The resolution of raster data refers to the size of each individual cell (pixel) within the raster dataset and how these cells relate to the real-world size or area they represent. It also describes the ratio of screen pixels to image pixels at a given map scale.
Here's a breakdown:
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Cell Size: This is the most fundamental aspect of raster resolution. A smaller cell size means higher resolution, as each cell represents a smaller area on the ground, allowing for more detail. A larger cell size means lower resolution, with each cell representing a larger area and less detail.
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Spatial Resolution: This is often what people are referring to when they talk about raster resolution. It is the ground area represented by each cell. For example, a 10-meter spatial resolution means each cell represents a 10m x 10m area on the Earth's surface.
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Relationship to Map Scale: When viewing a raster dataset on a screen, the map scale influences how the raster resolution is displayed. For example, if one screen pixel is displaying the data resampled from nine image pixels, the raster resolution is considered to be 1:9.
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Implications of Resolution:
- Detail: Higher resolution rasters capture finer details and can represent smaller features more accurately.
- Data Volume: Higher resolution rasters require significantly more storage space because they contain more cells.
- Processing Time: Processing higher resolution rasters often takes longer due to the increased data volume.
- Appropriateness: The appropriate resolution for a raster depends on the application. For example, regional-scale mapping might be adequately served by a coarser resolution, while detailed site-specific analysis requires higher resolution data.
In summary, raster resolution dictates the level of detail captured in the data and is a crucial factor to consider when acquiring, analyzing, and displaying raster datasets.
