The Tool Menu offers the following commands:
The Zoom command selects the zoom tool as the current tool.
To zoom in on a specific point, choose the [Zoom tool] from the toolbar or, [Tool/Zoom] from menu bar. A magnifying glass icon should appear on the screen. To zoom in, left click without dragging the mouse. The view is centered on where the mouse was clicked and will zoom in by a factor of two. To zoom out, right click without dragging the mouse. The view will zoom out by a factor of two, centered on where the mouse was clicked.
Alternately, one can zoom in to a user-defined rectangle by left clicking and then draging a box while holding down the left moust button.
The Recenter command selects the recenter tool as the current tool.
To change the center point of the image without changing the magnification, choose the [Recenter] icon from the Tool Bar. Click on the image to define the new center point.
The Measure command selects the measure tool as the current tool.
To find the distance between along a path on the display or the enclosed area of a set of points, choose the [Measure Tool] icon from the toolbar or select [Tools/Measure] from the menu bar.
You can also save a measurement to a separate feature by right clicking and selecting "Save Measurement" from the list that pops up. You can then export these measurements to new vector files, such as Shapefiles or DXF, or modify them with the Digitizer Tool.
The Pick command selects the pick tool as the current tool. This tool allows you to select vector features (areas, lines, and points) by clicking on or near them. Once selected, a dialog displaying information about the selected item appears.
To pick objects, select the [Pick] icon from the Toolbar or select [Tools/Pick] from the menu bar. Press and release the left mouse button near the objects(s) to be picked. When an object is picked, it will be highlighted and a pick dialog box will be displayed. Right clicking the mouse button cycles through each of the elements located near the selection point, displaying the information in the dialog box.
The type of information dialog that appears for a given feature will depend on the of data file that it came from. For example, the information dialog that appears for a SDTS line feature is shown below.
The PathProfile/LOS command selects the 3D path profile/LOS (line of sight) tool as the current tool. This tool allows you to get a vertical profile along a user-specified path using loaded elevation datasets. In addition, registered users can perform line of sight calculations along the defined path.
To define the path along which to generate the 3D path profile, first select the path profile tool as your current tool. Press and release the left mouse button at the position where you wish to start the path. Move the mouse to the next position that you want to include in the path profile, then press the left mouse button again. Right click on the last location in the path profile to complete selecting points and display the Path Profile/Line of Sight dialog (pictured below). The Path Profile/Line of Sight dialog will appear displaying the 3D path profile of the selected path. Any points along the path that did not have elevation data underneath will be treated as an elevation of zero.
You can also generate 3D path profiles for existing line features by selecting the line feature in the Digitizer Tool, right clicking, then selecting the Generate Path Profile From Line option on the menu that is displayed.
The Path Profile/Line of Sight dialog displays the 3D path profile and provides several options related to the profile. A vertical scale is displayed on the left hand side of the profile window. The start and end coordinates of the path are displayed at the top of the profile window. If more than two points are in the path, the intermediate points will be marked in the profile window with a yellow dot. These intermediate points can be toggled on and off using an option available by right clicking on the path profile window. Also note that this dialog is resizable.
Right clicking on the profile window brings up an options menu allowing the user to change the start and end positions and to select the units (meters or feet) to display the elevations in.
The File menu contains options allowing you to save the path profile/line of sight data to a file. The individual options are described below.
The Save To Bitmap... options allows registered users to save the contents of the path profile window to a Windows bitmap (BMP) file for use in other applications.
The Save Distance/Elevation... option allows registered users to save all of the distances and elevations along the path profile to a text file. Each line in the text file will be formatted as follow:
The Save To XYZ... option allows registered users to save all of the positions and elevations along the path profile to a text file. Each line in the text file will be formatted as follow:
Pressing the Line of Sight... button brings up the Setup Line of Sight/Earth Curvature dialog (pictured below), which allows the user to configure a line of sight calculation along the selected path. You can only perform a line of sight analysis if exactly two points are in the path profile (e.g. line of sight analysis cannot be performed on multi-segment paths).
The From Sight Elevation section allows the user to select the height at the start position (left side of graph) to use in the line of sight calculations. This height can be specified in either feet or meters above the ground or above sea level. The To Sight Elevation section provides the same functionality for the end position (right side of graph).
