Line of Sight
The Line of Sight section consists of the following.
Profile Window
Displays the profile graph along a line of sight selected on the input raster, as shown below:
| Item | Name |
|---|---|
| 1 | Graph Window - Line of sight is plotted on the graph window. |
| 2 | Data Table - The data that is calculated for the line drawn on the map. |
| 3 | Profile List - A profile is created for each line drawn on the map. |
| 4 | Visual Indicator - Displays the message for the selected profile. |
- Select Tools - Click tool to pick buttons for selecting, zoom in, zoom out, pan and selection of graph.
- Fit to Window - Click this to fit the chart to the window.
- Lock Profiles - Click this to lock the selected profile. When locked, the profile will not be updated when the corresponding line is changed on the map window.
Visual Indicator
A profile is generated on the Graph window for each line of sight drawn on the map. You can select the desired profile from the Profile list. When you select a profile from the list, a message is displayed to alert or inform you about the profile. For a valid line of sight, the source point and the destination point must fall in the valid cell.
| Message | Explanation |
|---|---|
| Source origin not over a valid cell, so height can not be determined. | This error appears, if the source viewpoint falls in an invalid cell. |
| Destination origin not over a valid cell, so height can not be determined. | This error appears, if either the source or destination viewpoint falls in an invalid cell, the visual indicator shows "End point is not visible". |
| End point is not visible. | This information displays, if either the source or destination viewpoint falls in an invalid cell. |
| End point is visible. | This information displays, if the destination viewpoint falls in a valid cell. |
Axis Properties
The Axis Properties option gives you control on how you want to plot your data on the graph window. It does not change your data, you are only plotting the data in a better way. Specify a Min/Max value for X-axis and Y-axis to change the range of data to be plotted and make a better chart.
X-Axis - to control the display of the base line or X-axis of the profile. Specify the range of the X-axis (Min and Max values) and click on the graph window, the chart gets updated.
Y-Axis - to control the display of the Y-axis of the profile. Specify the range of the Y-axis (Min and Max values) and click on the graph window, the chart gets updated.
Spacing - You can specify the spacing for better analysis of your data.
You can also plot negative offset value.
Export
Click 
on the upper-right corner in the Line of Sight dialog to save the Line of Sight profile as an image (jpeg, bmp, png, tif, or gif).
Options
Click 
on the upper-right corner in the Line of Sight dialog to access the various options to configure the Line of Sight.
This window contains:
- Profile Options
Specify Sample Count - A point is created where the Line of Sight intersects the raster cells. You can control the number of points to be displayed on the Line of Sight profile by specifying the sample count. When you select Specify Sample Count check-box, the Maximum Sample Count box appears and displays the default number. The default number that system displays is the maximum number of points created by the Line of Sight. You can modify this value and enter a less number of points for analyzing the Line of Sight on the profile window.
Note: The number you enter must be less than the default number. If you specify a higher number of points than the default number, points will only be created up to the default number.- Point Marker - Denotes the marker on each point on the profile. The options are Crosshair and Popup Marker showing the distance and value of each point on mouse hover on the profile window.
- Show Point Symbol on Map - Denotes the point marker symbol on the map window along the profile. Select this checkbox to enable and select the symbol, color and size.
- Profile Thickness - Denotes the thickness of the graph on the profile window.
- Chart Title - The title of the profile chart.
- Axis Options
- X-Axis Unit of Measure - Denotes the distance unit on the X-axis. The value at each point shows the distance from the source.
- Show X-Axis Label - Denotes whether the label along the X-axis needs to be displayed on the graph.
- Show Y-Axis Label - Denotes whether the label along the Y-axis needs to be displayed on the graph.
- Show Zero Value Line - Denotes whether a straight line from origin (0,0) needs to be displayed on the graph.
- Aspect Ratio[X:Y] - Denotes aspect ratio of X-axis and Y-axis. By default, it is set to Automatic, clear the check-box to override it.
- Show Horizontal Grid Lines - Denotes whether horizontal grid lines need to be displayed on the graph.
- Show Vertical Grid Lines - Denotes whether vertical grid lines need to be displayed on the graph.
- Background Color - Denotes the background color of the graph.
- Major Grid Lines Color - Denotes the color of the major grid lines of the graph.
- Minor Grid Lines Color - Denotes the color of the minor grid lines of the graph.
- Line of Sight Options
- Source Viewpoint X - Denotes X Coordinate for the observer/source.
- Source Viewpoint Y - Denotes Y Coordinate for the observer/source.
- Source Viewpoint Offset - Denotes the height of the observer/source above terrain.
- Destination Viewpoint X - Denotes X Coordinate for the destination.
- Destination Viewpoint Y - Denotes Y Coordinate for the destination.
- Destination Viewpoint Offset - Denotes the height of the destination.
- Parameter Units - Denotes Offset unit for source and destination viewpoint.
- Raster Vertical Units - Denotes the vertical unit of raster's cell value. By default, the vertical unit information is derived from the band information for the selected band in the input raster. However, you can override it by selecting the required unit from the drop-down list.
- Earth Curvature Model - Denotes the earth curvature correction model.
- Plan - Select this if you want to draw the visible and invisible segments in the path of line of sight on the map.
Export...
Click Export... to export the Line of Sight profile details as a MapInfo TAB or CSV.