How To Build A Landmark

Objectives

First we will generate a maplet with the following parameters:

center at -10, 350 (lat,wlon)

scale = .001 km/px

size:

Q=49, width=99 x 99 px

name = ‘START5’

LITHOS: Create New Landmark

lithos

c - create new landmark name

START5 - landmark name

l - define landmark control point by specifying a latitude and longitude on the body

-10 350 - lat, lon

.001,49 - enter scale (km/px), qsz

LITHOS:Input the new landmark

Once the landmark is created, you need to "load" it into active memory. You use the lithos command "i" from its main menu.

i - input landmark

START5 - landmark name (as previously named)

y - check for images?

0.5 - fractional width. (This is almost always used)

n - reject invisibles

In a second terminal, review the LMRK_DISPLAY1.pgm image. You can use ImageMagick's "Display" command, Graphics Converter, or if using a Mac, pgm files can be displayed in the Finder or Preview.

cd <working dir> ls -lt | head display LMRK_DISPLAY1.pgm

You can also use the SPC_Tools: landmarks

LITHOS: Eliminate Pictures from Landmark

e - eliminate pictures from landmark

n - auto-eliminate new images only (a for auto-eleiminate)

0,50,.6,.6,0,4 - Input INVLIM,SLIM,CLIM,ILIM,RSMN,RSMX

0 is typical.

If you have objects that are obscuring the maplet, then this becomes important

50 is the emission angle that we keep

.6 means the image must fill at least 60% of the frame

.6 means the illuminated service must fill at least 60% of the frame

0 is minimum resolution -- almost always is 0

4 is the maximum resolution ratio (how many times bigger are the image pixels than the GSD.

3 or 4 is typical.

6+ is seldom effective)

INVLIM = 1000 * MAX INVISIBLE FRACTION (0-1000)

SLIM = MAX EMISSION ANGLE (0-90)

CLIM = MIN FRACTION OF VISIBLE (0-1)

ILIM = MIN FRACTION IN SHADOW (0-1)

RSMN = MIN IMGSCALE/MAPSCALE (0-inf)

RSMX = MAX IMGSCALE/MAPSCALE (0-inf) =>set according to printout and LMRK_DISPLAY

Most permissible: 1000,90,0,0,0,inf => does not throw any image away

Least permissible: 0,0,1,1,inf,0 => throws all away

display LMRK_DISPLAY1.pgm

LITHOS: Get Heights from Shape and Find Normal, V

m - get heights from shape model

n - find normal

2 - normal from heights

m - get heights from shape model

u - update landmark file (save)

1 - save map

In 2nd terminal:

cd Bennu ls -lt | head display LMRK_Display1.pgm more LMRKLIST.TXT more LMKFILES/START5.LMK more MAPFILES/START5.MAP showmap START5

Then display the START5.pgm (xv, imageMagick, convert, GraphicConverter)

LITHOS: Align Landmarks in Pictures

Option 1. Use this when the template you see in LMRK_DISPLAY1.pgm is poor	Option 2 (typical). Use this as much as you can
1 - align landmarks	1 - align landmarks
3 - align with picture	0 - align with template
23 - picture #2 in LMRK_DISPLAY	3 - enter spacing
1 - enter spacing	n - new spacing?
y - new spacing? Yes b/c it only aligned a few images	0 - continue
2 - enter spacing	y - update landmark pixel locations?
y - new spacing? Yes b/c it only aligned a few images	1 - align landmarks
3 - enter spacing	0 - align with template
y - new spacing? Yes b/c 3 caused a couple images to shift>10px	1 - enter spacing
2 - enter spacing	n - new spacing?
n - new spacing? No, lets just use the correlated images first	0 - continue
0 - continue	y - update landmark pixel locations?
y - update landmark pixel locations?
1 - align landmarks
3 - align with picture
1 - picture #2 from last iteration became picture #1
1 - enter spacing
n - new spacing?
0 - continue
y - update landmark pixel locations?

display LMRK_Display1.pgm

LITHOS: Find Template

u - update landmark file (save)

1 - Save map

0 - find template

c - use correlated

.5 - enter correlation limit

0 - find template

0 - continue

44 - number of iterations

display LMRK_Display.pgm

LITHOS: Align Landmarks and Find Template

1 - align landmarks

0 - auto align

1 - enter spacing

y - new spacing?

2 - enter spacing

n - new spacing?

0 - continue

y - update landmark pixel locations?

1 - align landmarks

0 - auto align

1 - enter spacing

n - new spacing?

0 - continue

y - update landmark pixel locations?

display LMRK_Display1.pgm

0 - find template

c - use correlated

.5 - enter correlation limit

0 - find template

0 - continue

44 - number of iterations

display LMRK_DISPLAY1.pgm

REPEAT ONCE

LITHOS: Solve for Heights

2 - find heights

8 - fill with shape

2 - include existing heights

.01 - input fraction of points

1 - auto include neighboring maps

4 - include limb vectors

1,2.5,3 - input expansion, res/scale limit, d_hgt limit

6 - include differential stereo

y - use gradients?

y - autoheights?

0 - begin iteration

.025 - input weight

30 - enter number of iterations

0 - end iterations

display LMRK_DISPLAY1.pgm display slope.pgm

LITHOS: Final Alignment and Save

1 - align landmarks

0 - auto align

1 - enter spacing

n - new spacing?

0 - continue

y - update landmark pixel locations?

# We are skipping V-4 fo