INTRODUCTION

The TransLT library offers the following functionalities:

The transformation of coordinates between two coordinates systems;
Drawing polygons, paths or points in Google Earth.

Supported coordinate operations:

coordinates conversions (including the use of a map projection);
transformations with parameters: 1D, 2D or 3D;
polynomial transformations;
coordinates offset using grid files;
coordinates offset;
transformations with own formulas.

Coordinate transformation can be done based on a transformation model that is taken from a file, a model that contains operations with coordinates defined as transformation steps. If the transformation model supports the inverse calculation then the transformation can be done in reverse.

To create files with transformation models, we recommend that you use the main TransLT application where you can create and test transformation models. Also in the main application you can use the EPSG database to automatically create transformation steps. For this it is necessary to have a minimum of knowledge about coordinate reference systems (CRS) and about possible coordinate operations (CooOp) between these systems. Another important factor is the accuracy of the transformation that you need to know before making a new transformation model. It would be useful to have one or more points with coordinates in both systems to test the newly created model. If you can't handle it, please write to us at support@3dspace.ro, and if possible we will create the transformation model for you.

In the "Examples" folder you will find information about the implementation in Delphi and in Visual Studio, including the compiled executables. Also here you will find examples with some of the supported file types (transformation models, files with coordinates, files with graphic entities, etc.).

In the "Demo_TransLT_Library.exe" test application window you have exemplified how to make the settings in the "Language settings" and "Model properties" section and four usage examples in the sections: "Transformation test file", "Test for one point", "Test for entities file" and "Define entities, transform points and draw to Google Earth".

Note on the choice of operating system 32bit or 64bit: For 32-bit operating systems TransLT.Win32.dll library operate with 80 bits (10 bytes) allocated to real numbers, about 19 to 20 significant digits and for 64-bit operating systems TransLT.Win64.dll library operate with 64 bits (8 bytes) allocated to real numbers, about 15 to 16 significant digits.

Supported Conversions and Transformations

Coordinates conversions

Type of source coordinates		Type of target coordinates	EPSG method code
Geographical coordinates (φ,λ,h)	→	Geocentric cartesian coordinates (X,Y,Z)	9602
Geocentric cartesian coordinates (X,Y,Z)	→	Geographical coordinates (φ,λ,h)	9602
Geographical coordinates (φ,λ)	→	Plane coordinates (N,E) according to selected projection	-
Plane coordinates (N,E)	→	Geographical coordinates (φ,λ) according to selected projection	-

