MRO HiRISE Reduced Data Record with Embedded Map Projection (RDRV11)
RDRV11 – HiRISE Reduced Data Record with Embedded Map Projection
Instrument:High Resolution Imaging Science Experiment
PDS Data Set ID: MRO-M-HIRISE-3-RDR-V1.1
For more information about HiRISE RDR products, see the HiRISE RDR SIS.
The High Resolution Imaging Science Experiment (HiRISE) Reduced Data Record (RDR) products are radiometrically-corrected images resampled to a standard map projection. An RDR image is stored in the JPEG 2000 format, accompanied by a detached label providing supporting information about the observation. There will typically be two RDR standard products per HiRISE observation: a single-color RDR product built from the operating red-filter CCDs, and a three-color RDR product if the blue-green and near-infrared CCDs were additionally operating.
The radiometric correction corrects for instrument offset, dark current, and gain, then converts the image pixels to I/F reflectance. Geometric processing corrects for optical distortion and projects the image from spacecraft viewing to a map coordinate system. The Equirectangular map projection is employed for images observed in the latitude range -65 to 65 degrees. Images above 65 degrees to the poles use the Polar Stereographic projection.
The Equirectangular projection is based on the formula for a sphere. It is a simple projection providing a linear relationship between the geographic coordinates of latitude and longitude and the Cartesian space of the map. The RDR products mapped with the Equirectangular projection use different center latitudes of projection for every five-degree latitude bin from the equator to the 65 degrees latitude as shown in the table below. This choice of center latitudes reduces the total size of the dataset and reduces scale distortions. Note that the center latitude of the map projection is generally not the same as the center latitude of the observation.
|
Center latitude of projection for image centers falling in five-degree latitude bins |
|||
|---|---|---|---|
|
Latitude Range |
Center Latitude of Projection |
Latitude Range |
Center Latitude of Projection |
|
90 to 65 |
Polar Stereo. |
-90 to -65 |
Polar Stereo. |
|
70 to 65 |
65 |
-70 to -65 |
-65 |
|
65 to 60 |
60 |
-65 to -60 |
-60 |
|
60 to 55 |
55 |
-60 to -55 |
-55 |
|
55 to 50 |
50 |
-55 to -50 |
-50 |
|
50 to 45 |
45 |
-50 to -45 |
-45 |
|
45 to 40 |
40 |
-45 to -40 |
-40 |
|
40 to 35 |
35 |
-40 to -35 |
-35 |
|
35 to 30 |
30 |
-35 to -30 |
-30 |
|
30 to 25 |
25 |
-30 to -25 |
-25 |
|
25 to 20 |
20 |
-25 to -20 |
-20 |
|
20 to 15 |
15 |
-20 to -15 |
-15 |
|
15 to 10 |
10 |
-15 to -10 |
-10 |
|
10 to 5 |
5 |
-10 to -5 |
-5 |
|
5 to 0 |
0 |
-5 to 0 |
0 |
The Polar Stereographic projection is ideally suited for observations near the poles as shape and scale distortion are minimized. The RDR products mapped with the Polar Stereographic projection use the ellipsoid form of the equations. However, most cartographic processing software cannot support planetocentric coordinates for this projection with the ellipsoid equation. The fallback is to use the spherical equations. The error between the spherical and ellipsoidal equations is highest at 60 to -60 degrees latitude and is approximately 26 meters or about 100 HiRISE pixels. The error is less than the accuracy of the camera pointing, approximately 100 meters, and can be ignored.
HiRISE RDR aerobraking phase products have the following file names:
AEB_oooooo_tttt_ffff.JP2 (with detached PDS label)
where:
oooooo = observation sequence identifier
tttt = observation identification within the observation sequence
ffff = filter/CCD designation
RED = single-band image compiled from the red-filter images operating during the observation
COLOR = three-color image compiled from the overlapping blue-green, red, and near-infrared detectors
HiRISE RDR post-aerobraking products have the following file names:
ppp_oooooo_tttt_ffff.JP2 (with detached PDS label)
where:
ppp = mission phase
TRA = transition phase
PSP = primary science phase
ESP = extended science phase
oooooo = MRO orbit number
tttt = target code, refers to the latitudinal position of the center of the planned observation relative to the start of the orbit. The start of orbit is located at the equator on the descending side (night side) of the orbit. A target code of 0000 refers to the start of orbit. The target code increases in value along the orbit track ranging from 0000 to 3595. This convention allows the file name ordering to be time sequential. The first three digits refers to the number of whole degrees from the start of orbit, the fourth digit refers to the fractional degrees rounded to the nearest 0.5 degrees. Values greater than 3595 identify observations as off-Mars or special operations.
Examples:
0000 = equator, descending side of orbit
0900 = south pole
1800 = equator, ascending side
2700 = north pole
Off-Mars and Special Values:
9000 = star observation
9010 = Phobos observation
4002 = Deimos observation
4003 = Special calibration observation
ffff = filter/CCD designation
RED = single-band image compiled from the red-filter images operating during the observation
COLOR = three-color image compiled from the overlapping blue-green, red, and near-infrared detectors
In ODE, HiRISE RDR products have the following Product IDs:
PPP_OOOOOO_TTTT_FFFF