2.測量準備と補正(Preparation & Calibration)


Q. 水路設計(チャンネルデザイン)プログラムでの測線ファイル(*.lnw)の利用(Channel Design Center Line Import)[英語]


The change that was made to Channel Design was not driven by a customer request, but by a desire to provide an easier method of creating a channel file. You can now import a .LNW file, created using the centerline method in the Line Editor, into a Channel Plan file (*.PLN). This allows you to create a line file and clip it to a known channel. You can then quickly modify this into a Channel Plan file that includes template information for volumes calculations. The procedure is outlined below.

  • Create a Line File using the centerline offset pattern in the Line Editor. I chose a BSB chart to provide my channel for this demonstration. The survey lines cover the area. You do need such tight line coverage to create a nice channel.

  • Clip the lines to your channel using a Border file and the Clip Lines feature in the Line Editor.

  • Open the Line file you have just created in the Channel Design program. When the program reads the file, it uses the first line in the file as the centerline of our channel. Once the line is read, it behaves just like a normal plan file.

The start and end points of each line are used to create the left and right toes. Since there are more lines in the file than it requires to create the shape of the channel, the program eliminates points where three or more are in line with each other (using a one foot tolerance). This reduced the original 235 lines created in the Line Editor to 4 left toe points, 3 center line points and 2 right toe points.

Now we have defined the channel using the centerline file, but we do not have a line file with the template data yet.

  • Edit depth, slope and chainage according to your channel. The defaults are:
    • Depth: 20
    • Slope: 3
    • Chainage: 0
  • Create a channel by clicking [Update]. In this example, I have used Smart Corners to fill the gap that we saw at the curve in the original line file. The channel created should have all of the correct settings with template information that can be used to compute volumes and we have coverage on the curve.

  • Check your channel templates using the Profile View to make sure that all of the templates look good and that the channel was created correctly.  
  • Return to the Preview Tab and save your new Line File by clicking [Save] and naming your file.

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