moving_window_indicator
Prototype
template<class Raster, class IndicatorGenerator>
auto moving_window_indicator(Raster raster, const circle& window
, IndicatorGenerator indicator_generator);
template<class Raster, class IndicatorGenerator>
auto moving_window_indicator(Raster raster, const square& window
, IndicatorGenerator indicator_generator);
template<class Raster, class IndicatorGenerator>
auto moving_window_indicator(Raster raster, const square_edge& window
, IndicatorGenerator indicator_generator);
Description
Creates an alternate view of the input raster Raster that for each element returns a statistic (indicator) calculated for the window surrounding it. Three different types of window are supported square, circle and square_edge.
These are simple structs that are constructed using a single argument (radius).
Definition
<pronto/raster/moving_window_indicator.h> (open in Github)
Requirements on types
Raster must implement the RasterView concept. IndicatorGenerator must implement the IndicatorGenerator concept.
Preconditions
raster must be initialized
Complexity
The complexity of this function is O(1), but the complexity of iterating over the moving_window_view depends on the window type used. For square windows it is O(n) and for circular windows it is O(n*r) where n is the size of the raster and r is the radius of the window.
Example of use
//example_moving_window_indicator.cpp
#include <pronto/raster/io.h>
#include <pronto/raster/moving_window_indicator.h>
#include <pronto/raster/plot_raster.h>
#include <pronto/raster/indicator/mean.h>
namespace pr = pronto::raster;
int main()
{
auto raster = pr::create_temp<int>( 3, 4, GDT_Byte);
auto i = 0;
for (auto&& v : raster) {
i = (i + 3) % 7;
v = i;
}
auto window_mean = pr::moving_window_indicator(raster, pr::square(1),
pr::mean_generator<int>{});
plot_raster(raster);
plot_raster(window_mean);
plot_raster(window_mean.sub_raster(1,1,2,2));
return 0;
}
Output:
Rows: 3, Cols: 4, Value type: int
3 6 2 5
1 4 0 3
6 2 5 1
Rows: 3, Cols: 4, Value type: class std::optional<double>
3.5 2.66667 3.33333 2.5
3.66667 3.22222 3.11111 2.66667
3.25 3 2.5 2.25
Rows: 2, Cols: 2, Value type: class std::optional<double>
3.22222 3.11111
3 2.5