Import terrain mesh from Google Earth

Toolbar:

Menu: CAD-Earth > Mesh commands > Import terrain mesh from Google Earth

Command line: CE_IMPGEMESH

CAD-Earth version: Plus.

Command description:

A terrain mesh can be created inside an existing closed polyline or along a polyline path calculating point elevations from Google Earth using this command. By specifying the origin point, rotation angle and distance between rows and columns the mesh density and precision can be adjusted. The resulting mesh can be processed to obtain contour lines, dynamic profile and section drawings complete with annotations.

Terrain mesh obtained from Google Earth (isometric view)

Dialog box settings (Mesh tab):

Get terrain mesh from Google Earth (Mesh tab)

ØMesh generation.

·Create mesh grid inside a closed polygon. An existing closed polyline must be selected to create the mesh. Distance between rows and columns, rotation and mesh origin point must be specified.

·Create mesh grid along a path. An existing open polyline must be selected. The distance between stations, offset to the right and left and the distance between sample points, must be provided.

ØMesh inside a closed polygon.

·Distance between rows. Specify width for each grid tile.

·Distance between columns. Specify a height for each grid tile.

·Rotation. You can type a numeric value or select the angle selection button to pick two points in the drawing.

·Mesh origin point. Type a value to displace the mesh in the X and Y direction. You can also press the point selection button to pick a point in the drawing.

ØMesh along a path.

·Distance between stations. Specify the interval distance along the polyline where the points to the right and left will be calculated.

·Distance between points. Specify the interval distance between points to the right and left to be calculated in each station.

·Distance to the right. Specify the total distance where the points to the right will be calculated.

·Distance to the left. Specify the total distance where the points to the left will be calculated.

ØSelect polyline button. Press to pick the polyline where the mesh will be placed.

Dialog box settings (Settings tab):

Get terrain mesh from Google Earth (Settings tab)

ØMesh color.

·User layer color. Mesh triangles will be created using the current layer color.

·Use defined color. Mesh triangles will be created using a color chosen by the user.

ØCurve smoothness. If the closed polyline has curved sides they will be converted to straight segments before the polygon representing the polygon outline is added to Google Earth. The number of resulting segments will be proportional to the maximum segment length and the maximum deflection angle between consecutive segments.

ØShow place in Google Earth. After the mesh triangles are created, Google Earth will automatically be activated and zoomed to the place where the mesh is physically located. A folder will be added to Google Earth's temporary places containing the polygon representing the mesh outline.

ØShow mesh lines in Google Earth. Routes will be added to the mesh folder in Google Earth's temporary places for each horizontal and vertical mesh grid line processed.

ØElevation offset. Entered value will be added to the calculated elevations to displace the grid vertically. A positive value moves the grid up and a negative value moves the grid down.

Tips:

·Before using this command the current drawing must be georeferenced to establish the conversion parameters between the drawing and the latitude/longitude coordinates of the corresponding site.

·The terrain configuration in Google Earth is not as accurate as the configuration obtained by a site survey. The resulting mesh is not recommended for projects where high accuracy is required.

·You can use the 'Show georeferenced drawing objects' command to be sure the drawing is correctly georeferenced before using this command .