Landmark File Format
The Landmark File data format is a comma-separated format with a required header followed by data records. A version indictor is also required as the first uncommented line of the file. Version 1.0 is the only supported version. Comment lines can occur anywhere in the file and are identified by placing # as the first character in the line. Fields can occur in any order.
The header record is required and specifies the field names in comma-separated format. ODTK ignores field names not included in the table below. Specification of either a textual or integer identifier is recommended, though not required. If you provide neither, ODTK will create integer IDs for each landmark in sequential, increasing order starting with 1 for the first data record in the file.
The following table delineates the Landmark file header field names and their descriptions, and includes whether or not each field is required.
| Field Name | Description | Required? |
|---|---|---|
| ID | Textual identifier | N |
| IDINT | Integer identifier; value>0 | N |
| Latitude | Northerly latitude specified in degrees; -90 <= Value <= 90.0 | Y* |
| Longitude | Easterly longitude specified in degrees; -180 <= Value <= 360.0 | Y* |
| Altitude | Altitude above reference surface, in kilometers | N |
| X | X component of position in body-fixed reference frame, in kilometers | Y* |
| Y | Y component of position in body-fixed reference frame, in kilometers | Y* |
| Z | Z component of position in body-fixed reference frame, in kilometers | Y* |
| Diameter | Diameter of landmark, in kilometers | N** |
| Radius | Radius of landmark, in kilometers | N** |
| Latitude_SD | Uncertainty in latitude specified in degrees; value > 0 | N*** |
| Longitude_SD | Uncertainty in longitude specified in degrees; value > 0 | N*** |
| Altitude_SD | Uncertainty in altitude, in kilometers; value > 0 | N*** |
| X_SD | Uncertainty in X component of position, in kilometers; value > 0 | N*** |
| Y_SD | Uncertainty in Y component of position, in kilometers; value > 0 | N*** |
| Z_SD | Uncertainty in Z component of position, in kilometers; value > 0 | N*** |
* You must specify position information in either Cartesian or Lat/Long/Alt coordinates. If you choose Lat/Long/Alt coordinates, Alt is optional and will default to zero if you don’t specify it.
** If you supply size information, ODTK will use it in the computation of the image processing bias.
*** If you supply position uncertainty information, ODTK will use it in the deweighting of measurements during estimation.
Here is an example of a Landmark file:
version 1.0 #Sample lunar crater data #Data reference: Robbins, S.J., (2018), https://dx.doi.org/10.1029/2018JE005592. ID,Latitude,Longitude,Diameter,Latitude_SD,Longitude_SD 00-1-000000,-19.8304,264.757,940.96,0.00788792,0.00842373 00-1-000001,44.7763,328.602,249.84,0.0111776,0.0151013 00-1-000002,57.0866,82.0995,599.778,0.0084645,0.0195153 00-1-000003,1.96124,230.622,558.762,0.00707867,0.00783918 00-1-000004,-49.1496,266.347,654.332,0.00882679,0.0177327 00-1-000005,-35.6024,208.486,505.312,0.00929176,0.010565 …