Supported Coordinate Systems

Exhaustive coordinate systems support is one of the advantages of PHOTOMOD software. PHOTOMOD software installation kit includes coordinate systems database set. This database set includes the so-called international database (it consists of coordinate systems for many countries) and also specialized databases for some countries. It is recommended to use specialized databases, if available, because they contain comprehensive icoordinate system information for each country. The databases distributed with PHOTOMOD contain more than 1000 coordinate systems. A user can define his own coordinate system using the built-in editor.

Types of coordinate systems:

Local Cartesian coordinate systems

These are arbitrary oriented local Cartesian orthogonal coordinate systems. PHOTOMOD software allows to set axis orientation (left or right-hand), axis labelling and unit. You can add your own units for linear, angular and indimensional variables. Your unit must be defined via the base unit of this variable type.

Local curved coordinate systems

Local curved coordinate systems differ from local Cartesian coordinate systems in Z-coordinate correction due to curvature of the Earth (R-radius sphere). The correction value depends on the selected space point X0,Y0 (automatically defined in base PHOTOMOD modules, manually defined in geodetic calculator). The coordinates converting from Cartesian to local coordinate systems executes by formula:

User can set sphere radius R, axis orientation (left or right-hand), axis labelling and unit.

Topocentric horizontal coordinate systems

In contrast to local curved coordinate systems topocentric horizontal coordinate systems location is uniquely determined in relation to base geodetic coordinate system. To define system user must set the origin (latitude, longitude and height) in base geodetic coordinate system. Z axis lies on ellipsoid surface normal in origin, one of the plane axis is oriented to the North, the other - to the East (concrete situation depens of the axis orientation (left or right-hand). User can set axis labelling and unit.

Geodetic coordinate systems

These are curvilinear coordinate systems. Point position is defined by means of geodetic latitude, longitude and height over ellipsoid. PHOTOMOD software allows to set datum, ellipsoid parameters (semi-major axis and semi-minor axis or back compression), converting parameters to global coordinate system (Molodensky or Bursa-Wolf transform), prime meridian longitude (if it is not Greenwich), plane coordinates and height units.

Geocentric (Cartesian) coordinate systems

These are coordinate systems with the origin in the mass center of the Earth ellipsoid. At that X axis is oriented to the intersection point of prime meridian and equator, Z axis to the North pole, and Y axis supplements coordinate system to right-hand triple. User can define prime meridian longitude, datum, axis labelling and unit.

Projected coordinate systems

These are coordinate system defined by the map projection. PHOTOMOD supports the following projected coordinate systems:

User can define parameters for all projections. User can set prime meridian longitude, datum or ellipsoid, coordinates labelling and units.

Standard PHOTOMOD delivery set includes special utility - GeoCalculator - geodetic calculator, designed to convert data from one coordinate system to another interactively or from text file.