frequently will want to create actual objects, lines, in the form of the grid to allow us to better manipulate the grid in graphics arts effects. For example, we might wish to position the grid in a drawing layer in a map so that it is above some layers (oceans objects) and below others (continents). Alternately, we might want to select some of the lines that make up the grid and delete them so we have a grid in some places but not in others. This is of interest sometimes to create a proper appearance when using "interrupted" projections.

 

To create line objects, set up the grid as desired in the View - Grid dialog and then press the Create button. The grid will be created in the active drawing as line objects. These may then be manipulated like any other lines. In maps it is often convenient to first create a new blank drawing with a right click on a layer tab and using Add - New Drawing, to rename the new drawing "grid" and to then create the grid in that layer.

 

Example

 

images\sc_graticule_01.gif

 

If we create a grid on a world map (seen in Latitude / Longitude projection) it will overlay all objects in the map. The grid shown extends from -180 to 180 degrees longitude and from -70 to 70 degrees latitude using a spacing of 10 degrees.

 

We can use Add - New Drawing to create a new drawing and then create a grid by pressing the Create button in the View - Grid dialog.

 

images\sc_graticule_02.gif

 

To see the new set of grid lines, we uncheck the Show Grid box in the dialog (otherwise, the grid shown by the system will precisely overlay and thus hide the new grid just created). We can move the new drawing to a layer below the world map drawing and change the color of the lines in the grid.

 

The Difference between Graticules and Grids

 

Graticules are always expressed in geographic coordinates (latitude and longitude) while grids are expressed in the native X and Y coordinates of the coordinate system of the component. For components using the Latitude / Longitude "non-projection", both graticules and grids will appear as a grid of horizontal and vertical straight lines.

 

In projected coordinate systems, graticules will be created as curved lines (if necessary) to parallel the curved form of meridians of longitude or parallels of latitude in the projection. Grids, however, will always appear as a grid of horizontal and vertical straight lines.

 

images\sc_graticule_and_grid.gif

 

In the image above a drawing of a world map is shown in Robinson projection with a graticule in magenta and a grid in blue. Note that the graticule has curved meridians while the grid uses straight lines only.