Import terrain contours
Neara offers a number of ways of modelling terrain in a project, including importing terrain contours from a DXF file.
Neara also supports terrain modelling with survey data in .csv files and LiDAR data in .las .laz and .txt files.
Prerequisites and notes:
The units used in a DXF file are assumed to be metric metres
In the DXF file, ensure only modelspace has information
In the DXF file, ensure paperspace sheets are deleted
Remove/purge all unused elements of the drawing, and all unusued layers and blocks
Try to keep the DXF file to import under 50MB
Neara currently supports 3D terrain import from a DXF files containing contour lines. If your terrain data is in another format, such as points, it will not import.
Contour lines should be specified as polylines, with each polyline having a constant z-value (height).
Not all contour lines are 3D polylines. Any that are not will not be converted to 3D terrain when imported.
Only valid contour lines will import. For example, contour lines cannot overlap - any that do will not import or will cause errors.
Ensure terrain layers have valid height data. Some contour layers can have an elevation property of
zerofor all the lines in that layer. These types of layers are not valid and will cause errors when imported with other valid terrain data.Check that your viewable workspace is not empty - the data to import may be outside your current workspace
Check the scale of your DXF: ensure it is
1m to 1 drawing unit
In your project, select Project menu / Import from DXF:
When prompted select a DXF file that contains valid contour lines from your device. A preview will load, including file and geospatial metadata:
Depending on your project's current geospatial reference and the data in the DXF file, you may see a warning about the positioning of the project's design assets and the DXF data. See: Troubleshooting import from DXF files
Under the preview, select the Terrain checkbox.
Neara will try to automatically find the terrain information if no layer is specified. For complex DXF files, it is best to specified the layer(s) the terrain data is contained in. Click in the From Layers input box and select each layer in the DXF that contains contour data to import:
Finally, click the Apply button.
Import terrain as an overlay image
This will render the contents of the DXF contour file to an image, and place the image into the project as a terrain overlay image. This is useful where clearances to existing proposed obstructions, land features property lines need to be met and is shown on a DXF file.
Follow the steps above, selecting the Overlay checkbox instead of the Terrain checkbox:
Click Apply.
If you have the Google Maps or other Map Overlay active, you may not see the overlay terrain contours image.
To view the terrain overlay image, click the Survey tool on the toolbar, and select either of the following options under Map Overlay in the Properties tab:
CAD Import
CAD Import and Google Maps
The Map Overlay will update to display the overlaid terrain image:
If you select the CAD Import and Google Maps May Overlay option, you can control the relative opacity of each overlay:
If you cannot see the terrain at all, check that the Show Terrain option is selected under the View menu:
Import poles
You can further specify the pole layer that the poles sit on, if available in the DXF file, by selecting the Poles checkbox and click in the input boxes to select relevant layers in the DXF for Pole Blocks and Pole Layers:
Google Maps overlay
After importing terrain, if you do not see a Google Maps or similar overlay, you may need to set or update a geo-referenced maps overlay that has a coordinate system assigned to it.
Visualize the terrain
Once a project has terrain data modeled, you can view it in the Perspective, Schematic, and Plan views:
Cancel an import
To close the popup and cancel an unprocessed import, click anywhere outside the popup.