Appendix
1. Planetary Texture
a) Specifications
"flow_ig" supports the following specifications as a texture image:
Image Format |
FITS, PNG, JPEG |
Size |
The number of vertical and horizontal pixels must be a power of 2. |
The others |
FITS is the origin at the bottom left of the image according to the SAOImage DS9. However, if you specify the -f option is "flow_ig" top left will be the origin. |
∗ Ring texture images of planets are not drawn correctly If you do not specify a transparent PNG.
b) Recommendations
We recommend the following specification to prepare a global planetary surface texture:
- Set the aspect ratio in pixel width and height to 2:1, such as 1024 x 512, 2048 x 1024 etc.
- Use equidistant cylindrical projection (simple cylindrical projection)
- Set the longitude from 0 degree at the left edge to +360 degrees at the right edge
- Set the latitude from -90 degrees at the bottom to +90 degrees at the top
A grid-line example image is here:
grid Line
2. Coodinate System of the Shape Model
Coordinate system of a shape model is as follows:
|
|
+Z |
Arctic Direction. |
+X |
Meridional direction. |
+Y |
Direction to complement the right-handed coordinate system |
3. WMS cached database
If you specify WMS servers to retrieve textures, "flow_ig" creates a cached database:
~/.flow/wms_cache.edb
The cached database is used to keep from duplicate retrieving for the same request to WMS servers.
If you run the flow_ig with the -x option (wms_delete_cache), the cache will be deleted upon launching.