Coordinate System
The dialog Coordinate System is available from the Options|Coordinate System menu. By default, no global coordinate system is selected. This corresponds to the presently used coordinate system in CadnaA as specified via Options| Limits-dialog (see Limits).
Dialog Coordinate System
EPSG-Code
EPSG codes represent a system of globally unique codes of geodetic datasets. A geodetic coordinate system is clearly identified by its EPSG code (consisting of a 4- to 5-digit code number). Enter the EPSG code in order to select the appropriate coordinate/reference system.
Note
EPSG stands for „European Petroleum Survey Group Geodesy“, a working group of the European oil and gas exploration companies that introduced this designation system.
Examples
Examples of EPSG codes (no warranty)
| Coordinate-/Reference System | EPSG-Code/s |
|---|---|
| Gauß-Krüger-Zones 2 to 5 DGHN | 31466 to 31469 |
| UTM-Zones ETRS89 32N and 33N | 25832 anmd 25833 |
Coordinate & Reference System
Click on the arrow to the right of list boxes „System“ and „Reference“ to display all available national and international coordinate systems and reference points. Select appropriate items from the lists sorted in alphabetical order.
Example
Path: Examples\ Graphic\ Geodetic Coordinate Systems
For more information on the coordinate and reference systems available by default see the stated directory.
Reference Systems according to NTv2 Standard
In addition to the default reference systems, reference systems based on the NTv2 standard (National Transformation version 2) can also be used.
The conversion files (file type *.gsb, „grid shift binary“) required for conversion from other reference systems (see also chapter Coordinate Transformation, Geodetic Transformation) are not supplied with CadnaA. Prior to conversion copy the appropriate gsb-files into the CadnaA installation directory (default path, e.g.: C:\Program Files\Datakustik\ CadnaA64\NTv2).
List Box „Meridian Strip“
On list box „Meridian Strip“ the relevant strip can be selected. The maximum is 120 strips/zones with 3 degrees longitudinal length each. Different coordinate systems make use of different strip numbers (e.g. UTM: 60 zones with 6° each, GK: 120 strips with 3° or 60 strips with 6° each). With "(auto)" selected the strip number (zone) will be extracted from the first 2 digits of the coordinate entered.
When the imported bitmap extends across the border of a strip or zone, the option "(auto)" may cause a wrong import and display. Select in this case a valid strip or zone.
Offsets
By entering offsets (X,Y) coordinates translatoric shifts can be considered. The offset-values entered will be added to the coordinates for the specified coordinate system.
User-defined coordinate system
When working with CadnaA distinct combinations coordinate system-reference will be used repeatedly. To facilitate the selection user-defined coordinate systems can be saved. To this end, select - for example - the system „Swedish Transv. Mercator RT90 2.5gonV 0:-15“ with the reference point „RT90 (SE), Stockholm, Bessel“.
Click the button „Save“ and enter a name for the chosen combination.
Activate the option „Show user defined Coordinate Systems only“ on dialog „Coordinate System“. Subsequently, only those combination are listed on the list box „System“.
To delete user-defined coordinate systems select the respective system and click the button „Delete“. The specified system will be deleted without warning.