Raster Data Operations: Clip, Mosaic, and Data Extraction (Especially for GATE-Geospatial 2022)

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Raster data analysis can be performed at the level of individual cells, or groups of cells, or cells within an entire raster. Some raster data operations use a single raster; others use two or more rasters. Raster data analysis also depends on the type of cell value

  • Operations for raster data management include clip and mosaic.
  • Operations for raster data extraction include use of a data set, a graphic object, or a query expression to create a new raster by extracting data from an existing raster.
  • Operations for raster data generalization include aggregate and region group.

Clip for Vector Data

In GIS, to clip is to overlay a polygon on one or more target features (layers) and extract from the target feature (or features) only the target feature data that lies within the area outlined by the clip polygon. The clipped data becomes a new feature.

Clipping to form a new feature class creates a study area or specific area of interest that is an important function when working in GIS.

Illustration 2 for Clip_for_Vector_Data

Mosaic

The mosaic dataset was developed to manage and deploy imagery information products in a time-sensitive workflow environment. It consists of:

  • A catalog that provides the source of the pixels and footprints of the rasters.
  • A feature class that defines the boundary.
  • A set of mosaicking rules that are used to dynamically mosaic the rasters.
  • A set of properties used to control the mosaicking and any image extraction.
  • A table for logging during data loading and other operations.
  • Optionally, a seam line feature class for seam line mosaicking.
  • Optionally, a color correction table that defines the color mapping for each raster in the raster catalog.
Illustration 3 for Clip_for_Vector_Data

Data Extraction Using Mask

Mask is used for raster data set and clip is used in vector data and please read the following figures and results for better understanding and the outputs are represented

This Figure Shows Input Raster and Output Raster with Circle

In above figure, a circle, shown in white, is used to extract cell values from the input raster (a) . The output (b) has the same area extent as the input raster but has no data outside the circular area.

Figure Shows an Analysis Mask, Input Raster and Output Raste …

In figure, an analysis mask (b) is used to clip an input raster (a) . The output raster is (c) , which has the same area extent as the analysis mask.

Developed by: