Remote Sensed Image

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3 Band digital remote sensed image which will be use as a basemap and digitise data layers. Also set the geographical projection for the project.

Digitising and Populating Geodatabase

I am producing a 3D polygon layer which will represent neighboring farms. I have marked the steps to be taken before extropolating 3D data from the layer. The 3D polygons will be used to produce a 3D model of the area.

Digitising Polygons from Remote Sensed Image

The factory is digitised and represented by a polygon layer. The table is populated with attribute data which can be used in an analysis.

Analysing Buildings Attributes

Attribute data were used to extruded the buildings according to the amount of work force present. Its clear which buildings has the highest work force.

Digitising Roads

The remote sensed images proves a vital source in GIS as prooven in this excample. I have digitised roads, constructing a road layer presented by vector lines.

Extract Elevation

I have extracted elevation data from the TIN to create an elevation layer. This particular elevation layer was used to produce a 3D model of the entire project.

Elevation Raster

For accuracy purposes I have altered the colour of the layer to match the aerial photograph as close as possible. If the rivers or mountains doesn't correlate to the photographs entities then I will know an error occurred somewhere in my conversion processes.

Establishing Contours

Using the elevation attributes made it possible to create contour lines as I have illustrated on the following process.

Hillshade - 3D Effect

I constructed a "hill shading" image which makes the image appear in 3D although it's still 2 dimensional. The shading and lighting effects on the image allows the user to visualise the terrain more accurately.

Compare Remote Sensed Images

Combining layers gives you a interesting perspective. By comparing the reproduced layers to the aerial photograph its possible to establish if your contours lines up or even if the river path lines up. Its one method of establishing data accuracy.
The elevation layer reveals a yellow flat potentially flood zone surrounded by 3 major outcrops/mountainous regions represented by a grayish colour.

Conclusion
Remote sensed images forms the foundation of a GIS, entities such as roads, vegetation, buildings can be extracted from these images and be analysed on an individual basis. The elevation layer adds a third dimension to your data which enables you to analyse entities affected by elevation such as water flow, vegetation growth, oil-spills even population distribution and development.

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