Positioning The Cursor In Three Dimension

 Positioning The Cursor In Three-Dimension

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Because the cursors are three-dimensional, placing them correctly can be tricky. For example, if you set the cursors while viewing the cave from above (Plan View), only two dimensions will be visible and so only two dimensions can be set. In other words, you can only see the east and north dimensions because the vertical dimension runs into and out of the screen. This means that the cursors may appear close together, but could in fact be hundreds of feet apart in the vertical direction.


Problems With Two Dimensions. If you only set the cursors in two dimensions, you have to be very careful how you read the measurements. For example, if you have set the cursor from plan view, the vertical aspect of the cursors will be undefined and there could be large vertical discrepancies between the cursors. For this reason, you should ignore the vertical difference, and you should use the two-dimensional length value (2Dlen).


Setting Cursors In Three Dimensions. If you set the cursors in three dimensions, all of the measurement values will be valid. There are two ways to set the cursor in three dimensions. The first is to use the Near Station button. This moves the cursor to the three-dimensional locations of the nearest station.


The second method involves setting the cursors manually. It is useful when you need to make a measurement between locations that are not associated with a survey station. The process requires two steps. First, you set the cursor positions with the program in plan view. This will accurately set the cursor locations for the east and north dimensions. Next, you switch the program to profile view and place the cursors vertically. This will accurately set the cursor locations for the vertical dimension.


Setting Cursors In Profile. You can also set them in three dimensions by putting the program in Profile Mode and then rotating Pitch and Yaw a small amount. You set the cursors, then change rotations. As you rotate, the cursor will appear to shift off target. Keep repositioning until the cursor stays at the right location. The cursor will then be set in three dimensions.


Since the mouse is used to position the measurement cursor on the screen, you cannot zoom or pan using the mouse. However, all the tool bar buttons, menu items and short cut keys still work so you can zoom, pan, rotate and select any normal menu function.