#  Metadata

Of prime importance for any spacecraft instrumentation is the knowledge of
time, location and orientation of the spacecraft and target. This is provided
for recent NASA and ESA datasets through the SPICE  2  software standards from
NASA's Navigation and Ancillary Information Facility (NAIF). For each
instrument observation, such information is available as a 'kernel' that can
be read by freely available tools. Most instrument teams write their own
software to use the relevant sub-set of information from the SPICE system. The
most recent version of the SPICE toolkit is version N65, released July 23rd
2014. New releases occur every two to three years. It is expected that the
next SPICE release will remove an existing limit to the size of DSK formatted
datasets (4 million facets). SPICE was developed in part explicitly to improve
archiving of datasets from planetary science missions. Although the use of
SPICE is not a requirement of the NASA Planetary Data System, it is
recommended by the International Planetary Data Alliance  3  .

The MiARD project has required some programming effort (by DLR) in order to
correctly read and interpret the Rosetta mission spice kernels for use with
the shape model, and check the correctness of this code. We also had to
develop our own more precise SPICE kernels as part of the production of the
shape model (see D1.4)

#  Project dataset naming conventions

Because the project is using public data from many sources for a variety of
purposes, and aims to archive public data of different types, we do not expect
to be able to consistently use a 'project' nomenclature. Care will be taken to
ensure that version numbers, release dates and change logs (or dataset
descriptions) are used. Archives such as ESA's PSA have additional
documentation requirements.

#  Quality control/review

The NASA/ESA shared archives have an internal quality review process which
must be satisfied before data is made available in the archive. For datasets
from the MiARD project supporting peer-reviewed publications, the quality
review is the peer review process of the journal.

Datasets from the project

#  Shape models and associated data

Shape models of comet 67P are a precursor for much of the work within the
MiARD project - e.g. mapping of physical properties and modelling of activity.

##  Terminology

The series of shape models obtained by the OSIRIS instrument team are released
with a designation SHAPn where n denotes the time period of the observations
made by the OSIRIS camera which were used for the shape reconstruction. There
are plans for pre- and -postperihelion shape models which will use data from
more than one OSIRIS time period (SHAP1-SHAP6 for pre-perihelion and
SHAP7-SHAP8 for the post-perihelion model). As of August 2016, the SHAP5 SPC
model has been delivered to NASA's PDS/SBN to begin the review process prior
to archiving and publication. The SHAP7 SPC model is currently expected to be
ready for submission by the end of 2016. The 'final' shape models, SHAP8,
SHAP5PRE and SHAP8POST are expected to be ready no earlier than April 2017,
and will have a sampling of about 6m. We have maintained the use of this SHAPn
convention to indicate the time period from which a shape model is derived.

In addition to the global shape models, a series of local, higher resolution,
digital terrain models (DTM's) are planned by the project.

SPC and SPG are two different mathematical approaches to deriving depth
information from pairs of images. The MiARD project seeks to combine the
strengths of both approaches (roughly speaking, SPG gives more accurate
results for rough areas with steep slopes, SPC for smooth plains) to produce
minimum-error shape models of the comet.

Further terminology and file formats relevant to the shape models are defined
in the PSA document USER-GUIDE.ASC in the RO-C-MULTI-5-67P-SHAPE-V1.0
directory.

##  Source data

OSIRIS camera images are processed by the OSIRIS PI's (with the help of SPICE
kernels) to produce a shape model. These shape models will be archived in the
PDS/PSA after a review process by the archive service, but the MiARD project
has access to them (through the PI's) beforehand. Text taken from ESA's PSA
archive:

##  _**Shape Dataset Organization** _

_This shape-model dataset includes a wide variety of shape models of comet
67P/Churyumov-Gerasimenko. They have been developed by several different
groups, using data from several different portions of the Rosetta mission,
using a variety of techniques, and intended for a variety of different
purposes. Several of these models have been cited in the literature as
underlying various investigations. The different shape models are collected
together in order to make it easier for users to choose the appropriate model,
but the wide variety means that there are many possible ways to organize the
archive._

_At the time this document is written (February 2016), only a few of the
anticipated models have been archived (and some models have not yet even been
created), but to understand the organization we discuss generically all the
models that we hope will be archived. All the shape models tesselate the
surface of the nucleus into triangular, flat plates. At the highest level, the
datasets are separated into ascii formats and binary formats. The binary
formats are exclusively the Digital Shape Kernels that are used in SPICE
(routines currently in beta-test version but expected to be in the general
release in spring 2016). The ascii versions are designed for non-SPICE users
and for simple visualization of the geometry. They always include an ascii
version that follows the standard used in PDS-SBN for decades (long prior to
the availability of DSK) that includes a wrapper that makes them viewable in
any VRML-aware application, of which there are many available._

