## Introduction 

-----

In order to access and view the geometry for an ISIS image cube \[raw
instrument camera cube, (i.e., PDS-EDR)\], the application
[**spiceinit**](http://isis.astrogeology.usgs.gov/Application/presentation/Tabbed/spiceinit/spiceinit.html)
must be **successfully** applied to the cube. Once **spiceinit** has
been applied, there are a number of applications that will be able to
compute and output statistics about your image based on the raw **Camera
Geometry** .


## Camera Geometry 

-----

**Camera Geometry** refers to the viewing geometry of an observation. It
also implies a 'non-projected' cube (sometimes referred to as a Level1,
though it does not require radiometric calibration). 

!!! Note "Within the ISIS environment, unless otherwise specified, **ALL** applications default (for input and output) to the following geometric reference (regardless of target body):"

      - **Longitude Domain = 360** Longitudes will be reported in the
        range of 0 to 360 degrees (not -180 to 180)
      - **Latitude System = Ocentric** Versus Ographic; Note: there is
        not difference for a spherical body
      - **Longitude Direction = East** Longitude values increase to the
        east

Definitions for the geometric reference terms can be found in [Learning About Map Projections](../Camera%20Geometry%20and%20Projections/Learning%20About%20Map%20Projections.md)


## Camera Information Applications 

-----


### **Camstats** 

For a given image cube, the application
[**camstats**](http://isis.astrogeology.usgs.gov/Application/presentation/Tabbed/camstats/camstats.html)
will report Minimum, Maximum, Average and Standard Deviation for the
following:

**Geometric Information**

  - Latitude
  - Longitude
  - Resolution, LineResolution, SampleResolution
  - AspectRatio

**Photometric Information**

  - Phase Angle
  - Emission Angle
  - Incidence Angle
  - LocalSolarTime
  - NorthAzimuth

Example (not all parameters shown):

    camstats from=xxxx.cub linc=1 sinc=1

!!! Note " The *linc* and *sinc* parameters default to 1. For larger pixel size images, such as HiRISE or CTX data, setting the *linc* and *sinc* values to higher values (10, 100) would help the application to run faster. Set with care knowing that the application is literally skipping line/sample data to retrieve SPICE information."

  - **camstats** supplies useful information that can be considered and
    applied when map projecting images (Level2 processing).


### **Mosrange** 

Given a list of multiple raw image cubes, the application
[**mosrange**](http://isis.astrogeology.usgs.gov/Application/presentation/Tabbed/mosrange/mosrange.html)
computes the range of latitude/longitude and resolution statistics for
all images given.

Example (not all parameters shown):

    mosrange fromlist=list_of_lev0_w_spice.lis to=output_map_information.map projection=Equirectangular

  - This is one application that allows the user to specify output
    latitude type, longitude direction and longitude domain.

  - Knowing the information about your set of images at this point is
    useful, especially if the goal is to generate a mosaic. The output
    can be used later in defining the desired output map projection in
    Level 2 processing.


### **Campt** 

The application
[**campt**](http://isis.astrogeology.usgs.gov/Application/presentation/Tabbed/campt/campt.html)
will supply geometric and photometric information based on a *single*
latitude/longitude value (remember the raw camera geometry defaults when
entering values) or a *single* line/sample coordinate of an image cube.

**Geometric Information**

  - Latitude
  - Longitude
  - Resolution

**Photometric Information**

  - Phase Angle
  - Emission Angle
  - Incidence Angle

**In addition** , this application will return a list of other
spacecraft, sun and instrument related information such as:

  - SpacecraftPosition
  - SpacecraftAzimuth
  - SubSpacecraftLongitude
  - SubSolarLatitude
  - SubSolarLongitude
  - Time information (EphemerisTime, UTC)