Projections

Cylindrical Projections
No.	Projection name	Applicable on ellipsoid	Applicable on spheroid	Reversible	EPSG method code
1	Cassini-Soldner	√	√	√	9806
2	Central Cylindrical		√	√	-
3	Cylindrical Equal Area (Normal)	√	√	√	9834, 9835
4	Cylindrical Equal Area (Oblique)	√	√	√	-
5	Cylindrical Equal Area (Transverse)	√	√	√	-
6	Equidistant Cylindrical	√	√	√	1028, 1029
7	Gall Stereographic Cylindrical		√	√	-
8	Hotine Oblique Mercator (Variant A)	√	√	√	9812
9	Hotine Oblique Mercator (Variant B)	√	√	√	9814, 9815
10	Hyperbolic Cassini-Soldner	√		√	9833
11	Laborde for Madagascar	√	√	√	9813
12	Mercator (1SP) (Variant A)	√	√	√	1026, 9804
13	Mercator (2SP) (Variant B)	√	√	√	9805
14	Mercator (2SP) (Variant C)	√	√	√	1044
15	Miller Cylindrical		√	√	-
16	Popular Visualisation Pseudo Mercator	√	√	√	1024
17	Swiss Oblique Mercator	√	√	√	-
18	Transverse Mercator	√	√	√	1111, 9807
19	Transverse Mercator (South Orientated)	√	√	√	9808
20	Transverse Mercator Zoned Grid System	√	√	√	9824
21	Tunisia Mining Grid	√	√	√	9816
22	Universal Transverse Mercator (UTM)	√	√	√	-
Pseudocylindrical Projections
23	Collignon		√	√	-
24	Eckert I		√	√	-
25	Eckert II		√	√	-
26	Eckert III		√	√	-
27	Eckert IV		√	√	-
28	Eckert V		√	√	-
29	Eckert VI		√	√	-
30	Equal Earth	√	√	√	1078
31	Fahey (Modified Gall)		√	√	-
32	Foucaut Sinusoidal		√	√	-
33	Foucaut Stereographic Equivalent		√	√	-
34	Hatano Asymmetrical Equal Area		√	√	-
35	Kavraiskiy V		√	√	-
36	Kavraiskiy VII		√	√	-
37	Loximuthal		√	√	-
38	McBride-Thomas Flat-Polar Parabolic (No. 5)		√	√	-
39	McBryde-Thomas Flat-Polar Quartic (No. 4)		√	√	-
40	McBryde-Thomas Flat-Polar Sine (No. 1)		√	√	-
41	McBryde-Thomas Flat-Polar Sinusoidal (No. 3)		√	√	-
42	McBryde-Thomas Flat-Pole Sine (No. 2)		√	√	-
43	Mollweide		√	√	-
44	Nell		√	√	-
45	Nell-Hammer		√	√	-
46	Pseudo Plate Carrée	√	√	√	9825
47	Putnins P1		√	√	-
48	Putnins P2		√	√	-
49	Putnins P3		√	√	-
50	Putnins P3p		√	√	-
51	Putnins P4 (Craster Parabolic)		√	√	-
52	Putnins P4p		√	√	-
53	Putnins P5		√	√	-
54	Putnins P5p		√	√	-
55	Putnins P6		√	√	-
56	Putnins P6p		√	√	-
57	Quartic Authalic		√	√	-
58	Sinusoidal (Sanson-Flamsteed)	√	√	√	-
59	Wagner I (Kavraiskiy VI)		√	√	-
60	Wagner II		√	√	-
61	Wagner III		√	√	-
62	Wagner IV		√	√	-
63	Wagner V		√	√	-
64	Wagner VI		√	√	-
65	Werenskiold I		√	√	-
66	Winkel I		√	√	-
67	Winkel II		√		-
Conic Projections
68	Albers Equal Area	√	√	√	9822
69	Bipolar conic of western hemisphere		√	√	-
70	Equidistant Conic	√	√	√	1119
71	Euler (Equidistant Conic)		√	√	-
72	Krovak Oblique Conformal Conic	√	√	√	9819
73	Krovak Oblique Conformal Conic (North Orientated)	√	√	√	1041
74	Krovak Oblique Conformal Conic Modified	√	√	√	1042
75	Krovak Oblique Conformal Conic Modified (North Orientated)	√	√	√	1043
76	Lambert Conformal Conic (1SP variant B)	√	√	√	1102
77	Lambert Conformal Conic (1SP)	√	√	√	9801
78	Lambert Conformal Conic (1SP) West Orientated	√	√	√	9826
79	Lambert Conformal Conic (2SP)	√	√	√	9802
80	Lambert Conformal Conic (2SP) Belgium	√	√	√	9803
81	Lambert Conformal Conic (2SP) Michigan	√	√	√	1051
82	Lambert Conic Near-Conformal	√		√	9817
83	Murdoch I (Equidistant Conic)		√	√	-
84	Murdoch II		√	√	-
85	Murdoch III (Equidistant Conic, minimum error)		√	√	-
86	Perspective Conic		√	√	-
87	Tissot		√	√	-
88	Vitkovskiy I (Equidistant Conic)		√	√	-
Pseudoconic Projections
89	Bonne (South Orientated)	√	√	√	9828
90	Bonne (Werner for lat.1sp = 90°)	√	√	√	9827
Polyconic Projections
91	American Polyconic	√	√	√	9818
92	International Map of the World (Modified Polyconic)	√	√	√	-
Azimuthal Projections
93	Azimuthal Equidistant (Charles F. F. Karney formulas)	√	√	√	1125
94	Azimuthal Equidistant (J.P. Snyder formulas)	√	√	√	-
95	Colombia Urban Projection	√	√	√	1052
96	Gnomonic		√	√	-
97	Guam (Azimuthal Equidistant)	√		√	9831
98	Lambert Azimuthal Equal Area	√	√	√	1027, 9820
99	Lee Oblated Stereographic		√	√	-
100	Local Orthographic	√	√	√	1130
101	Miller Oblated Stereographic		√	√	-
102	Mod. Stererographics of 48 U.S.		√	√	-
103	Mod. Stererographics of 50 U.S.	√	√	√	-
104	Mod. Stererographics of Alaska	√	√	√	-
105	Modified Azimuthal Equidistant (for Micronesia)	√		√	9832
106	Oblique Stereographic	√	√	√	9809
107	Orthographic	√	√	√	9840
108	Polar Stereographic Variant A (Universal)	√	√	√	9810
109	Polar Stereographic Variant B	√	√	√	9829
110	Polar Stereographic Variant C	√	√	√	9830
111	Stereographic (J.P. Snyder formulas)	√	√	√	-
112	Topocentric local	√	√	√	9836, 9837
113	Vertical Perspective	√	√		9838
114	Vertical Perspective (Orthographic case)	√	√		9839
Miscellaneous Projections
115	New Zealand Map Grid	√		√	9811
116	Van der Grinten		√	√	-

