Changes between Version 35 and Version 36 of WKTRaster/Documentation01
- Timestamp:
- 12/10/09 08:53:45 (15 years ago)
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WKTRaster/Documentation01
v35 v36 271 271 f) '''a raster object coverage resulting from the rasterization of a vector coverage.''' Each vector feature becomes a small raster with the same extent as the original vector feature. This type of coverage is not necessarily complete, nor rectangular; tiles should be of different sizes and might overlap. It all depends on the characteristics of the vector layer being rasterized. An exhaustive (or continuous) layer of mutually exclusive geometries (without gaps or holes like a forest cover) would result in a raster object coverage in which significant pixels (withdata values) would not overlap, but non-significant pixels (nodata values) would. On the other end of the spectrum, a discontinuous layer of mutually exclusive geometries (like a lake or building layer) would result in a coverage of mostly disjoint raster objects. 272 272 273 Table 1 - Characteristics of different raster table arrangements: 273 '''''Table 1 - Characteristics of possible different raster table arrangements in PostGIS WKT Raster''''' 274 274 275 275 || '''Arrangement''' || '''Global shape of[[BR]]composing raster''' || '''Missing tiles[[BR]]possible''' || '''Same size[[BR]]tiles''' || '''Tile overlap[[BR]]possible''' || '''Form a[[BR]]coverage?''' || … … 281 281 ||'''f) raster object coverage''' || any || no real tiles || no real tiles || yes || yes || 282 282 283 283 '''''Figure 1 - Different possible raster table arrangements in PostGIS WKT Raster''''' 284 285 [[Image(WKTRasterArrangements.gif)]] 284 286 285 287