Monoplotting, Steps Involved, Steps Involved, Applications of Monoplotting

Monoplotting

It is a photogrammetric technique that uses a single aerial image along with a Digital Elevation Model (DEM) for extracting 3-D spatial information.

It is a real time correction procedure and doesn՚t yield a new image which means no resampling is carried out.

It is based on the principle that the position of a point in a 2-D image could be determined by its location on the DEM.

This approach of monoplotting is possible by using a hardcopy image on a digitizer tablet, or by on-screen digitizing on a computer monitor.

It is simple and a cost-effective technique that could be used for generating 3-D models of objects and landscapes.

It is based on the reconstruction of the camera՚s position now of image exposure w. r. t the GCPs, i.e.. , the terrain.

Where stereoscopic images are unavailable, this is extremely useful, for example while working with historical aerial photographs or satellite images.

Information related to the terrain relief is supplied by a DTM of adequate accuracy.

The DTM needs to be given in the required map projection system along with the elevations to be expressed in an adequate vertical reference system.

The computer uses the DTM for calculating the relief displacement for every point and corrects it as shown in Figure

Steps Involved in Monoplotting

Acquiring a DEM

Use of DEM for providing the vertical reference for the image.

The DEM can be derived from different sources such as LiDAR data, stereoscopic images, or a combination of both.

Selecting a Ground Control Point

A GCP is that point on the ground that has been already surveyed and has known coordinates.

The GCP is used for calibrating the image and the DEM.

Digitizing the Image

For identifying the features of interest.

The digitized features are used for calculating the 3-D coordinates.

Generating the 3-D Model

Generation of a 3-D model by triangulating the digitized features.

Applications of Monoplotting

3-D Mapping

Use of monoplotting for generating 3-D maps of objects and landscapes.

The maps could be used for a variety of purposes like planning, disaster response, and environmental monitoring.

Object Identification

Use of monoplotting for identifying objects in images.

This could be extremely useful for applications like security and surveillance.

Change Detection

Monoplotting to be used for detecting changes in objects or landscapes over time.

This could be extremely useful for applications like land use monitoring and environmental impact assessment.