_At the next level, the models are divided into groups corresponding to the
team that produced the models and the method that team used. The four groups
at this level are, as abbreviated in directory names and file names: 1)
mspcd_lam, Modified StereoPhotoClinometry by Distortion, produced at the
Laboratoire d’Astrophysique de Marseille, 2) spc_esa, StereoPhotoClinometry
produced by the flight operations team of ESA (European Space Agency) and
converted to standard formats by the Rosetta Mission Operations Center (RMOC),
3) spc_lam_psi, StereoPhotoClinometry produce by a collaboration between the
Laboratoire d’Astrophysique de Marseille and the Planetary Science Institute,
and 4) spg_dlr, StereoPhotoGranulometry produced at the German Aerospace
Center (DLR) group in Berlin. This grouping also separates the models by the
instruments used to obtain the input images, the models from ESA having been
derived entirely from the NAVCAMs (NAVCAM1 and NAVCAM2 are nominally
identical), whereas the other three groups are based entirely on the
scientific cameras, OSIRIS-NAC and OSIRIS-WAC. At this writing, there are
currently no models available in group 4. See other documents to understand
the differences among the techniques_

_At the third level, the models are sorted by the time period of the data
used, which affects the geographic coverage of the data and the best spatial
resolution achieved. For the models from ESA, this is denoted by the last MTP
(Medium Term Planning) cycle of the data, whereas for the models using the
scientific cameras, the OSIRIS teams used sequential numbers to indicate the
time period, with details given in the relevant subdirectories. At this
writing, the ESA models utilize data obtained through MTP09 (through mid-
November 2014, i.e., data prior to the release of the Philae Lander)._

_The OSIRIS models currently on hand are all SHAP2, using data only through 3
August 2014. Anticipated future deliveries include an SPG version of SHAP4,
SPC and MSPCD versions of SHAP5, and TBD versions of SHAP7 (data being taken
as this is written). At the next level, because the full-resolution models are
very large, there are models with various levels of reduced resolution
available, intended for purposes that do not require the highest resolution
and therefore speed up calculations._

###  Relevant formats and required software

Shape models from the project will be made available in a format compatible
with the SPICE toolkit in so far as this is possible i.e. using TRIPLATE/VRML
and SPICE/DSK. (However, the DSK format is currently incompatible with the
full resolution models from the project (four million facet limit), although
changes are planned by NASA's NAIF). In any case, data formats will be
consistent with the NASA/ESA archive policy.

###  Archiving/distribution policy

The shape models and several of the GIS datasets from MiARD will be made
publicly available through ESA's PSA after an initial peer-reviewed
publication describing them, and after passing the archives' review procedures
(expected to last about six months). For some of the data products from the
project, the open access journal used provides its own archive (e.g. the
geomorphological regions described in deliverable D1.6 were published in
Planetary & Space Sciences which uses the Mendeley Data repository).

Other datasets, for which the demand is less or the need for reviewing not
apparent will be made available through the project's website.

**Table 2 Summary of datasets for shape models**  
  
<table>  
<tr>  
<th>

**Datasets required for input**

</th>  
<th>

**New datasets and names**

</th>  
<th>

**Format(s) and standards**

</th>  
<th>

**Archiving**

</th> </tr>  
<tr>  
<td>

_SHAPn_ models from OSIRIS instrument team.

</td>  
<td>

Global shape model CG- DLR_SPG-SHAP7-V1.0

</td>  
<td>

.PLY and .PNG

</td>  
<td>

In review at ESA PSA. See D1.8. Available on request through project website
or Europlanets website

</td> </tr>  
<tr>  
<td>

_"_

</td>  
<td>

Global shape model

(SPG+MSPCD) with 12, 20 or

44 million facets, and 103 local

DTM's used

</td>  
<td>

.PLY, Geotiff, binary

FITS

</td>  
<td>

Project website.

</td> </tr>  
<tr>  
<td>

_"_

</td>  
<td>

Local digital terrain models and elevation models (plus quality maps, artefact
maps and orientation information)

</td>  
<td>

</td>  
<td>

To be submitted to PSA after peer reviewed publication of methodology. See
table below for names of DTM areas.

