Several different coordinate systems are presented to the VAPOR GUI user:
- User coordinates are the 3D + time world coordinates of the user's model output. These could be in meters and seconds, or any other units. The Region, 2D, Image, Probe, Contour, and Flow panels present the box coordinates in user coordinates. Time is usually displayed in time steps (which can be any size) but can be shown as a time stamp for some models (e.g. WRF). Note that for WRF models the horizontal user coordinates correspond to position in projection space and are in meters. For ocean models (and other models that use a lat/lon projection) the horizontal user coordinates are based on distance at the equator and do not take into account the reduced distance between points at the same latitude near the poles.
- Grid coordinates are the integer array coordinates that are used to access variable data. These are also shown in the Region, 2D, Image, Probe and Flow panels. These are not adjusted based on the refinement level being visualized.
- VAPOR will also display latitude and longitude coordinates if the VDC includes a map projection. The Probe, 2D, and Image panels display extents in lat/lon coordinates, and also will display the coordinates of cursor-selected points in lat/lon when the rendering is enabled in these panels.
- Coordinate axis annotation (enabled in the visualizer features panel) indicates the x,y,and z-coordinates in user coordinates. The horizontal axes for most geo-referenced data can also be displayed using latitude and longitude coordinates, by checking "Annotate with Lat/Lon"
