Describe EXTRACT_DATA_PIC here.

      SUBROUTINE EXTRACT_DATA_PIC(NTMP,QSZ,SCALE,PICNM,IPL,
     .                     V,UX,UY,UZ,HUSE,HT,CP,SP,EUSE,ETOL,
     .                     FINV,DPIC_DLOC,DIDH,DJDH,Z0,KK,ESZ,DN, DNX)

• INTEGER NTMP
  • NTMP is a global compile parameter that defines the maximum size of maplets (it allocates memory)
    • Standard value is 128
• INTEGER QSZ
  • QSZ is the half size of maplet. width = QSZ * 2 + 1

    • It is derived from READ_MAP

• DOUBLE PRECISION SCALE

  • The scale (both horizontally x and y, as well as verticlally). The values in the MAPLET should be multiplied by this value to get its actual value. Units are in km.

    • It is derived from READ_MAP

• CHARACTER*12 PICNM
  • The name of the image that you want to use. The file is read in (again) in this program)
• DOUBLE PRECISION IPL(2)
  • IPL = Image Pixel Line. Scaling factor to translate from physical to image frame.

    • Comes from V2IMGPLV

• DOUBLE PRECISION V(3)
  • Central vector of the maplet

    • It is derived from READ_MAP

• DOUBLE PRECISION UX(3)
• DOUBLE PRECISION UY(3)
• DOUBLE PRECISION UZ(3)
  • Normal plane of the maplet in X, Y and Z space

    • It is derived from READ_MAP

• LOGICAL HUSE(-NTMP:NTMP,-NTMP:NTMP)

  • Tracks each pixel of the maplet to define if its value should be considered

    • Defined in HGT2SLP

• REAL*4 HT(-NTMP:NTMP,-NTMP:NTMP)

  • HT - Height. The height of the template at that location of the maplet. Used for trying to identifing shadow.
• DOUBLE PRECISION CP(3)
  • Camera vector
    • Calculated in this subroutine
• DOUBLE PRECISION SP(3)
  • Sun vector
    • Calculated in this subroutine
• LOGICAL EUSE
  • "Expanded T1" Flag for when to use the expanded threshold for DN.

    Is a flag set within lithos or lithosp using the 'x' option

    • Uses the ETOL variable
• DOUBLE PRECISION ETOL
  • Expanded T1 flag variable.

    Is a flag set within lithos or lithosp using the 'x' option

    • Typically set to .025 (standard within the scripts for LITHOSP)
• DOUBLE PRECISION FINV
  • Reports the fraction of invisible pixels within the maplet/image intersection
• DOUBLE PRECISION DPIC_DLOC(2,3)
  • This subroutine computes the change in the image-space location (p,l) of a point (x,y,z) on a maplet as the point is moved in the maplet frame.

    • Changed within LOC2PIX that is typically called from this subroutine.

• DOUBLE PRECISION DIDH
• DOUBLE PRECISION DJDH
  • Rate of change for the position I and J in the picture
    • Calcualted in this routine and reported back to who called it
• INTEGER Z0(2)
  • Center point to extract the data from the image.

    • Defined in lithos and derived from IPL. Used in PICINPT and BRT1

• INTEGER KK, ESZ
  • KK is a spacing parameter, which I think is based upon the maplet.
  • ESZ is the size of the array.

    • Defined in lithos. Used in PICINPT and BRT1

• INTEGER DN(-1300:1300,-1300:1300)
  • The workspace of displayed DN for both the image and the maplet (template)
    • Set in this subroutine.

• REAL*4 DNX(-NTMP:NTMP,-NTMP:NTMP)

  • The filled out data that we really want. Set in this routine.

categorySubroutine