Indian Remote Sensing Satellite Cartosat-1: Technical features and data products


  1. Image Map Data Products (IMDP):
    IMDP containing co-registered ortho corrected Cartosat-PAN raster images with one or more layers of cartographic vector information (available apriori or derived from Cartosat image) including a layer containing ASCII text strings as labels of vector elements, with necessary additional ancillary information shall be generated and supplied to the users. The following types of products are planned.

    1. 2-D Satellite Image Map Products in conventional map projection or with user-defined projection parameters.


    2. 2.5-D Satellite Image Map Products, representing the terrain elevation for one or more fixed, standard perspective view angles possibly with artificially exaggerated scaling effects incorporated to show the terrain relief.


    3. 3-D Satellite Image Map Products, optionally including the 3-D viewing software as a part of the product.

    All the types of image map products are corrected Cartosat-PAN images, either on stand alone basis or desirably fused with available multi-spectral images with comparable spatial resolution as the base raster image.


  2. DEM Data Products:
    The following types of DEM Data Products are planned to be generated.

    Type I: As computed originally:
    • As randomly distributed point heights as computed originally.
    • As triangulated Irregular Network (TIN) retaining all the originally computed points,
      • as they are.
    • As progressively sampled rectangular grids, retaining all the originally computed points, as they are

    Type II: As completed originally and incorporating break-lines:
    • As a set of irregular point heights and break lines showing the surface discontinuities
    • As a TIN model retaining all the originally computed points as they are; and in addition incorporating break lines, either as part of the TIN edges (referred as soft break lines) or as add-on specification (referred as hard break lines) indicating abrupt surface changes.
    • As progressively sampled rectangular grids, retaining all the originally computed points, as they are plus the break lines manually identified.

    Type III: As interpolated, mostly regular
    • As a rectangular grid, generated by a suitable interpolation algorithm from the initial set of irregular points and break lines.
    • As contours, connecting points of equal height at varying intervals.
    • As a set of parallel vertical profiles, in any user desired direction.

  3. Coarse DEM Generation (CDG):
    It is necessary to carryout scene based processing for mono mode data acquisition for either fore or aft camera towards generating level 1 or level 2 products with minimum internal distortion as per the quality requirements. However, since the Cartosat cameras are mounted onboard the spacecraft in non-nadir viewing configuration, this can be achieved by carrying out terrain corrections apart from the system level corrections. Hence it is necessary to have DEM for all coverage for this purpose. Cartosat-1 being a stereo mission, allows for building such database on a pass or a pass segment basis.
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