Monthly Archive: November 2014

Satellite Image Interpretation for Land Cover Classification

SBL’s Geospatial wing recently won a project from Canada for the delineation of Land cover in Northwest Territory. This is again a reaffirmation of the varied skills of the Geospatial team wherein our pool of experts were able to provide a better solution to the forest department based on our quality of interpretation of the sample data and competitive pricing.

Land cover basically refers to the interpretation of land features that are visible on the surface of the earth. It does not cover the land usage which comes under Land use. 

Land cover classification includes land features like trees, water bodies, bare earth and rock outcrops. In the present study our task was to interpret Land cover in forested regions of Northwest Territories, Canada. The input image provided by the client was mono satellite image and each image covered an area of 4

SBL’s experienced interpreters delineated the treed and non treed areas and created polygons out of it. The client had specified a minimum area for forest polygons and the area specified was 4 hectare and for non forested area polygon it was 0.5 hectare. The classification was done based on the tone and texture of the features(Fig.1).

Forest delineation based on tone and texture

The tree heights, texture and tree density were taken into account for the delineation. Trees situated in the high land regions will have a different tone, texture, height and density with respect to the trees in the high land and mid land regions(Fig.2, Fig.3).

Landcover classification in highland region

Landcover classification based on density of vegetation

Various tree species occurring in the forest areas display unique textural and tonal characteristics which were used as guide for the interpretation.

The water bodies consisted of rivers, major streams and also the closed water bodies like lakes which fall within the area stipulation of 0.5 hectares were also captured (Fig.4).

Flood plain delineation

Rivers were captured at the edge of water and flood plains were delineated wherever the width is greater than 20m. The digitization was to be done in a scale level of 1:2000 and 1:2500 and the final output was viewed in a scale of 1:10000 in order to find out any dangle polygons, large polygon and also to merge adjacent polygons if necessary. The entire digitization was carried out in ArcGIS environment and the final output was delivered as shape files to the client.