GDAL

gdalgeoloc.h
1/******************************************************************************
2 *
3 * Project: GDAL
4 * Purpose: Implements Geolocation array based transformer.
5 * Author: Even Rouault, <even.rouault at spatialys.com>
6 *
7 ******************************************************************************
8 * Copyright (c) 2022, Planet Labs
9 *
10 * SPDX-License-Identifier: MIT
11 ****************************************************************************/
12
13#ifndef GDALGEOLOC_H
14#define GDALGEOLOC_H
15
16#include "gdal_alg_priv.h"
17
18/************************************************************************/
19/* GDALGeoLoc */
20/************************************************************************/
21
24 template <class Accessors> struct GDALGeoLoc
25{
26 static void LoadGeolocFinish(GDALGeoLocTransformInfo *psTransform);
27
28 static bool GenerateBackMap(GDALGeoLocTransformInfo *psTransform);
29
30 static bool PixelLineToXY(const GDALGeoLocTransformInfo *psTransform,
31 const int nGeoLocPixel, const int nGeoLocLine,
32 double &dfX, double &dfY);
33
34 static bool PixelLineToXY(const GDALGeoLocTransformInfo *psTransform,
35 const double dfGeoLocPixel,
36 const double dfGeoLocLine, double &dfX,
37 double &dfY);
38
39 static bool ExtractSquare(const GDALGeoLocTransformInfo *psTransform,
40 int nX, int nY, double &dfX_0_0, double &dfY_0_0,
41 double &dfX_1_0, double &dfY_1_0, double &dfX_0_1,
42 double &dfY_0_1, double &dfX_1_1,
43 double &dfY_1_1);
44
45 static int Transform(void *pTransformArg, int bDstToSrc, int nPointCount,
46 double *padfX, double *padfY, double * /* padfZ */,
47 int *panSuccess);
48};
49
52 bool GDALGeoLocExtractSquare(const GDALGeoLocTransformInfo *psTransform, int nX,
53 int nY, double &dfX_0_0, double &dfY_0_0,
54 double &dfX_1_0, double &dfY_1_0, double &dfX_0_1,
55 double &dfY_0_1, double &dfX_1_1, double &dfY_1_1);
56
57 void GDALInverseBilinearInterpolation(const double x, const double y,
58 const double x0, const double y0,
59 const double x1, const double y1,
60 const double x2, const double y2,
61 const double x3, const double y3,
62 double &i, double &j);
63
64/************************************************************************/
65/* ShiftGeoX() */
66/************************************************************************/
67
68// Avoid discontinuity at anti-meridian when interpolating longitude
69// dfXRef is a "reference" longitude, typically the one of 4 points to
70// interpolate), towards which we apply a potential +/- 360 deg shift.
71// This may result in a value slightly outside [-180,180]
72 static double ShiftGeoX(const GDALGeoLocTransformInfo *psTransform,
73 double dfXRef, double dfX)
74{
75 if (!psTransform->bGeographicSRSWithMinus180Plus180LongRange)
76 return dfX;
77 // The threshold at 170 deg is a bit arbitrary. A smarter approach
78 // would try to guess the "average" longitude step between 2 grid values
79 // and use 180 - average_step * some_factor as the threshold.
80 if (dfXRef < -170 && dfX > 170)
81 return dfX - 360;
82 if (dfXRef > 170 && dfX < -170)
83 return dfX + 360;
84 return dfX;
85}
86
87#endif