「ラスタデータとは何？」の版間の差分
(ページの作成: <H2> What is raster data? </H2> <P> Raster data in GIS are matrices of discrete cells that represent features on, above or below the earth's surface. Each cell in the raster gri…) |
([ラスタデータとは何？]箇所のタグ調整) |
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Raster data in GIS are matrices of discrete cells that represent features on, | Raster data in GIS are matrices of discrete cells that represent features on, | ||
above or below the earth's surface. Each cell in the raster grid is the same | above or below the earth's surface. Each cell in the raster grid is the same | ||
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matrix. | matrix. | ||
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Unlike vector data, raster data typically do not have an associated database | Unlike vector data, raster data typically do not have an associated database | ||
record for each cell. They are geocoded by its pixel resolution and the x/y | record for each cell. They are geocoded by its pixel resolution and the x/y | ||
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the data correctly in the map canvas. | the data correctly in the map canvas. | ||
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QGIS makes use of georeference information inside the raster layer (e.g. GeoTiff) | QGIS makes use of georeference information inside the raster layer (e.g. GeoTiff) | ||
| − | or in an appropriate world file to properly display the data. | + | or in an appropriate world file to properly display the data. |
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2009年9月9日 (水) 00:04時点における版
What is raster data?
Raster data in GIS are matrices of discrete cells that represent features on, above or below the earth's surface. Each cell in the raster grid is the same size, and cells are usually rectangular (in QGIS they will always be rectangular). Typical raster datasets include remote sensing data such as aerial photography or satellite imagery and modelled data such as an elevation matrix.
Unlike vector data, raster data typically do not have an associated database record for each cell. They are geocoded by its pixel resolution and the x/y coordinate of a corner pixel of the raster layer. This allows QGIS to position the data correctly in the map canvas.
QGIS makes use of georeference information inside the raster layer (e.g. GeoTiff) or in an appropriate world file to properly display the data.