The Earth Curvature section allows the user to specify whether they want to take the curvature of the earth into account while performing the line of sight calculation. In addition, when earth curvature is being used, they can specify an atmospheric correction value to be used. The atmospheric correction value is useful when determining the line of sight for transmitting waves whose path is affected by the atmosphere. For example, when modeling microwave transmissions a value of 1.333 is typically used to emulate how microwaves are refracted by the atmosphere.
Selecting the Exclude Endpoints when Finding Minimum Clearance options causes the first and last 5% of the elevations along the profile to be ignored when finding the minimum clearance point.
After setting up the line of sight calculation in the dialog and pressing the OK button, the line of sight will be displayed in the path profile window (pictured below). Along with the line depicted the actual line of sight, the position and vertical separation of the minimum clearance of the line of sight will be displayed with a dashed red line in the path profile window.
The View Shed command selects the view shed analysis tool as the current tool. This tool allows registered users to perform a view shed analysis using loaded elevation grid data with a user-specified transmitter location, height, and radius. All areas within the selected radius that have a clear line of sight to the transmitter are colored with a user-specified color.
To perform a view shed analysis, first select the view shed tool as your current tool. Press and release the left mouse button at the position where you wish to place the transmitter. At this point, the View Shed Setup dialog (pictured below) will appear, allowing you to setup the view shed calculation.
The View Shed Setup dialog provides options that allow the user to precisely setup the view shed analysis that they wish to perform.
The Description provides the user with a place to enter a name to identify this view shed analysis. This name will be displayed in the Overlay Control Center and will also be the name of the transmitter point created by the analysis for display on the map.
The Transmitter Elevation section allows the user to specify the height of the transmitter that the view shed analysis will be simulating.
The Receiver Elevation section allows the user to specify the minimum height above the ground or sea level from which the transmitter must be visible for the point to be considered visible. Most of the time you'll want to specify an elevation above ground, but specifying an elevation above sea level can be useful for aviation purposes.
Optionally, you can also specify that the receiver elevation should be calculated based on an elevation angle relative to the horizon from the transmitter. This is useful if you have something like a radar dish that points up at some angle and you want to see where the signal can be seen.
The View Radius section allows the user to specify how far in each direction from the transmitter to check for visibility. Typically you'd want to set this to the effective range of your transmitter.
The View Angle section allows the user to limit the view shed to a particular subsection of the complete radial area. The Start Angle specifies the cartographic angle at which the radial subregion begins. This angle is a cartographic angle, meaning that 0 degrees is north and angles increase clockwise. The Swept Angle specifies the number of degrees clockwise to include in the view shed. For example, if the transmitter being analyzed sweeps an arc from due south to due west, a start angle of 180 with a swept angle of 90 would be used. To perform a view shed analysis over the entire area, keep the defaults of starting at 0 degrees and sweeping through 360 degrees.
The Earth Curvature section allows the user to specify whether they want to take the curvature of the earth into account while performing the view shed analysis. In addition, when earth curvature is being used, they can specify an atmospheric correction value to be used. The atmospheric correction value is useful when determining the view shed for transmitting waves whose path is affected by the atmosphere. For example, when modeling microwave transmissions a value of 1.333 is typically used to emulate how microwaves are refracted by the atmosphere.
The Sample Spacing section allows the user to specify the spacing of elevation samples when calculating the view shed. The sample spacing controls the interval at which elevation samples are examined to determine visibility. Smaller values result in more accurate, but more slowly generated, view sheds.
Pressing the Select Transmitter Location... button displays a dialog that allows the user to adjust the exact transmitter coordinates from the coordinates where they clicked.
Pressing the Select Display Color... button displays a dialog that allows the user to select the color in which to display the visible areas on the map.
After setting up the view shed calculation in the dialog and pressing the OK button, the view shed analysis will be performed and when complete, the results will be displayed on the main map display as a new overlay. All visible areas within the specified radius will be displayed using the selected color. The overlay will default to being 50% translucent, allowing you to see areas underneath the view shed. You can modify the translucency of the overlay in the Overlay Control Center.
In addition, a small radio tower point will be created at the selected transmitter location. When selected using the pick tool, this point displays information about the view shed analysis as shown below.
Selecting the Control Center... menu item or toolbar button displays the Overlay Control Center dialog. This dialog is the central control center for obtaining information and setting options for all loaded overlays. See the Overlay Control Center section for complete details.
Selected the Configure... menu item or toolbar button displays the Configuration dialog. This dialog provides for general setup of Global Mapper display options. See the Configuration section for complete details.