From: Martin D. <mar...@no...> - 2005-04-05 09:09:30
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Emin Hasanov a =E9crit : > My map is spread over 4 different zones > (38T, 39T, 38S, 39S), but my understanding is that I can only georefere= nce > 2 corners of the raster and use one single projection for the whole map. This is the default way. But if you want more sophesticated mapping, you=20 can. There is 2 variants of GridCoverage2D constructors: GridCoverage2D(..., CoordinateReferenceSystem, Envelope, ...) (this is the easiest way), and: GridCoverage2D(..., CoordinateReferenceSystem, MathTransform, ...) The second case gives you more freedom. But you have to setup (again)=20 yours own MathTransform implementation, which would be a composition of=20 4 AffineTransforms in adjacent tiles. > However, when I convert lat/long to meters they do not grow linearly, b= ut > are reset to smaller values once you cross border between zones. Hence = I > am not sure how to project this properly. See above. A custom MathTransform implementation could do the work. We=20 could provide a standard class in Geotools for that, but it is not yet do= ne. > Is there a way to calibrate raster using approach similar to the progra= ms > like OziExplorer? One need to choose several points on the map and > identify their lat/long values and OziExplorer automatically identifies > everything else for you. It depends what you means by identifying everything else for you. You=20 may use polynomial warping. You may use Delaunay triangulation. There is=20 a variety of technics. We implemented Delaunay triangulation in ours own=20 laboratory, but this code is not yet on Geotools (it may move there later= ). Martin. |