toast_pixel_for_point¶
- toasty.toast.toast_pixel_for_point(depth, lat, lon, coordsys=ToastCoordinateSystem.ASTRONOMICAL)[source]¶
Identify the pixel within a TOAST tile at a given depth that contains the given point.
- Parameters:
- depthnon-negative integer
The TOAST tile pyramid depth to drill down to. For any given depth, there exists a tile containing the input point. As the depth gets larger, the precision of the location gets more precise.
- latnumber
The latitude (declination) of the point, in radians.
- lonnumber
The longitude (RA) of the point, in radians. This value must have already been normalized to lie within the range [0, 2pi] (inclusive on both ends.)
- coordsysoptional
ToastCoordinateSystem
The TOAST coordinate system to use. Default is
ToastCoordinateSystem.ASTRONOMICAL
.
- Returns:
- A tuple
(tile, x, y)
. The tile is theTile
at the given depth - that best contains the specified point. The x and y values are
- floating-point numbers giving the pixel location within the 256×256 tile.
- The returned values are derived from a quadratic fit to the TOAST
- coordinates of the pixels nearest the specified coordinates lat and lon.
- A tuple