MRO HiRISE Digital Terrain Model (DTM)
DTM – Digital Terrain Model
Instrument:High Resolution Imaging Science Experiment
PDS Data Set ID: MRO-M-HIRISE-5-DTM-V1.0
For more information about HiRISE DTM products, see the HiRISE EDR RDR Volume SIS, Appendix D.
The High Resolution Imaging Science Experiment (HiRISE) Digital Terrain Models (DTMs) are a derived data product. A DTM is not an image, but a gridded (raster) product that records elevation values of a given terrain in each pixel. Corresponding metadata include map projection information so pixels can be associated with latitude and longitude. Values are either measured from the body center (i.e. radii), or relative to a given planetary geoid (i.e. elevation). DTM products are derived from a HiRISE stereo pair, where each observation has been taken of the same ground location, but from different viewing angles.
There are two types of products associated with the DTMs. The primary PDS image object is a DTM in a grid, or raster, format. Pixel values corresponded to elevations. Associated products are the orthoimages produced by orthorectifying each of the observations in the HiRISE stereo pair used to create the DTM. Orthographic rectification minimizes distortions in the image due to topography. Each orthographic image is in the same map projection as the corresponding DTM.
HiRISE DTM products have the following file names:
DTdps_xxxxxx_xxxx_yyyyyy_yyyy_inn.IMG
where:
d = type of data
E = areoid elevations
R = radii
p = projection (others are possible but these are the important ones)
E = Equirectangular
P = Polar Stereographic
s = grid spacing
A = 0.25 m
B = 0.5 m
C = 1.0 m
D = 2.0 m
E = 4.0 m
etc.
xxxxxx_xxxx = orbit number and target code from first source Product ID
yyyyyy_yyyy = orbit number and target code from second source Product ID
i = letter indicating producing institution
U = USGS
A = University of Arizona
P = Planetary Science Institute
nn = 2-digit version number
HiRISE Orthographic image products have the following file names:
ppp_xxxxxx_xxxx_ccc_s_nn_ORTHO.JP2 (with detached PDS label)
where:
ppp = mission phase
PSP = primary science phase
ESP = extended science phase
xxxxxx_xxxx = orbit number and target code from first source Product ID
ccc = color content
RED = visible RED, 1 band image
IRB = 3 band enhanced color (IR, RED, BG)
s = grid spacing (comparable to the DTM naming convention above)
A = 0.25 m
B = 0.5 m
C = 1.0 m
D = 2.0 m
etc.
nn = 2-digit sequence number starting with 01 (to distinguish images orthorectified to different DTMs)
In ODE, DTM products, with their associated orthographic images, have the following Product IDs:
DTDPS_XXXXXX_XXXX_YYYYYY_YYYY_INN