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When to use 0 as a default value in raster?
For example, 0 may be used as a default value for cells that don’t have a valid value, but 0 may also be used to define valid values in the raster dataset. If this is the case you may need to define a mask. For more information, see the Mask environment setting or the Mask function.
Why are there homogeneous areas in a raster dataset?
Sometimes there are homogeneous areas in a raster dataset that the you do not want to display. These can include borders, backgrounds, or other data considered to not have valid values. Sometimes these are expressed as NoData values, although other times they may have real values.
Can you ignore nodata in a raster dataset?
The image on the left shows a NoData area with a black background, and the image on the right shows that same area using no color. When calculating the statistics for a raster dataset, you can choose to ignore any cells with NoData.
Where do I find the nodata value in ArcGIS?
In the ArcCatalog or the Catalog window, right-click the raster dataset and click Properties. On the General tab, under Raster Information is the NoData Value. Click the Edit button. The NoData Editor dialog box is opened.
What does each pixel represent in a raster dataset?
A raster dataset is composed of rows (running across) and columns (running down) of pixels (also know as cells). Each pixel represents a geographical region, and the value in that pixel represents some characteristic of that region.
What is the positional information in a raster image?
Normally this positional information consists of a coordinate for the top left pixel in the image, the size of each pixel in the X direction, the size of each pixel in the Y direction, and the amount (if any) by which the image is rotated.
How are raster data different from Vector features?
While vector features use geometry (points, polylines and polygons) to represent the real world, raster data takes a different approach. Rasters are made up of a matrix of pixels (also called cells), each containing a value that represents the conditions for the area covered by that cell (see figure_raster ).