Layer Menu

The Layer Menu contains options for data creation or editing using the selected layers in the Overlay Control Center. Many of these options were previous found in the Overlay Control Center right click context menu.

These functions will apply to selected layers, so it is necessary to select the appropriate layers in the Overlay Control Center first.

Create Workspace File from Selected Layer(s)

This option will generate a workspace just containing the selected layer(s) and their display options. This workspace can later be loaded with the File->Load Workspace menu command.

Export Layer(s) to New File

This option will bring up a dialog to specify the export format. All selected layers in the Overlay Control Center that are compatible with the export format will be included.

Add Selected Layer(s) to Map Catalog

Adds the selected layer to an existing Map Catalog.

Calculate/ Copy Attribute Values

This allow for creation of a new attribute value (or updating of an existing one). This can be calculated by copying the value of some attribute, performing a mathematical operation either between two attributes or between an attribute and some number, or by appending a text string to a value when Simple Calculation is selected.

Selecting Use Formula Calculation option enables the use of additional formulas.

Available Attributes: User may select an attribute to insert into the current formula (use the Insert button to the right)

Available Functions: User may select a function template to insert into the current formula, which includes the function name and dummy parameters where they're expected. Insert the function using the button immediately to the right. Changing the current function in the list displays a function description in the read-only control directly below the function selector. For a full list of available options see Formula Calculator Functions

Enter Formula to Use: An edit control where the user types in the formula that they require.

Insertions from the Available Attributes and Available Functions drop downs determine the current insertion point in this control, and replace any current selection. As changes are made to the formula, a status is updated in the Status control immediately below.

For more information about formulas and available functions see Formula Calculator

Status: Indicates the status of the current formula. If the formula is non-empty, it is evaluated for correctness. If there is no error, then the status will be 'OK'. Otherwise, if there is an error an indication of what the error is displayed. In addition, if there is no error, then the dialog used the current feature in whatever feature collection is being considered to evaluate the value that the formula would compute, as a sample. This is shown below the status.

Use the 'Insert' button to the right of the selected Function to insert a function to use and the 'Insert' button to the right of Available Attributes to add the Attribute name to the string. If the formula is invalid or empty, the 'Calculate' button is disabled. Clicking 'Calculate' will apply the formula to the feature collection.

The dialog below is displayed when you select this option to allow you to set it up:   

Join Attribute Table/ File to Layer

This allows you to join a table of attribute values, either from a DBF file or from a text file, to the attribute table of a selected layer based on a common value of some attribute. You will be prompted to select the attribute from the attribute table file to join against a user-selected attribute from the selected layers. For text files, the first line must contain the attribute/ column names. Whenever a match is found, the other attributes from the data table are added to the matching record(s) in the file.

Split Into Separate Layers Based on Attribute Value

This option allows you to create new layers by splitting the selected layer(s) into new layers based on a particular attribute value or by the description, type, or name of each feature. The new layers will be grouped together using the name of the original layer unless the original layer was already in a group.

Create Layer Coverage Box/ Polygon Area Features

This causes new rectangular or polygonal coverage area features with the same name of the selected overlay (based on display label) to be created for each selected layer. This is useful for creating an image index as the filename of the layer will also be saved as an attribute of the area feature created from it.

Create Area Features from Equal Values

When a single raster or elevation grid layer is selected (with the exception of online sources), this option appears and allows you to create area features covering each distinct color or elevation value encountered in the raster file.

Create Point Features at Elevation Grid Cell Centers

This causes a new layer to be created for each selected elevation grid layer with a spot elevation point feature at each grid cell center location. This provides a handy way to edit elevation layers as you can edit the elevation attribute of the created points or remove bad points, then create a new elevation grid from the layer.

Find Extreme (Min/Max) Elevation Values

This scans the selected elevation grid layers to find the minimum and maximum elevation values and reports both the values and their locations to the user. The complete list (up to 10,000 shared location) will be saved to a file, and a shorter list presented to the user.