Home

Quick Links

Software Manual
GitHub
API Reference

Documentation Versions

Latest Release
Dev
8.3.0
8.2.0
8.1.0
8.0.0
7.2.0
7.1.0
7.0.0
6.0.0
3.9.0
3.5.0
USGS

ISIS Application Documentation

skymap

Printer Friendly View | TOC | Home

Convert camera image to a skymap projection

Overview Parameters

Description

This program converts a cube in camera coordinates to a map projection. It differs from the application "cam2map" in that it maps camera ra/dec (right acsension/declination) to map projection longitude/latitude. The program is useful for inflight geometric and optical distortion calibration of a camera when star images are collected. The input cube labels must have an Instrument Group and Kernels Group. That is, the program "spiceinit" should be run on the input cube prior to "skymap".

This program will pick appropriate defaults for most parameters. In particular for the MAP parameter, it will generate the following: 

  Group = Mapping
    TargetName             = "Sky"
    EquatorialRadius       = 1.0
    PolarRadius            = 1.0

    LatitudeType           = Planetocentric
    LongitudeDirection     = PositiveEast
    LongitudeDomain        = 360

    MinimumLatitude        = Computed from the input camera cube or map file
    MaximumLatitude        = Computed from the input camera cube or map file
    MinimumLongitude       = Computed from the input camera cube or map file
    MaximumLongitude       = Computed from the input camera cube or map file
    CenterLongitude        = Computed from the input camera cube at the center of the image

    ProjectionName         = Projection name in the map file
    Scale                  = Computed from the input camera cube or map file
  EndGroup
Note that although the map projection group reflects latitude/longitude, those values are synomous with declination/right ascension.

Note that an important concept here is a Mapping group can come from any PVL file. You can use an existing map projected cube as input for the MAP user parameter. Because the cube has PVL labels and contains the Mapping group, you will essentially force the input camera cube to have the same mapping parameters or match the existing cube. Information about map projections and the Mapping group can be found in the Isis user documentation.

Finally, the user has the option to override the pixel resolution and the ground range (latitude/longitude). These changes can be facilitied through the parameters SCALE, SRA, ERA, SDEC, and EDEC.

In addition, skymap can be used to produce landed mosaics from rovers like MSL. This can be done using ALE to generate an ISD which can be attached to the cube via csminit. The user would then have to update the LongitudeDirection their map file to PositiveWest. This converts the projection from a right ascension/declination projection to an azimuth/elevation projection. Once that is done, the user would run their ISIS cube through skymap and see that the landed rover data would project relative to other images in the same image sequence.

Categories

History

Jeff Anderson2004-12-14 Original version
Jeff Anderson2005-09-21 Fixed bug with program not using all keywords in the user MAP file
Jeff Anderson2005-10-13 Fixed bug with garbage pixels being produced at extremities of the projected image edges.
Jeff Anderson2005-10-17 Fixed bug, full mapping group was not written to cube labels. Also, updated documentation to correctly state that the RESOLUTION parameter is the IFOV of the camera .
Brendan George2005-11-08 Added application test
Tracie Sucharski2006-04-11 Check to see if center of input image projects, if it does, force the tile containing center to be processed in ProcessRubberSheet.
Elizabeth Miller2006-05-03 Redid UI to match cam2map
Elizabeth Miller2006-05-18 Depricated CubeProjection and ProjectionManager to ProjectionFactory
Elizabeth Miller2006-05-30 Moved helper buttons and refined helper error checking
Steven Lambright2007-06-22 Fixed typo in user documentation
Steven Lambright2008-05-13 Removed references to CubeInfo
Travis Addair2009-08-10 Mapping group parameters are now placed into the print file.
Debbie A. Cook2012-12-10 Changed to use TProjection instead of Projection. References #775
Adam Paquette2023-05-01 Updated camera to properly calculate the center longitude. Also allowed users to select PositiveEast in there mapping file.
U.S. Department of the Interior | U.S. Geological Survey
ISIS | Privacy & Disclaimers | Astrogeology Research Program
To contact us, please post comments and questions on the USGS Astrogeology Discussion Board
To report a bug, or suggest a feature go to: ISIS Github
File Modified: 02/21/2025 19:28:14
X

Files: FROM

Description

The specification of the input cube to be projected. The cube must contain a valid Instrument and Kernel group in the labels.

