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Lesson  1

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This tutorial covers how to convert the 2D polylines to 3D polylines assigning "Z" values to them and displaying the "Z" values by using GeoTools Polyline Toolset and Annotation commands.

1. Open the drawing named lesson1.dwg which is located in your GeoTools Tutorials folder. This folder is located in the folder where you have installed GeoTools.

2. You should see a drawing (see Image 4-1) of a pipeline layout, represented by set of 2D-polylines. Make Save As of this drawing in any of your desired folder.

Image 4-1

3. First we will convert the 2D-polylines to 3D-polylines, 

Converting 2D-Pline to 3D Pline

1.Click on the menu GeoTools => Polyline Tools => Change ->2d->3d->2d => 2D-to-3D. or type GT_CH2D3D at the command prompt.    

Image 4-2

2. This will pop-up the GeoTools Standard selection dialog box as shown below in (Image 4-3)

Image 4-3

3. Then from the standard selection dialog box (shown above in Image 4-3) you can select the objects in various ways i.e. 

a) You can click on the button Scan entire drawing. this will scan the entire drawing for selecting the 2D-polylines. 

b) Or you can use Scan selected objects for selecting the required objects and while selecting you can also use the Properties of object to select. for example we will select all the 2D-Polylines
    which are drawn on layer PIPE 

4. So for selecting the polylines drawn on layer Pipe under Current Selection Values  in option Layers type Pipe*  and with crossing polygon select the polylines. In this way it will ensure that only
    polylines from "Pipe" layer are selected. 

5. Lastly click on the button Apply to convert the selected 2D-polylines to 3D-polylines.     


After performing the above steps the 2D-polylines are converted to 3D-polylines with Zero "Z" elevation, so our next process will be to add the "Z" elevation to the 3D-polyline.

Adding the "Z" elevation to the 3D-polyline.

1. Click on the menu, GeoTools => Polyline Tools => Create / Edit Express Pedit. or type GT_XV at the command prompt.

Image 4-7

2. Select the 4th polyline from the top as shown in the above (Image 4-7) and then => type "Z" at the command prompt to add the Z elevation to the vertex. And to move around the vertex type "N" or  "P", and add the following "Z" values, for the selected polyline at the specified vertices.
i) 292.0 ii) 294.5 iv) 300.0 vi) 305 ix) 312.6 xii) 316.5 xiv) 320.0

3. Repeat the step number 2. for all the polylines.


After performing the above steps "Z" elevation, is assigned to the 3D-polylines at specified vertices (known elevation loactions). But in between vertices still 
have "Zero" elevation. We will now populate all the in-between vertices using linear interpolation method 

Ensuring non zero "Z" elevation to all the vertices

1. Click on the menu, GeoTools=> Polyline Tools Assign Interpolated Z values. or type GT_Pl_Inter at the command prompt, you will get a dialog box as shown below. (Image 4-5)

Image 4-5

2. You can type required Zero tolerance value in the Zero tolerance box. 

3. To generate output file of interpolation  check the box "Create interpolation output file" and specify the location of output file by clicking on the button "Output filename", then click on OK

4. After clicking on OK button Standard selection dialog box will appear as shown above in (Image 4-3), to select all polylines click on "Scan entire drawing" button. 

5. Finally click on Apply button this will fill in all the zero [0.0] elevation vertices with non-zero values based on a linear distance interpolation between the next non-zero vertex elevation found.


Labeling the "Z" values at each vertex

1. Click on the menu, GeoTools=> Annotation => Label Polyline Vertices or type GT_Vxlabel at the command prompt, you will get a dialog box as shown below. (Image 4-4)

Image 4-4

2. Do the following settings in vertex labelling dialog box 

a) Under Annotate using choose the  option "Z (Vertex Elevation)"

b) Under Prefix Options choose Prefix with X=, Y=, Z=, specify value "1" in text boxes of Horizontal and Vertical text offset from the vertex.  

c) Specify the required text height, rotation angle in the respective boxes

d) Click on the Select button to specify the layer for vertex labeling. The layer you select will be shown in the Label layer box

e) Once all the options are set click on OK button

3. Then the standard selection dialog box will appear, click on Scan Selected Objects button to select the polylines you want to label the "Z" co-ordinates. 

4. Finally click on Apply button to label the selected polylines with "Z" co-ordinates as shown below in the (Image 4-6).   

Image 4-6

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