[GRASS5] libgrass++

[Radim Blazek]

libgrass++ was written for first, version of GRASS support in QGIS.
It was later partialy used in GRASS-QGIS provider/plugins and
partialy substituted by GDAL, so it is not developed any more.

You have to modify GRASSRaster::GetRowRGB to some GRASSRaster::GetRow.

GetValue() was realy for one or few points like d.what.rast.

Radim


On Thursday 08 July 2004 16:32, Sabine Grabner wrote:
> hello, i try to read a raster (1885 by 1382) with GetValue(..) of
> GRASSRaster.h of Grass++ library. it would take more than 30 minutes just
> to read one raster! but unfortunately after about 500 rows i get a core
> dump and the display has only scaring signs till i booted again.
>
> obviously GetValue() does a lot of Open() and Close() what might make it
> slow. also i have to call this method for each pixel instead read data of
> required window at once.
>
> what shall i do to speed up this method and is there also a method to write
> a grass raster after treating the data?
>
> thank you. sabine
>
>
> main():
> 	int n = 5227350;
> 	int s = 5180225;
> 	int w = 179000;
> 	int e = 213550;
> 	int xres = 25;
> 	int yres = 25;
> 	int cols = (int)(e - w) / xres;
> 	int rows = (int)(n - s) / yres;
>
> 	Window::setStandard(cols, rows, w, n, xres, yres);
>
> 	string filename = "dem";
> 	Raster raster = Raster(filename);
>
> Raster::Raster(string filename)
> {
> ..
> 	char* gisdbase = "/home/sabine/diss/grassdata";
> 	char* location = "oetztal";
> 	//char* map = filename;
>
> 	char* map = "dem";
> 	GRASSRaster grassraster(gisdbase, location, map);
>
> grassraster.SetWindow(Window::getN(),Window::getS(),Window::getE(),Window::
>getW(),Window::getYSize(),Window::getXSize()); grassraster.Open();
>
> 	for (int y = 0; y < data.size(); y++)
> 	{
> 		for (int x = 0; x < data[y].size(); x++)
> 		{
> 			double xx = Window::getW() + x *
> Window::getXResolution();
> 			double yy = Window::getN() - y *
> Window::getYResolution();
> 			grassraster.GetValue(xx, yy, &data[y][x]);
>
> 		}
> 		cout << y << ". row of " << Window::getYSize() << "\n";
> 	}
> 	grassraster.Dump();
> 	grassraster.Close();
> }
>
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