Example (not all parameters shown):  

    campt from=xxxx.cub latitude=0.0 longitude=270.0 type=ground

or

Example (not all parameters shown):  
*Enter line/sample pixel location-current default of application*

    campt from=xxxx.cub line=512 sample=512 type=image


### **Phocube** 

[**phocube**](http://isis.astrogeology.usgs.gov/Application/presentation/Tabbed/phocube/phocube.html)
will compute and generate a separate output [multi-band ISIS
cube](https://DOI-USGS.github.io/ISIS3/gh-pages/ISIS_Cube_Format.html) where each band will represent the selected
(parameter=TRUE) geometric and photometric elements. The bands are named
appropriately in the output cube labels: **Group=BandBin** .

``` 
 Object = IsisCube
     Object = Core
     StartByte   = 65537
     Format      = Tile
     TileSamples = 128
     TileLines   = 128
     Group = Dimensions
       Samples = 1024
       Lines   = 1024
       Bands   = 6
     End_Group
     Group = Pixels
       Type       = Real
       ByteOrder  = Lsb
       Base       = 0.0
       Multiplier = 1.0
     End_Group
   End_Object
    Group = BandBin
    Name = ("Phase Angle", "Emission Angle", "Incidence Angle", "Latitude", "Longitude")
  End_Group
```

  - **phocube** requires a successful **spiceinit** execution
  - **phocube** can be applied to an unprojected "Level1" image cube or
    an individual map projected "Level2" image.
  - **phocube** will not work on a mosaic cube, the photometric
    information for each input file is eliminated from the mosaic output
    file.

Example:  
Run **phocube** on a fly-by Cassini ISS-Wide Angle Camera image of
Enceladus. In this example, **phocube** will generate a 6-band output
cube.

@TODO
!!! Note "The image used in this example has been processed through Level1 \[ingestion, spiceinit and radiometric calibration\]. Refer to: [Working with Cassini ISS Data](Camera%20Geometry.md)"

Each band will contain the information asked for (parameters set to
true) in the following command:

    phocube from=W1487302209_2.lev1.cub to=W1487302209_2_pho.cub 
            phase=true  emission=true  incidence=true  latitude=true  longitude=true 

  - All bands of the phocube output can be displayed in qview
  - To access a selected band in an application, use the cube-attribute
    syntax.  

For example, calculate and report the average values of the Incidence
Angle (Band 3).  
The command line for the **stats** applications is as follows:

    stats from=W1487302209_2_pho.cub+3  to=W1487302209_2_inc_stats.pvl 

The Example ISS Wide-Angle Camera image of Enceladus and the output of
**phocube** :


<figure class="inline" markdown>
  ![Cassini ISS WA-camera Enceladus](../../assets/camera_geometry/Iss_WAC_enceladus_sm2.png){: style="width:225px;height:225px"}
  <figcaption>Enceladus</figcaption>
</figure>

<figure class="inline" markdown>
  ![Iss\_WAC\_ema\_figure](../../assets/camera_geometry/Iss_WAC_ema_figure.png "Phocube-Emission Angle Band"){: style="width:225px;height:225px"}
  <figcaption>Phocube: Emission Angle Band</figcaption>
</figure>

<figure markdown>
  ![Iss\_WAC\_inc\_figure](../../assets/camera_geometry/Iss_WAC_inc_figure.png "Phocube Incidence Angle Band"){: style="width:225px;height:225px"}
  <figcaption>Phocube: Incidence Angle Band</figcaption>
</figure>


<figure class="inline" markdown>
  ![Iss\_WAC\_phase\_figure](../..//assets/camera_geometry/Iss_WAC_phase_figure.png "Phocube-Phase Angle Band"){: style="width:225px;height:225px"}
  <figcaption>Phocube: Phase Angle Band</figcaption>
</figure>

<figure class="inline" markdown>
  ![Iss\_WAC\_lat\_figure](../../assets/camera_geometry/Iss_WAC_lat_figure.png "Phocube-Latitude Band"){: style="width:225px;height:225px"}
  <figcaption>Phocube: Latitude Band</figcaption>
</figure>

<figure markdown>
  ![Iss\_WAC\_lon\_figure](../../assets/camera_geometry/Iss_WAC_lon_figure.png "Phocube-Longitude Band"){: style="width:225px;height:225px"}
  <figcaption>Phocube: Longitude Band</figcaption>
</figure>
