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The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals - Leaving Cert DCG - Question C-1 - 2021
Question C-1
The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals. (a) On the map supplied, draw a vertical sectio... show full transcript
Worked Solution & Example Answer:The accompanying map, located on the back page of Section A, shows ground contours at five metre vertical intervals - Leaving Cert DCG - Question C-1 - 2021
Step 1
Draw a vertical section (profile) on the line AB
Answer
To draw the vertical section on line AB:
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Measure Heights: Use the contour lines on the provided map to identify the heights at various points along line AB. These points might fall between contour lines, and interpolation may be necessary.
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Draw Horizontal Lines: From the measured heights, draw horizontal lines corresponding to each point along AB in the vertical section.
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Project points: Project the heights from AB vertically to the contour map and determine the intersection points with contour lines.
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Complete the Section: Connect these points to illustrate the geological profile along line AB.
Step 2
Plan of triangle CDE
Answer
To draw the plan of triangle CDE:
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Identify Points: Using the map, locate points C, D, and E based on their contours.
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Construct the Triangle: Plot these points on a coordinate system to create triangle CDE.
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Label Appropriately: Ensure to label each point clearly with its respective elevation based on the contour information.
Step 3
Elevation of triangle CDE
Answer
To create the elevation of triangle CDE:
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Determine Elevations: Find the elevations of points C, D, and E using the contour map.
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Draw the Triangle: Sketch the triangle on a vertical plane, indicating the elevations at each vertex. Ensure to include the ground level for reference.
Step 4
Determine the strike and dip of the stratum
Answer
To find the strike and dip:
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Horizontal Line in Elevation: Draw a horizontal line from the highest point of triangle CDE (this represents the strike).
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Strike in Plan: Project the direction of the strike onto the plan view, ensuring to align with the contours.
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Determine Dip Projection: Measure the angle at which the stratum descends from the horizontal line.
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View Direction for Dip: Establish the direction in which the dip is observed. This may represent the angle between the horizontal line and the actual stratum line in elevation.
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Calculate Dip: Finally, compute the dip using the formula: ext{Dip} = an^{-1}igg( rac{ ext{Vertical drop}}{ ext{Horizontal distance}}igg), where you will need to use two heights from the edges of the triangle CDE.