</td> </tr>  
<tr>  
<td>

_"_

</td>  
<td>

Improved SPICE kernels _cg-dlr_spg-shap7-v1.0.bc cg-dlr_spg-shap7-v1.0.bsp_

</td>  
<td>

SPICE format:

CK kernels

SPK kernels

</td>  
<td>

</td> </tr> </table>  
<table>  
<tr>  
<th>

**#**

</th>  
<th>

**DTM Name**

</th>  
<th>

**Time Range**

</th>  
<th>

**Surface (m²)**

</th>  
<th>

**#Facets**

</th>  
<th>

**Sampling (cm)**

</th>  
<th>

**Quality**

</th> </tr>  
<tr>  
<td>

1a

</td>  
<td>

Agilkia

</td>  
<td>

Beginning to Philae landing

</td>  
<td>

94,710

</td>  
<td>

871,680

</td>  
<td>

33

</td>  
<td>

Medium, linear

artifacts

</td> </tr>  
<tr>  
<td>

1b

</td>  
<td>

</td>  
<td>

Philae landing to end

</td>  
<td>

36,477

</td>  
<td>

332,032

</td>  
<td>

33

</td>  
<td>

Good

</td> </tr>  
<tr>  
<td>

2

</td>  
<td>

Ash_aeolian

</td>  
<td>

Beginning to perihelion-2m*

</td>  
<td>

80,559

</td>  
<td>

191,936

</td>  
<td>

65

</td>  
<td>

Very good

</td> </tr>  
<tr>  
<td>

3a

</td>  
<td>

Hapi_dunes

</td>  
<td>

Beginning to perihelion-2m*

</td>  
<td>

86,196

</td>  
<td>

117,360

</td>  
<td>

86

</td>  
<td>

Very good

</td> </tr>  
<tr>  
<td>

3b

</td>  
<td>

</td>  
<td>

Perihelion+2m* to end

</td>  
<td>

86,226

</td>  
<td>

469,440

</td>  
<td>

43

</td>  
<td>

Very good

</td> </tr>  
<tr>  
<td>

4

</td>  
<td>

Anubis_polygones

</td>  
<td>

Beginning to end

</td>  
<td>

9166

</td>  
<td>

57,344

</td>  
<td>

40

</td>  
<td>

Good

</td> </tr>  
<tr>  
<td>

5

</td>  
<td>

Geb_fractures

</td>  
<td>

Beginning to perihelion-2m*

</td>  
<td>

84,709

</td>  
<td>

305,728

</td>  
<td>

53

</td>  
<td>

Medium, linear

artifacts

</td> </tr>  
<tr>  
<td>

6

</td>  
<td>

Ash_crater

</td>  
<td>

Beginning to perihelion-4m*

</td>  
<td>

62,507

</td>  
<td>

151,872

</td>  
<td>

64

</td>  
<td>

Good, some artifacts

</td> </tr>  
<tr>  
<td>

7a

</td>  
<td>

Maat_pits

</td>  
<td>

Beginning to perihelion-2m*

</td>  
<td>

30,794

</td>  
<td>

150,784

</td>  
<td>

45

</td>  
<td>

Medium, some artifacts

</td> </tr>  
<tr>  
<td>

7b

</td>  
<td>

</td>  
<td>

Perihelion+3m* to end

</td>  
<td>

29,344

</td>  
<td>

150,784

</td>  
<td>

44

</td>  
<td>

Good

</td> </tr>  
<tr>  
<td>

8

</td>  
<td>

Bes_fractures

</td>  
<td>

Perihelion+4m* to end

</td>  
<td>

34,966

</td>  
<td>

91,392

</td>  
<td>

62

</td>  
<td>

Good

</td> </tr>  
<tr>  
<td>

9a

</td>  
<td>

Anubis_depression

</td>  
<td>

Beginning to perihelion-4m*

</td>  
<td>

109,062

</td>  
<td>

511,104

</td>  
<td>

46

</td>  
<td>

Very good

</td> </tr>  
<tr>  
<td>

9b

</td>  
<td>

</td>  
<td>

Perihelion+4m* to end

</td>  
<td>

110,897

</td>  
<td>

511,104

</td>  
<td>

47

</td>  
<td>

Very good

</td> </tr>  
<tr>  
<td>

10a

</td>  
<td>

Nut_wind_tails

</td>  
<td>

Beginning to perihelion-2m*

</td>  
<td>

74,776

</td>  
<td>

163,584

</td>  
<td>

68

</td>  
<td>

Very good

</td> </tr>  
<tr>  
<td>

10b

</td>  
<td>

</td>  
<td>

Perihelion+2m* to end

</td>  
<td>

66,648

</td>  
<td>

205,248

</td>  
<td>

57

</td>  
<td>

Good, some artifacts

</td> </tr> </table>

**Table 3 Parameters of the fifteen local DTMs included in deliverable D1.2.**

#  GIS data-sets

A number of the datasets from the MiARD project are compatible with
'Geographical

Information Systems' because they combine vector or scalar data with a
coordinate grid

(usually the CHEOPS ** Error! Bookmark not defined.  ** reference system
adopted for 67P/Churyumov-

Gerasimenko). Some of the project's datasets such as the local Digital Terrain
Models (DTMs) use the GeoTiff format associated with popular GIS software
packages such as ArcGIS and QGIS.