Transformations with parameters

Transformation type	Method	No. parameters	Invertible parameters	Reversible	EPSG method code
Transformation 1D	3D plane rotation	5		√	-
Transformation 1D	Translate to elevation	1	√	√	-
Transformation 2D	2D Helmert conformal transformation	4	√	√	9621, 9656
	2D Helmert conformal transformation with rotation origin	6		√	-
	2D orthogonal affine transformation	5		√	-
	2D non-orthogonal affine transformation	6	√	√	1049, 9623, 9624, 9666
Transformation 3D	3D Helmert, Bursa-Wolf method, conformal transformation	7	√	√	1031, 1032, 1033, 1035, 1037, 1038, 1132, 1133, 1140
	3D Helmert, Molodenski-Bedekas, conformal transformation	10			1034, 1039, 1061, 1062, 1063, 1065, 1066, 9603, 9604, 9605, 9606, 9607, 9636
	3D Helmert conformal transformation	7	√	√	-
	3D affine transformation	8			-
	3D affine transformation	9			-
	3D affine transformation with rotation origin	12			-
	Time-dependent 3D transformation, Bursa-Wolf method	15	√	√	1053, 1054, 1055, 1057, 1058, 1064
	Time-dependent 3D transformation, Helmert conformal	15		√	-

Polynomials transformations

Method name	Polynomials degree	Reversible	EPSG method code
General polynomial	2		9645
	3		9646
	4		9647
	6		9648
	13		-
Reversible polynomial	2	√	9649
	3	√	9650
	4	√	9651
	6	√	-
	13	√	9654
Complex polynomial	3		9652
Complex polynomial	4		9653
Madrid to ED50 polynomial	1		9617

Grid files

File extension	Format	File description	Applied to	EPSG method code
.94	Binary	Geoid model VERTCON format	h	9658
.asc	ASCII	Geoid model ASC format	h	1085
.b	Binary	NADCON 5, GEOCON, GEOCON 11 or VERTCON 3.0 format	(φ,λ,h), (φ,λ) or h	1074, 1075
.bin	Binary	Geoid model NGS format	h	1047, 1093, 1109, 1110, 1134, 1135
.byn	Binary	Geoid model GSD format	h	1060, 1090, 1126
.csv	ASCII	Geoid model NZLVD (New Zealand) or BEV AT (Austria) format	h	1071, 1080, 1081, 1089
.dat	Binary	NTv1 format	(φ, λ)	9614
.dat	ASCII	Geoid model DAT format	h	1059, 1082, 1098, 9661
.ggf	Binary	Geoid model Trimble GGF format	h	-
.grd	Binary	ANCPI 1D or 2D format (Romania)	(N, E) or h	-
.grd	ASCII	EGM96 geoid model, NGA format	h	1103, 1105, 1106, 9661
.gri	ASCII	Geoid model Gravsoft (OSGM15) format	h	1047, 1072, 1093, 1096
.gsb	Binary	NTv2 format, files with multiple grids that cover more areas, the gridscan have sub-grids attached	(φ, λ) or h	1048, 1083, 9614, 9615
.gsf	ASCII	Geoid model Carlson SurvCE GSF format	h	-
.gtx	Binary	Geoid model GTX format	h	1084, 1088, 1121, 1122, 9665
.gvb	Binary	Point motion NTv2_Vel format, files with multiple grids that cover more areas, the gridscan have sub-grids attached	(φ, λ, h)	1070, 1113, 1114, 1141
.gz	Archive	EGM2008 geoid model, NGA format	h	1025, 1092
.json	ASCII	Triangulated model, TIN format	(N,E) or H	1137, 1138
.las / .los	Binary	NADCON format	(φ, λ)	9613
.lla	ASCII	Latitude and longitude corrections in PROJ4 format	(φ, λ)	-
.mnt	ASCII	IGN with MNT format	(φ, λ) or h	1073, 1087, 1095
.sid	ASCII	Geoid model NZGV format	h	1030
.txt	ASCII	IGN with TXT format	(φ, λ) or h	1087, 1094, 9664
.txt	ASCII	OSTN02/OSGM02 or OSTN15/OSGM15 1D or 3D format	(N,E,H), (N,E) or H	1045, 1097, 9633, 9663
.txt	ASCII	Geoid model CING11 format	h	1050, 1082, 1091, 1098
gugik*.txt	ASCII	GUGiK PL TXT format	(φ, λ, h) or h	1099, 1100, 1101
.isg.txt	ASCII	Geoid model ISG format	h	1117, 1118
.zip	Archive	Deformation model NZGD2000 format	(φ,λ,h), (φ,λ) or h	1079
Grid interpolation methods: Bilinear, Bicubic spline and Biquadratic.

