Thursday, 24 November 2011

Creating Surfaces from LINZ NZTopo50 maps

In rural New Zealand there is generally a lack of Lidar information to build 3d surfaces within Civil3d. However Land Information New Zealand (LINZ) have made available on their website shp file versions of their NZTopo50 series maps that contains contour information at 20m intervals. You can use these contours to create surfaces and define catchments automatically in Civil3d.

To build a surface is Civil3d:-
1. Goto the LINZ website and choose a map of your area of interest
at the bottom of the particular map you will see the shp file download option. Download and unzip the shp files.

2.  Now you have to import the shp data into a new drawing using MAP and assign the object data elevation to the Z value of the polylines that represent the contour lines. There are a couple of tutorials on the web how to do this already here and here.
Note the shp files downloaded are in NZTM co-ordinate system so you may have to do a co-ordinate transformation on import as well.

3. Now that you have the contours with the correct elevation you can build a surface in Civil 3d in the normal way and define catchments and flow paths using the built in Civil3d’s tools.

No comments:

Post a Comment

Related Posts Plugin for WordPress, Blogger...