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Added DEM data interpolation

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This commit is contained in:
Martin Tůma 2019-01-06 19:59:58 +01:00
parent 9fc9e24c01
commit 7f8b7297cf
1 changed files with 24 additions and 5 deletions
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29
src/data/dem.cpp
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@ -9,6 +9,21 @@
((samples) * (samples) * 2)
static qreal interpolate(qreal dx, qreal dy, qreal p0, qreal p1, qreal p2,
qreal p3)
{
return p0 * (1 - dx) * (1 - dy) + p1 * dx * (1 - dy) + p2 * dy * (1 - dx)
+ p3 * dx * dy;
}
static qreal value(int col, int row, int samples, const QByteArray data)
{
int pos = ((samples - 1 - row) * samples + col) * 2;
qint16 val = qFromBigEndian(*((const qint16*)(data.constData() + pos)));
return (val == -32768) ? NAN : val;
}
static qreal height(const Coordinates &c, const QByteArray data)
{
int samples;
@ -20,13 +35,17 @@ static qreal height(const Coordinates &c, const QByteArray data)
else
return NAN;
int lat = int(qRound((c.lat() - int(c.lat())) * (samples - 1)));
int lon = int(qRound((c.lon() - int(c.lon())) * (samples - 1)));
int row = (int)((c.lat() - (int)c.lat()) * (samples - 1));
int col = (int)((c.lon() - (int)c.lon()) * (samples - 1));
qreal dx = ((c.lon() - (int)c.lon()) * (samples - 1)) - col;
qreal dy = ((c.lat() - (int)c.lat()) * (samples - 1)) - row;
int pos = ((samples - 1 - lat) * samples + lon) * 2;
qint16 val = qFromBigEndian(*((const qint16*)(data.constData() + pos)));
qreal p0 = value(col, row, samples, data);
qreal p1 = value(col + 1, row, samples, data);
qreal p2 = value(col, row + 1, samples, data);
qreal p3 = value(col + 1, row + 1, samples, data);
return (val == -32768) ? NAN : val;
return interpolate(dx, dy, p0, p1, p2, p3);
}
QString DEM::fileName(const Key &key) const