##  Gravity  
  
<table>  
<tr>  
<th>

**Datasets required for input**

</th>  
<th>

**New datasets and names**

</th>  
<th>

**Format(s) and standards**

</th>  
<th>

**Archiving**

</th> </tr>  
<tr>  
<td>

Shape models

from

project, assumption s about density

</td>  
<td>

shape_<parameter>.ply, shape_<parameter>_colorbar.svg

<map_projection>/<parameter>_<projection_info>_ms<height ><fr>.<ext>

</td>  
<td>

.ply,.svg

.img, .png or

.svg

</td>  
<td>

Project website

"

</td> </tr> </table>

**Table 4 Datasets for gravity maps (part of D1.3). The _parameters_ included
are _potential_ (gravitational potential), _dynamical_height_ , _gc_ (surface
acceleration), _slope_gc_ (local terrain slope relative to local gravitational
field, including centrifugal force). _Map projection_ is one of equidistant
cylindrical coordinates, or a north/south polar view Lambert azimuthal equal
area projection; _height_ is the height in pixels of the map; _fr_ is the
coordinate frame used, one of Cheops, SL, BL or NR ** Error! Bookmark not
defined. **.. Full documentation of the file format is given in the D1.3
report.**

##  Albedo  
  
<table>  
<tr>  
<th>

**Datasets required for input**

</th>  
<th>

**New datasets and names**

</th>  
<th>

**Format(s) and standards**

</th>  
<th>

**Archiving and preservation**

</th> </tr>  
<tr>  
<td>

OSIRIS-WAC images

close to zero phase

</td>  
<td>

3D models maps

</td>  
<td>

.ply, .svg

.img, .pmg, .svg

</td>  
<td>

Project website

"

</td> </tr> </table>

**Table 5 Same dataset naming scheme as for the gravity maps, see also D1.3**

##  Temperatures

**Table 6 Summary of temperature datasets, see D4.5**  
  
<table>  
<tr>  
<th>

**Datasets required for input**

</th>  
<th>

**New**

**datasets and names**

</th>  
<th>

**Format(s) and standards**

</th>  
<th>

**Archiving and preservation**

</th>  
<th>

**Comments**

</th> </tr> </table>  
<table>  
<tr>  
<th>

VIRTIS (from Cédric

Leyrat)

MIRO sub-mm (MPS)

MIRO mm (MPS)

</th>  
<th>

MIRO

temperature maps.

</th>  
<th>

•

•

•

•

•

•

</th>  
<th>

MIRO_README: a file

explaining the contents of the data and how they have been created.

MIRO_DATA: a directory containing the data files (ASCII tables). The data is
the brightness temperature in the mm and sub-mm channels. The data were binned
according to the LST (Local Solar Time) of their acquisition, with a step of
1/24  th  of the rotation. So, there are 24 VTK files for each data set (sub-
mm and mm channels). For each LST bin, there is only one temperature per facet
of the shape model,

i.e. we averaged temperatures whenever necessary.

MIRO_VTK_MM: a directory

containing the brightness temperature in the mm channel, projected onto the 3D
shape model (VTK format)

MIRO_VTK_SUBMM: a

directory containing the brightness temperature in the sub-mm channel,
projected onto the 3D shape model (VTK format)

MIRO_PNG: a directory containing an example of the data projected onto the
shape model (PNG image format)

MIRO_temp_read.py: a Python routine to view the data onto the 3D shape model

(Python language format)

</th>  
<th>

Project website

</th>  
<th>

"VIRTIS-H calibration is still a preliminary, unchecked calibration, with
known

inconsistencies". See also

PSA document VIRTISH_CALIBRATION.PDF, issue 1.4 23rd July 2008.

</th> </tr>  
<tr>  
<td>

</td>  
<td>

VIRTIS

radiance maps

</td>  
<td>

•

</td>  
<td>

VIRTIS_README: a file

explaining the contents of the data and how they have been created.

</td>  
<td>

</td>  
<td>

</td> </tr>  
<tr>  
<td>

</td>  
<td>

</td>  
<td>

•

</td>  
<td>

VIRTIS_DATA: a directory containing the data files (ASCII tables). The data is
the radiance at 4.0 μm, 4.5 μm, 4.75 μm and 4.95 μm.

