maplab

The maplab application is used to geo-reference a map-projected cube by adding or updating the Mapping Group with projection and geo-referencing information. Maplab takes as input a map-projected cube and a map file. The user has the option to geo-reference by (LATITUDE,LONGITUDE)-coordinates or by (X,Y)-map-projected-coordinates that correspond to a given (SAMPLE,LINE)-coordinate in the input cube.

The map file must contain information pertaining to the specifics of the cube's map-projection parameters, along with the target, body radius, longitude direction, latitude type and scale. We suggest running the maptemplate program to generate the map file provided as input.

NOTE that when selecting a SAMPLE and LINE for referencing known coordinates to a pixel, pixel coordinate (0.5, 0.5) is the top-left corner of the top-left pixel in the cube. By extension, (1.0, 1.0) is the center of the top-left pixel, and (1.5, 1.5) is the lower-right corner of the top-left pixel.

Description

The cube whose label will be updated with Mapping Group information.

Type	cube
File Mode	input
Filter	*.cub

Description

File containing map projection parameters.

Type	filename
File Mode	input
Filter	*.map

Description

The SAMPLE coordinate in the cube that corresponds to a known (X,Y) or (LATITUDE,LONGITUDE) coordinate. In ISIS, the upper-left corner of the upper-left pixel has coordinate 0.5.

Type	double

Description

The LINE coordinate in the cube that corresponds to a known (X,Y) or (LATITUDE,LONGITUDE) coordinate. In ISIS, the upper-left corner of the upper-left pixel has coordinate 0.5.

Type	double

Description

A list of the different types of coordinates allowed by the application.

Type	string
Default	XY
Option List:	Option Brief Description XY Allows X, Y as Input Values This option allows the user to enter the (X,Y) map projected coordinate (in meters) that corresponds to the given (SAMPLE,LINE) coordinate. This option excludes LATITUDE and LONGITUDE input values. Exclusions LAT LON Inclusions X Y LATLON Allows LAT, LON as Input Values This option allows the user to enter the (LATITUDE,LONGITUDE) coordinate that corresponds to the given (SAMPLE,LINE) coordinate. The (LATITUDE,LONGITUDE) coordinate is in decimal degrees, and must be in the same LatitudeType and LongitudeDomain listed in the map file. This option excludes X and Y input values. Exclusions X Y Inclusions LAT LON

Description

The map-projection X-coordinate, in meters, corresponding to the the given (SAMPLE,LINE) coordinate of the cube.

Type	double

Description

The map-projection Y-coordinate, in meters, corresponding to the given (SAMPLE,LINE) coordinate of the cube.

Type	double

Description

Latitude coordinate, in decimal degrees, for the given (SAMPLE,LINE) coordinate of the cube. It must be in the same LatitudeType listed in the map file.

Type	double

Description

Longitude coordinate, in decimal degrees, for the given (SAMPLE,LINE) coordinate of the cube. It must be in the same LongitudeDomain listed in the map file.

Type	double

Most outside applications use the top left pixel (either upper-left edge or center) to define their location in X, Y. For example, a GeoTiff with an internal header, uses the upper left edge and for an example may report: Upper Left (2883258.0, 979924.0) -- meaning (X, Y). Thus for maplab, one would need to use the same top left corner of the pixel for ISIS, as illustrated in the command line below.

maplab from=input.cub map=projection.map sample=0.5 line=0.5 x=2883258.0 y=979924.0

For this example, the original label already contained a Mapping Group. Object = IsisCube ... Group = Mapping ProjectionName = Sinusoidal CenterLongitude = 227.95679821639 TargetName = Mars EquatorialRadius = 3396190.0 <meters> PolarRadius = 3376200.0 <meters> LatitudeType = Planetocentric LongitudeDirection = PositiveEast LongitudeDomain = 360 MinimumLatitude = 10.76690271209 MaximumLatitude = 34.444196777763 MinimumLongitude = 219.72404560653 MaximumLongitude = 236.18955082624 UpperLeftCornerX = -480000.00000057 <meters> UpperLeftCornerY = 2042000.0 <meters> PixelResolution = 1000.0 <meters/pixel> Scale = 59.274697523306 <pixels/degree> TrueScaleLatitude = 0.0 End_Group ... End_Object

After the command line is run, the original Mapping Group is revised. Object = IsisCube ... Group = Mapping ProjectionName = Sinusoidal CenterLongitude = 227.95679821639 TargetName = Mars EquatorialRadius = 3396190.0 <meters> PolarRadius = 3376200.0 <meters> LatitudeType = Planetocentric LongitudeDirection = PositiveEast LongitudeDomain = 360 MinimumLatitude = 10.76690271209 MaximumLatitude = 34.444196777763 MinimumLongitude = 219.72404560653 MaximumLongitude = 236.18955082624 UpperLeftCornerX = 2883258.0 <meters> UpperLeftCornerY = 979924.0 <meters> PixelResolution = 1000.0 <meters/pixel> Scale = 59.274697523306 <pixels/degree> TrueScaleLatitude = 0.0 End_Group ... End_Object

A typical image that has a "GIS Worldfile", in contrast to an internal GeoTiff header, uses the center of the top left pixel to define its location in X, Y. Thus a Worldfile might look like myImage.wld or *.tfw, *.jgw, *.pgw (depending on image type):

          2.0           Cellsize in X (meters)
          0.0           rotation/skew (normally 0)
          0.0           rotation/skew (normally 0)
          -2.0          Cellsize in Y (meters)
          -24243.731055 Upper-left pixel center X (meters)
          815863.281183 Upper-left pixel center Y (meters)
        

Thus for this example the user would need to run the program with the command line that follows.

maplab from=input.cub map=projection.map sample=1 line=1 x=-24243.731055 y=815863.281183

Say the global file is 1440x720 or 4ppd (and perfectly 0 to 360 lon and -90 to 90 lat). This global case would be run as follows.

maplab from=input.cub map=projection.map sample=0.5 line=0.5 coordinates=latlong lon=0 lat=90

Generally one will try to bring in a polar file which is 0 to 360 lon, extends to a common lat range, and centered at the pole (clat = 90 or -90). Nothing about the extent in meters is needed if the center of the image is again 90 or -90 lat. Again GIS/RS application will still to the upper left pixel but manually this can be harder to use than just using the center which will be defined as X,Y = 0,0 when in a Polar or Lambert Azimuthal projection. Using an example where the polar image is 2000 lines by 2000 samples then the run would look like:

maplab from=input.cub map=projection.map sample=1000.5 line=1000.5 x=0 y=0