- In order to load files in tables easier you can drag with the mouse from the Windows Explorer a file over a table and then drop it, in this case the file will be added in the table. By dragging another file over the same table the table will be completed with the second file. Also with this procedure of drag and drop you can add files to the list of files from the window Coordinates files conversions (external calling).
- For files bigger than approximately 100 000 points we recommend their conversion by externally calling the program from the contextual menu of Windows Explorer for files with the extension recognized by TransLT. This limitation that refers to the number of points depends on the memory of your computer. The allocation of the extensions for the file that can be converted with TransLT can be made using the button Options - General Tab.
- When reading the coordinates from a file, check if they observe the allocated value on the column, for example if they observe the order N, E, H or E, N, H (according to the configuration) for the points in the projection plane or φ, λ, h for the points with the coordinates on the ellipsoid. For φ, λ coordinates reading is made correctly both for angles in decimal degrees as for angles in sexagesimal degrees.
- The correct reading from the file of the geographic coordinates φ and λ expressed in sexagesimal degrees is accepted for the following characters that delimitate the degrees, minutes and seconds: <°>, <d>, <o>,, <'>, <">, <_> or <~>. The space character is accepted for delimitation only in the case of the .csv files. For example an angle can be written as: 44°08'12.34567”, 44”08”12.34567, 44_08_12.34567, 88d12'34.5678"W, 47°12'34.5678"N etc.
- When manually introducing in tables the sexagesimal degrees, the separation symbol can be any of the characters used for the identification of degrees, minutes or seconds or, you can use space key to automatically introduce it.
- The name of the points can contain spaces only in the case of the CSV files. When the name of the points contains spaces and these are saved in a format different from CSV the space character is replaced with the "_" character.
- A point from table is considered valid only if its name (number) is introduced.
- 3D transformations must be used carefully because the elevations of the points influence the transformation. Thus, if the H orthometric heights that are imprecisely determined are introduced in the transformation or if big undulations of the geoid exist in the area where the work is being done, these elevations will adversely influence the determination of the coordinates (N, E) in the projection plane.
- If the determination of elevations isn’t important for the job that you are performing, the coordinates (N, E) being enough, we recommend using the 2D conformal transformation with 4 or 6 parameters to eliminate the errors that can appear because of the point elevations from the triangulation network. Also in this case, if you need a 3D transformation with 7 parameters because you would use them when measuring with the GPS through the RTK method then we recommend excluding the ellipsoidal elevations from the transformation from (φ, λ, h) to (X, Y, Z).
- If you wish to calculate the elevation as well we recommend the Stepwise transformation model that is defined as an example when installing. Through this method (beside the necessary conversions to pass from a system to another) there are 3 transformations made and namely: a conformal 3D approximate transformation with 7 or 10 parameters (Bursa-Wolf or Molodenski-Badekas), a conformal 2D transformation with 4 or 6 parameters and at the end a 1D transformation through which the 3D plane rotates to approximate the elevations. Through this method the coordinates (N, E) from the projection plane aren’t influenced by the point elevations. For example you can use for the (N, E) determinations the points from the triangulation network and for the transformation on the elevations (H) leveling markers.
- In this program there are also included transformations that are not recommended for the transformations used in the work method with the GPS technology. These can be used in other domains, for example the affine 3D transformation with 8 parameters can be used to transform a model from 3D space into an image in 2D space. Another domain in which it can be used, for example, the affine 3D transformation with 9 or 12 parameters is reconstructing the relief (3D model) of a building facade. Another example, the affine 2D transformations with 5 or 6 parameters can be used for georeferencing images.
- If you want to make comparisons with other programs we recommend comparing transformed coordinates. The comparison of parameters values is not relevant because some programs use the iterative algorithm where is not the case or the accuracy of determination is not the same. For example, if you wish to use the parameters determined with the LGO program from Leica, the following differences must be taken in account: 1). For the 2D transformation with 6 parameters the angle of rotation must be introduced reversed; 2). For the 1D transformation with 5 parameters the angles presented in the LGO report are not the same and for this reason the parameters must be recalculated on common points; 3). For the forward and inverse conversion from (φ, λ) to (N, E) in the stereographic projection (for Romania) the method with the constant coefficients must be chosen.