GIF Underlay Regions
A GIF underlay is a full color picture used to fill the background between overlay lines and features.
Like solid underlays, this is visible only when there is thresholded radar data. Areas outside the radar coverage circle are displayed with a darkened version of the GIF underlay.
Do not mix GIF underlays and filled solid underlays.
| Statement | Description |
|---|---|
| UNDERLAY_CENTER lon lat | Selects the center location of an underlay file. |
| UNDERLAY_PROJECTION AED | Selects the projection of the underlay file. |
| UNDERLAY_REFERENCE lon lat | Selects the projection reference location. |
| UNDERLAY_STDPAR par1 par2 | Optional standard parallels. |
| UNDERLAY_ELLIPSOID rad 1/flat | Selects the equatorial radius (km) and flattening of the earth. 1/Flattening of 0 means circular. |
| UNDERLAY_SCALE x y | Selects the projection scale in km/pixel. |
| UNDERLAY_FILE file.gif | Selects the name of an underlay file. The file must reside in the ${IRIS_OVERLAY} directory. |
| AED | Azimuthal Equidistant |
| EDC | Equidistant Cylindrical |
| GAUSS | Gauss Conformal |
| GNOMONIC | Gnomonic |
| LAMBERT | Lambert Conformal Conic |
| MERCATOR | Mercator |
| POLSTEREO | Polar Stereographic |
| UTM | Universal Transverse Mercator |
| PERSPECTIVE | View from geosynchronous satellite |