Editing Raster graphics (section)

==Data model==
[[File:Raster graphic fish 20x23squares sdtv-example.png|thumb|A simple raster graphic]]

The fundamental strategy underlying the raster data model is the [[tessellation]] of a plane, into a two-dimensional array of squares, each called a ''cell'' or ''[[pixel]]'' (from "picture element"). In [[digital photography]], the plane is the [[visual field]] as projected onto the [[image sensor]]; in [[computer art]], the plane is a virtual canvas; in [[geographic information systems]], the plane is a [[Map projection|projection]] of the Earth's surface. The size of each square pixel, known as the ''resolution'' or ''support'', is constant across the grid.
Raster or ''gridded data'' may be the result of a [[gridding]] procedure.

A single numeric value is then stored for each pixel. For most images, this value is a visible color, but other measurements are possible, even numeric codes for qualitative categories. Each raster grid has a specified ''pixel format'', the data type for each number. Common pixel formats are [[binary image|binary]], [[gray-scale]], [[palette (computing)|palettized]], and [[RGB color model|full-color]], where [[color depth]]<ref name="MSDN_bitmapTypes">{{cite web 
|url=https://docs.microsoft.com/en-us/dotnet/framework/winforms/advanced/types-of-bitmaps?view=netframework-4.7.2 
|title=Types of Bitmaps 
|date=29 March 2017 
|website=Microsoft Docs 
|publisher=Microsoft 
|access-date=1 January 2019 
|quote=The number of bits devoted to an individual pixel determines the number of colors that can be assigned to that pixel. For example, if each pixel is represented by 4 bits, then a given pixel can be assigned one of 16 different colors (2^4 = 16). 
|archive-date=2 January 2019 
|archive-url=https://web.archive.org/web/20190102143109/https://docs.microsoft.com/en-us/dotnet/framework/winforms/advanced/types-of-bitmaps?view=netframework-4.7.2 
|url-status=live 
}}</ref> determines the fidelity of the colors represented, and [[color space]] determines the range of color coverage (which is often less than the full range of human [[color vision]]). Most modern color raster formats represent color using 24&nbsp;bits (over 16&nbsp;million distinct colors), with 8&nbsp;bits (values 0–255) for each [[color channel]] (red, green, and blue). The digital sensors used for [[remote sensing]] and [[astronomy]] are often able to detect and store wavelengths beyond the [[visible spectrum]]; the large [[charge-coupled device|CCD]] bitmapped sensor at the [[Vera C.&nbsp;Rubin Observatory]] captures 3.2&nbsp;gigapixels in a single image (6.4&nbsp;GB raw<!-- from 1.28 PB/year / 200,000 images/year -->), over six [[channel (digital image)|color channels]] which exceed the [[electromagnetic spectrum|spectral]] range of human color vision.