Color Shaded Relief Models – Cap Pele, New Brunswick

Color Shaded Relief Models of Cap Pele, New Brunswick Color Shaded Relief Models of Cap Pele, New Brunswick

The two images above represent artificial three dimensional perspective views perspective views from different points of origin featuring color shaded relief models that were created from high resolution LIDAR digital surface models as part of a LIDAR flood modeling graduate research project.

The study area for the project consisted of the coastal Gulf Shore region of southeastern New Brunswick from Kouchibouguac National Park south to Jourimain Island (location of the Confederation Bridge). The coastal zone of New Brunswick is a picturesque fishing region that boasts several kilometers of sandy beaches with some of the warmest salt water temperatures north of Virginia.

LIDAR surface modeling of Bouctouche New Brunswick

Color Shaded Relief (CSR) image generated from Bald Earth LIDAR points on the left, Middle image is of a Digital Surface Model generated with “All the LIDAR points” and on the right is an air photo for the same area. The area shown in the data samples are of Bouctouche in New Brunswick at a scale of 1:6000. Data sets were part of my gradute research work at the AGRG / COGS in 2003.

LIDAR surface modeling of Bouctouche New Brunswick

Digital Terrain Modeling – Shaded Relief Models

A shaded relief model uses different color shades according to the varying levels of elevation and azimuth to create an enhanced simulated terrain. The shading is done with the assumption of a defined light source at a fixed location, shone across the surface. The user-specified light source will then determine the positions of shadows and highlighted slopes making ones facing light source appear bright and those facing away appear dark. By default shaded relief models are created with a grey scale ramp that represent the surface reflectance from the light source at any altitude and any azimuth however adding color to it can add an extra chromo stereoscopic component to it.Shaded Relief Model of Lismore, Nova Scotia
Assuming that a straight line is drawn connecting the user defined point source to the top left pixel of the image, the azimuth angle is the aspect of this line in degrees clockwise from north; the elevation angle is the elevation of the line in degrees from the horizontal.

The shaded grey level for each cell is the result of a calculation from the cosine of the angle between the normal vector to the surface (i.e. slope andaspect) and the direction of illumination. All surfaces not illuminated by the light source such as a slope of 90 degrees will be set to 0. An elevation exaggeration is sometimes added to help enhance the features of a fairly homogeneous surface.

In the example shown to the right, a raster aspect map of Lismore, Nova Scotia was derived from a digital elevation model (DEM) calculated with an azimuth angle of 315 degrees and an elevation angle of 45 degrees.

Shaded Relief related:

 

Terrain Analysis of the Antigonish Highlands

Integration of Digital elevation Models (DEMs) and Imagery to provide Terrain Analysis of the Antigonish Highlands using DEMs generated from RADARSAT Satellite data