[9 days teach you south Cass 9.1] 08 draw contour lines and process them

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In this lesson, we will learn how to plot and process contour lines.

Course Teaching Plan

Step 1: show the boot file

Step 2: Progress

Step 3: CreateDTMModel

 

Click the contour line menu> Create DTM. In the pop-up "create DTM" dialog box, make the following settings:

√ Single choice "generated by data file", or generated by the drawing high-level point.

√ Single-Choice "display the result of the Triangle network"

√ Check "steep ridge During modeling" and "geographic line during modeling", as shown in.

 

Click OK, and the command line prompts "Please select line: (the ground line should have passed the measurement point. If not selected, press Enter, after you use the mouse to select the geographic line to be considered for modeling, press enter to complete the DTM creation process, and the drawing displays the tin map built by the High-path point. (The ground line is the skeleton line of the landform form and the control line used to describe the landform form. It mainly includes the ridge line, valley line, steep Ridge and slope top bottom line .)

Prompt1:"Generated by data filesThe DTM model automatically generated by the system according to the data file. It is only an entry stage for learning to draw contour lines. And use"Generated by drawing high-level pointsIn this way, you can manually select the height points in the local area of the test area to create a DTM instance. Editing and modifying the Triangle network are the difficulties and advanced stages for learning to draw contour lines.

Prompt2:DTM, which is automatically generated using data files, cannot fully and accurately reflect the changes of the actual terrain in the area, in the future, the drawing worker must edit and modify the automatically generated Triangle network based on the terrain changes in the field, so that the contour lines generated by the DTM model can accurately reflect the actual terrain fluctuations in the measurement area.

Therefore, this tutorial briefly introduces the basic operation process of creating a DTM model and creating contour lines. The deeper operation of this tutorial requires constant practice and accumulation in the actual internal work.

Step 4:You can save the result of modifying the tin or disable the TiN layer.

Click the contour line menu> modify result disk storage. When the command line prompts "disk storage is complete !" The operation is successful.

 Tip:After editing and modifying the automatically generated tin, or directly reading the saved tin file *. when sjw is used to draw contour lines, to make the modified or read TIN Model take effect, you must save the modification results to the disk. Otherwise, the drawn contour lines are not inserted into the modified Triangle network.

 Step 4: draw contour lines

Click contour lines> draw contour lines. In the displayed "draw contour lines" dialog box, set the following parameters:

√ Equal height: 0.5 meters

√ Single choice "cubic B-spline fitting" curve.

Click OK. The DTM model automatically hooks the corresponding contour lines. :

Step 5: Save the tin

Click the contour menu> access to the Triangle network> Write File, and specify the file name and path to be saved in the input Triangle network file name displayed, as shown in.

Click the Save button. When the command line prompts "select the tin to be saved:", select all tin in the drawing area and press enter to save the tin.

Tip:When the drawn contour lines are deleted by mistake, you can use the "Access to the Triangle network"-"Read File" function to read the triangular network file *. sjw, and then draw the contour lines again. At the same time, it is easy to call the saved tin file when the DTM method is used to calculate the earthwork volume later.

 

 Delete a tin

Click "contour lines"> "delete Triangle network" to delete the Triangle network generated when DTM is created.

Click Edit menu> Delete> layer where the entity is located, and click any triangle in the drawing area to delete the sjw layer where the triangle mesh is located.

Contour line note

Note on the elevation of a single curve:

Click the contour menu> contour line note> single elevation note ],

When the command line prompts "select the high (deep) line to be noted:", click the contour line to be noted (rough green solid line) in the drawing area );

When the command line prompts "specify a high (deep) Line adjacent to the legal line:", click the first curve (thin yellow line) with a higher elevation value than the curve in the drawing area ), in this way, the text header of the contour elevation annotation is oriented to the uphill direction.

Notes on batch curve elevation:

First, use the pline multi-line command to draw a multi-line that is orthogonal to the contour line, and the starting point and ending point of the multi-line must be from the elevation to the elevation direction, in this way, the text header of the note is oriented to the uphill direction.

Click contour lines> vertical line elevation ]. When the command line prompts "select (1) only process the curve (2) process all the contour lines <1>", Press enter to note only the curve by default to complete the curve calculation elevation annotation.

Tip:We only need to note the elevation value of 10 multiples of the basic equi-height distance, and note that the elevation header is facing the uphill direction. For example, if the base height of a topographic map with a scale of is 0.5 meters, You need to note that the elevation is a curve of 5-meter integer. In this example, you must note the calculation curve of the elevation value of 495 m and 492.5 m, and the calculation curve of the elevation of 497.5 and M does not need to be noted.

Note on the slope line:

Click "contour lines"> "contour line notes"> "single slope line". When the command line prompts "select the high (deep) line to be noted:", click

The closed contour lines to be noted. When the command line prompts "specify an adjacent high (deep) Line in the direction of the legal line:", click the adjacent contour lines to complete the annotation of the slope line.

As shown in, curve elevation notes and slope line notes.

 

Trim contour lines

Batch trim/Hidden contour lines:

Click contour lines> contour line pruning> batch contour lines. In the displayed "contour line pruning" dialog box, set the following parameters:

√ Trim the contour lines of a Ground Object: Check "buildings" and "Control Point notes ";

√ Trim the contour lines of the annotation Symbol: Single-Choice "blanking"; check "elevation note", "independent symbol", and "text Note ";

√ Processing method: Select "whole graph processing ".

After you click OK, the system automatically trim the contour lines in the entire graph according to the user-specified options. As shown in:

Prompt1: The "hide" option does not actually cut the contour lines. Instead, it only visually hides the contour lines that pass through the ground object and the contour lines that are noted. A single contour line is continuous and complete.

Prompt2: The "cut" option is to cut or interrupt the contour line, that is, trim the trim in CAD or interrupt the break. This operation will increase the points (feature points) on the contour line, as a result, the data volume of the contour lines increases, and the storage capacity of the entire DWG graphic file increases.

Prompt3:We do not recommend that you use the "integral graph processing" method to "trim" the contour lines of "elevation notes", "Control Point notes", and "text notes ", we recommend that you use the "manual selection" method to trim the contour lines. As I have put it into practice, it is easy to "trim" large-area images in the form of "whole graph processing" to see loss of contour lines and intersection of contour lines, in addition, when the "elevation note" is pressed to the "building", the complete building lines may be cut off.

Trim contour linesIf there are several other methods, we will not demonstrate them one by one. You can try it yourself.

 

Remove the contour lines between two lines:

Click "contour lines"> "contour line pruning"> "Remove the contour lines between the specified two lines". When the command line prompts "select the first line, select the lines on one side of a road, river, or trench. When the command line prompts "select the second line", select the lines on the other side of a road, river, or trench, you can trim the contour lines between the second line.

Remove the contour lines in the specified area:

Click "contour lines"> "contour line pruning"> "Remove contour lines in a specified area". The command line prompts "select a closed compound line for contour lines to be removed, you must select a Closed Boundary enclosed by a composite line, such as a pond or house. The system will trim the contour lines in the composite line area. When it is not a closed area, the system cannot complete the trim operation.