Offset methods

Method name	Applied to	Reversible	EPSG method code
Longitude rotation	λ	√	9601
Vertical Offset	h	√	1131, 1136, 9616
Vertical Offset and Slope	h	√	1046
Geographic 2D offsets	(φ, λ)	√	9619
Geographic 2D with Height Offsets	(φ, λ, h)	√	9618
Geographic 3D offsets	(φ, λ, h)	√	9660
Geographic 3D to 2D conversion	h = 0.0	√	9659
Geographic 2D axis order reversal	(φ, λ)	√	9843
Geographic 3D axis order change	(φ, λ)	√	9844
Change of vertical axis direction	h	√	-
Change of horizontal axes directions	(φ, λ), (N, E)	√	-
Change of all axes directions	(N, E, H), (X, Y, Z)	√	-
Change of vertical axis unit	h	√	1069, 1104
Change of horizontal axes units	(φ, λ), (N, E)	√	-
Change of all axes units	(N, E, H), (X, Y, Z)	√	-
Points motion (ellipsoidal)	(φ, λ, h)	√	1067
Change zero-tide height to mean-tide height	h	√	1107

Predefined constants and functions for transformations with own formulas

Name	Description	Example
pi	Pythagorean number pi = 3.141592655...
e	Euler number e = 2.71828182...
abs	absolute value	abs(-1.0) = 1.0 abs(1.0) = 1.0
sqrt	square root	sqrt(2.0) = 1.41421356...
pow(B,n)	raises base B to power n	pow(25,1.5) = 125.0
ln	natural logarithm	ln(e) = 1.0
sin	sine calculated for angles in radians	sin(pi/2) = 1.0
cos	cosine calculated for angles in radians	cos(pi/2) = 0.0
tan	tangent calculated for angles in radians	tan(pi/4) = 1.0
asin	arcsine, the return value will fall in the range [-pi/2, pi/2]	asin(1.0) = pi/2
acos	arccosine, the return value will fall in the range [0, pi/2]	acos(0.0) = pi/2
atan	arctangent, the return value will fall in the range [-pi/2, pi/2]	atan(1.0) = pi/4
atan2(dy,dx)	arctangent angle and quadrant, the return value will fall in the range [-pi, pi](all quadrants)	atan2(-5.0,0.0) = -pi/2
sinh	hyperbolic sine	sinh(ln(2.0)) = 0.75
cosh	hyperbolic cosine	cosh(ln(2.0)) = 1.25
tanh	hyperbolic tangent	tanh(ln(2.0)) = 0.6
asinh	hyperbolic arcsine	asinh(0.75) = ln(2.0)
acosh	hyperbolic arccosine	acosh(1.25) = ln(2.0)
atanh	hyperbolic arctangent	atanh(0.6) = ln(2.0)
rtod	conversion from radians to decimal degrees	rtod(pi) = 180.0
dtor	conversion from decimal degrees to radians	dtor(180.0) = pi