“Long Path” Warning in HDPath™
Q: Why do I keep getting the message “Are you sure you want to draw this long path?”
A: The HDPath function in TAP includes a warning to avoid inadvertently drawing excessively long path profiles.
With TAP6.0.2213 or later and a Maintenance Subscription date of February 29, 2008, or later, you have some additional control over this message.
Note that all values in this example are for demonstration purposes only. You should determine appropriate settings for your application.
The TAP Fixed Facility database can contain existing or proposed sites over any geographical area. The “Long Path” warning is intended to protect you from drawing unrealistically long profiles.
For example, suppose you have sites in your Fixed Facility database for both Colorado and Mexico. If you select sites that are thousands of kilometers apart, you probably do not intend to draw the path.
For example, if you were working previously with a path between two sites in Mexico, and now you want to draw a path in Colorado, when you select the Colorado Transmitter site, with the Receiver site is still set to a location in Mexico, you could encounter the following scenario in HDPath:
If you have the topographic data for the entire area, and you actually do want to draw the path, you can click the “Yes” button. It may take several minutes, and the effect of earth curvature over the long path will be extreme, but you should be able to draw the path.
However, if you actually are just changing sites to draw a new path in Colorado, the “Long Path” warning gives you the opportunity to avoid needlessly attempting to draw the profile. You can click the “No” button, then select the desired Colorado location for the Receiver facility, and draw the profile you actually want to see.
The “Long Path” warning is especially important if you have checked the AutoDraw Path option in the HDPath Configuration menu:
This option causes the program to immediately redraw the profile anytime a change is made. Selecting a Colorado transmit site while the receive site is in Mexico, with the AutoDraw option enabled would result in an automatic attempt to draw the long path. The “Long Path” warning prevents this unintended operation.
The “Long Path” warning message is actually triggered by a combination of the length of the path between the selected sites, and the topo data step value. For example, a path length of over 2500km and an increment value of .01km between elevation points would result in over 250,000 elevation points.
The default threshold value is 1000 points, as found in the HDPath Configuration menu:
However, there may be cases where even paths you actually want to draw exceed that number of points. For example, any path over 100km long with a data increment of 0.1km will generate the warning:
If you typically draw paths that exceed the default setting, you can increase the limit. In the HDPath Configuration menu, click the “1000 Point Warning” item:
An input box will be displayed. Enter the limit for the number of points you want to use to trigger the “Long Path” warning message:
Click the OK button to use that number in the future.
The new value will be displayed in the Configuration menu, and you will be able to draw the longer paths without the warning message and without the yellow background for the path information above the profile graphic.
With TAP6.0.2213 or later and a Maintenance Subscription date of February 29, 2008, or later, you have some additional control over this “Long Path” warning message. If you are making numerous changes to examine different possibilities for a “long” path, you can avoid having the message display repeatedly, even if the number of points exceed the warning limit set in the Configuration menu.
In the HDPath Configuration menu, the item “No Warning for Same Path” enables you to suppress the message if you are drawing the same path, and changing only items such as antenna heights that do not affect the number of points along the path.
To select this option if it is not checked, click it to select it. (You can click the checked item to un-check it.)
With the “No Warning for Same Path” option checked, the “Long Path” warning message will only be displayed the first time you draw a path during a session of HDPath. Changes to the profile which do not affect the number of elevation points (such as changing the earth curvature or antenna heights) will enable you to redraw the path without the warning message.
However, if you change the coordinates of either end point, or the topo data step value, the warning will be displayed again the first time you draw the new profile.
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Copyright 2008 by SoftWright LLC
