From cce218627bbe6edba0d03e0ed9e2bf801df05d36 Mon Sep 17 00:00:00 2001
From: "James.Hester" <jxh@ansto.gov.au>
Date: Tue, 28 Jan 2020 19:52:54 +1100
Subject: [PATCH] Improved height interpolation for bad points near cliffs.
The original algorithm looked for good heights at the corners
of the rectangle with the target point at the centre. This fails
in pathological cases where only a single good point is available
in a non-corner position.
---
src/Lib/Array/array.cxx | 28 ++++++++++++++++++++++++----
1 file changed, 24 insertions(+), 4 deletions(-)
diff --git a/src/Lib/Array/array.cxx b/src/Lib/Array/array.cxx
index 5e1700df..faa67825 100644
--- a/src/Lib/Array/array.cxx
+++ b/src/Lib/Array/array.cxx
@@ -517,7 +517,9 @@ double TGArray::rectify_point(const int xgrid, const int ygrid, const std::vecto
//ygrid: grid units vertically
//Loop over corner points, if no points available, give up
int corners[4][2]; //possible corners
+ int sides[4][2]; //possible sides
int pt_cnt = 0;
+ int side_cnt = 0; //how many side points
double centre_long, centre_lat;
int original_height = get_array_elev(xgrid,ygrid);
centre_long = (originx + col_step*xgrid)/3600;
@@ -538,10 +540,22 @@ double TGArray::rectify_point(const int xgrid, const int ygrid, const std::vecto
corners[pt_cnt][1] = vert;
pt_cnt++;
}
+ if ( !is_bad_point( xgrid+horiz,ygrid,bad_points ) && //can trust height
+ check_points( test_long,centre_lat,centre_long,centre_lat ) ) { //same side
+ sides[side_cnt][0] = horiz;
+ sides[side_cnt][1] = 0;
+ side_cnt++;
+ }
+ if ( !is_bad_point( xgrid,ygrid+vert,bad_points ) && //can trust height
+ check_points( centre_long,test_lat,centre_long,centre_lat ) ) { //same side
+ sides[side_cnt][0] = 0;
+ sides[side_cnt][1] = vert;
+ side_cnt++;
+ }
}
} // end of search for corners
- if (pt_cnt == 0) return -9999; // no corners found
+ if ((pt_cnt == 0 ) && (side_cnt == 0)) return -9999; // no neighbouring good points
// Find two points that form a rectangle with a corner
int pt;
@@ -563,12 +577,18 @@ double TGArray::rectify_point(const int xgrid, const int ygrid, const std::vecto
// perhaps we have a concave cliff, just take the
// average of the known points
double totht = 0;
- for( int pti = 0; pti <pt_cnt; pti++ ) {
+ if (pt > 0) { // corner points available
+ for( int pti = 0; pti <pt_cnt; pti++ ) {
totht = totht + get_array_elev( xgrid+corners[pti][0],ygrid+corners[pti][1] );
+ }
+ height = totht/pt_cnt;
+ } else {
+ for( int pti = 0; pti <side_cnt; pti++ ) {
+ totht = totht + get_array_elev( xgrid+sides[pti][0],ygrid+sides[pti][1] );
+ }
+ height = totht/side_cnt;
}
- height = totht/pt_cnt;
-
} else {
// We have three points, calculate the height