From 6a2c2a65ce3484d93fc035ad6ac41e076450cdbd Mon Sep 17 00:00:00 2001
From: Karsten Rink <karsten.rink@ufz.de>
Date: Fri, 30 May 2014 22:36:46 +0200
Subject: [PATCH] added function to Raster to return value at point coordinates
---
GeoLib/Raster.cpp | 21 +++++++++++++++++++++
GeoLib/Raster.h | 5 +++++
2 files changed, 26 insertions(+)
diff --git a/GeoLib/Raster.cpp b/GeoLib/Raster.cpp
index c0623bd9c5b..1ccb616f93e 100644
--- a/GeoLib/Raster.cpp
+++ b/GeoLib/Raster.cpp
@@ -105,6 +105,27 @@ Raster* Raster::getRasterFromSurface(Surface const& sfc, double cell_size, doubl
return new Raster(n_cols, n_rows, ll[0], ll[1], cell_size, z_vals, z_vals+n_cols*n_rows ,-9999);
}
+double Raster::getValueAtPoint(const GeoLib::Point &pnt)
+{
+ const double* coords (pnt.getCoords());
+
+ if (coords[0]>=_ll_pnt[0] && coords[0]<(_ll_pnt[0]+(_cell_size*_n_cols)) &&
+ coords[1]>=_ll_pnt[1] && coords[1]<(_ll_pnt[1]+(_cell_size*_n_rows)))
+ {
+ int cell_x = static_cast<int>(floor((coords[0] - _ll_pnt[0])/_cell_size));
+ int cell_y = static_cast<int>(floor((coords[1] - _ll_pnt[1])/_cell_size));
+
+ // if node outside of raster use raster boundary values
+ cell_x = (cell_x < 0) ? 0 : ((cell_x > static_cast<int>(_n_cols)) ? (_n_cols-1) : cell_x);
+ cell_y = (cell_y < 0) ? 0 : ((cell_y > static_cast<int>(_n_rows)) ? (_n_rows-1) : cell_y);
+
+ size_t index = cell_y*_n_cols+cell_x;
+ if (fabs(_raster_data[index] - _no_data_val) > std::numeric_limits<float>::epsilon())
+ return _raster_data[index];
+ }
+ return _no_data_val;
+}
+
void Raster::writeRasterAsASC(std::ostream &os) const
{
// write header
diff --git a/GeoLib/Raster.h b/GeoLib/Raster.h
index 6e4c7acad9c..2cf4c3f4403 100644
--- a/GeoLib/Raster.h
+++ b/GeoLib/Raster.h
@@ -96,6 +96,11 @@ public:
*/
const_iterator end() const { return _raster_data + _n_rows*_n_cols; }
+ /**
+ * Returns the raster value at the position of the given point.
+ */
+ double getValueAtPoint(const GeoLib::Point &pnt);
+
~Raster();
/**
--
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