Type cube
File Mode input
Filter *.cub
Close Window
X

Files: MAP

Description

A file containing the desired output mapping parameters in PVL form. This file can be a simple hand produced label file. It can also be an existing cube label which contains a Mapping group.

Type filename
File Mode input
Default Path $ISISROOT/appdata/templates/maps
Default $ISISROOT/appdata/templates/maps/simplecylindrical.map
Filter *.map *.cub
Close Window
X

Files: TO

Description

This file will contain the sky as a map projected image.

Type cube
File Mode output
Filter *.cub
Close Window
X

Output Map Scale: DEFAULTSCALE

Description

This parameter is used to specify how the scale is obtained for the output map projected cube.

Type string
Default CAMERA
Option List:
Option Brief Description
CAMERACompute resolution from input cube This option will automatically determine the scale from the input cube specified using the FROM parameter.

Exclusions

  • SCALE
MAPRead scale from input map file This option will use the Scale (pixels/degree) in the map file.

Exclusions

  • SCALE
USER Get scale from user This option allows the user to specify the resolution using the SCALE parameter. The scale should be entered in pixels/degree.

Inclusions

  • SCALE
Close Window
X

Output Map Scale: SCALE

Description

The number of pixels per degrees (RA/DEC). By default, the program attempts to compute this value as 1 / IFOV of the camera. Note you will typically need to convert IFOV in milli-or-micro radians to degrees. Alternatively, you can entered the scale in the MAP file in pixels per degrees (1 / IFOV). That is, 

              Group = Mapping
                ...
                Scale = 17000.0
              End_Group
              End_Group

Type double
Minimum 0.0 (exclusive)
Close Window
X

Output Map Sky Range: DEFAULTRANGE

Description

This parameter is used to specify how the default ra/dec ground range for the output map projected image is obtained. Note the user can overide the default using the SRA, ERA, SDEC, EDEC parameters.

Type string
Default CAMERA
Option List:
Option Brief Description
CAMERA Compute default range from input cube This option will automatically determine the mininum/maximum ra/dec from the input camera model cube specified using the FROM parameter.
MAP Read default range from map file This option will read the mininum/maximum ra/dec from the input map file. All four values are expected to be defined.
Close Window
X

Output Map Sky Range: SRA

Description

The starting right ascension of the sky map. If not entered it will be read computed from the CAMERA or read from the MAP file, depending on the option chosen for DEFAULTRANGE. If this value is entered, it will override the default value.

Type double
Internal Default Use default range
Minimum 0.0 (inclusive)
Maximum 360.0 (inclusive)
Close Window
X

Output Map Sky Range: ERA

Description

The ending right ascension of the sky map. If not entered it will be read computed from the CAMERA or read from the MAP file, depending on the option chosen for DEFAULTRANGE. If this value is entered, it will override the default value.

Type double
Internal Default Use default range
Minimum 0.0 (inclusive)
Maximum 360.0 (inclusive)
Greater Than SRA
Close Window
X

Output Map Sky Range: SDEC

Description

The starting declination of the sky map. If not entered it will be read computed from the CAMERA or read from the MAP file, depending on the option chosen for DEFAULTRANGE. If this value is entered, it will override the default value.

Type double
Internal Default Use default range
Minimum -90.0 (inclusive)
Maximum 90.0 (inclusive)
Close Window
X

Output Map Sky Range: EDEC

Description

The ending declination of the sky map. If not entered it will be read computed from the CAMERA or read from the MAP file, depending on the option chosen for DEFAULTRANGE. If this value is entered, it will override the default value.

Type double
Internal Default Use default range
Minimum -90.0 (inclusive)
Maximum 90.0 (inclusive)
Greater Than SDEC
Close Window
X

Output Map Sky Range: TRIM

Description

If this option is selected, pixels outside the ra/dec range be trimmed or set to null. This is useful for certain projections whose lines of latitude and longitude are not parallel to image lines and sample columns.

Type boolean
Default FALSE
Close Window
X

Options: INTERP

Description

This is the type of interpolation to be performed on the input.

Type string
Default CUBICCONVOLUTION
Option List:
Option Brief Description
NEARESTNEIGHBORNearest Neighbor Each output pixel will be set to the pixel nearest the calculated input pixel.
BILINEARBi-Linear interpolation Each output pixel will be set to the value calculated by a bi-linear interpolation of the calculated input pixel.
CUBICCONVOLUTIONCubic Convolution interpolation Each output pixel will be set to the value calculated by a cubic convolution interpolation of the calculated input pixel.
Close Window