</td>  
<td>

</td>  
<td>

</td> </tr>  
<tr>  
<td>

</td>  
<td>

</td>  
<td>

•

</td>  
<td>

VIRTIS_VTK: a directory containing the radiance,

</td>  
<td>

</td>  
<td>

</td> </tr>  
<tr>  
<td>

</td>  
<td>

</td>  
<td>

projected onto the 3D shape model (VTK format)

  * VIRTIS_PNG: a directory containing images of the 

  

VIRTIS data (PNG image format)

  * VIRTIS_AVI: a directory containing a movie of the VIRTIS data projected onto the 3D shape model (AVI movie format) 

  

  * 00368190214_M1.vtu: the 

  

reference file used to create the VTK files (VTU format)

VIRTIS_facet_data_to_vtu1.pro: the IDL routine used to create the VTK files
(IDL language format)

</td>  
<td>

</td>  
<td>

</td> </tr> </table>

##  Activity maps and models (3D Gas and dust distribution)

**Table 7 Activity datasets, see D2.5**  
  
<table>  
<tr>  
<th>

**Datasets required for input**

</th>  
<th>

**New datasets and names**

</th>  
<th>

**Format(s) and standards**

</th>  
<th>

**Archiving and preservation**

</th> </tr>  
<tr>  
<td>

Shape model and outgassing code and parameters

</td>  
<td>

There are eight files in total (plus a readme.txt), these are: for each model
(inhomogeneous or purely insolation driven) there is one file for the gas
number density and velocity, and one file for each dust particle size. The
filenames are self-explanatory: _inhomogeneous_dust_1.6um.txt
inhomogeneous_dust_16um.txt inhomogeneous_dust_160um.txt inhomogeneous_gas.txt
insolationDriven_dust_1.6um.txt insolationDriven_dust_16um.txt
insolationDriven_dust_160um.txt insolationDriven_gas.txt_

</td>  
<td>

ASCII space separated columns. The seven columns (x, y, z, number density, u,
v, w) are:

  * x,y,z spatial coordinates in metres from centre of comet (Cheops reference frame) 

  

  * the number density of the gas or dust (m  -3  ) 

  

  * u, v, w the x,y,z components of the velocity vector (m/s) 

  

</td>  
<td>

Project website

</td> </tr> </table>

##  Maps of regional properties

**Table 8 Defined geological units (D1.6) dataset**  
  
<table>  
<tr>  
<th>

**Datasets required for input**

</th>  
<th>

**New datasets and names**

</th>  
<th>

**Format(s) and standards**

</th>  
<th>

**Archiving and preservation**

</th>  
<th>

**Comments**

</th> </tr>  
<tr>  
<td>

Shape models from project

</td>  
<td>

cg-dlr_spg-shap7v1.0_125Kfacets_region s.vtk

cg-dlr_spg-shap7v1.0_125Kfacets_subreg

ions.vtk

</td>  
<td>

.vtk

</td>  
<td>

Mendeley Data,

https://data.mendeley.com/datasets/ 2845znt54k/1

A more complete set of resolutions

(larger files) is in review with the

ESA PSA

</td>  
<td>

CC BY

4.0 licence

</td> </tr> </table>

Glossary and abbreviations

ESA European Space Agency

ESCO European Space Operations Center

GIS Geographic Information System

MSPCD Multi-resolution Stereophotoclinometry by Deformation

NASA USA National Air and Space Administration

NAVCAM navigational cameras on Rosetta mission

OSIRIS a camera instrument on Rosetta mission

PDS NASA's Planetary Data System _http://pds-smallbodies.astro.umd.edu_

PSA ESA's Planetary Science Archive
_http://www.cosmos.esa.int/web/psa/psaintroduction_

PI Principal Investigator. Term used by ESA or NASA to denote the individual
responsible for an instrument and its data

RSOC Data repository run by the Rosetta Science Ground Segment

SPICE name of system that provides spacecraft orientation and position, or
time of dataset. ESA maintains a repository of SPICE kernels for the Rosetta
mission _http://www.cosmos.esa.int/web/spice/spice-for-juice ._ SPICE= **S**
pacecraft, **P** lanet, **I** nstrument, **C** amera-matrix, **E** vents.

SPG stereo photogrammetry

SPC stereo photoclinometry

SHAPn denotes time period over which images were collected, used for numerical
descriptions of the shape of comet 67P

VIRTIS an infrared instrument on the Rosetta mission