Using Downloadable Contours from Kespry Cloud

Owned by Patrick Dowd
Aug 08, 2022
2 min read

Contours are one of the most popular data downloads from Kespry Cloud, and they can easily be used in any system that can read shapefiles.

The contours download is packaged as a zip file containing a number of shapefiles.  These are:

  • Contours - Feet, which includes contours for the shapefile at a 1 ft interval

  • Contours - Meters, wihch includes contours for the shapefile at a 1 m interval

Each contours package consists of SHP, DBF, PRJ, and SHX files.

 Contour Coordinate Systems

The coordinate system that your contours are exported in will be the same as all other data exports.  By default, exports are in WGS84 coordinates; to customize this, please reach out to Technical Support. Note that the contour interval (feet or meters) is independent of the coordinate system - if you are using a coordinate system in meters (e.g. a UTM grid) you will still receive contours in both feet and meters, and can choose to import either.  

Vertical Datum

For flights done by the original Kespry Drone or the Kespry Drone 2, the contours will be labelled in the NAVD88 vertical datum.  This is the most commonly used vertical datum in North America, and is widely used across construction, mining, and surveying.  GPS natively uses the WGS84 vertical datum, which can vary significantly at some points.  If your contours are not at the altitudes you expect, your "known" elevations are likely in WGS84.  For a deep dive into vertical datums, check out the United States Geological Survey guide here.

Contour Resolution

Smoothed contours provided by the Kespry Cloud are intended for general orientation and large-scale use. Because the smoothing process removes some detail, we recommend using 3D Mesh or Point Cloud exports for technical engineering work to ensure maximum resolution.

Unsmoothed contours are more accurate but we still recommend using a 3D Mesh or Point Cloud file. At very small scales you would be able to see the "staircase" zig-zag of the contours that have been generated from a raster file.

 Scaling Issues on Import?

If you're importing contours into CAD software and they appear to be scaled incorrectly, check that the units of the project you are importing into match the coordinate system the contours were exported in.  (For example, if the CAD project is in meters, confirm that the coordinate system of the export is also in meters.)  If the units don't match, most programs allow you to reproject the contours into your chosen units.

Remember that this coordinate system/unit matching is different than the contour interval.  The contour-meters and contour-feet files from Kespry Cloud have different intervals, but are in the same underlying coordinate system and units.