Do these make any sense?

yardbellAI and Robotics

Nov 14, 2013 (3 years and 6 months ago)

67 views

Do these make any sense?

Navigation


Moving the viewpoint as a cost of
knowledge

Navigation


Metaphors and methods


Affordances


Ultimately about getting information



Geographic Space


Non
-
metaphoric navigation

The affordance concept


Term coined by JJ Gibson (direct realist)


Properties of the world perceived in terms
of potential for action (physical model,
direct perception)


Physical affordances


Cognitive affordances

World
-
in
-
hand

Path drawing

Flying Vehicle Control

Walking interface

Walking
-
on
-
the
-
spot interface


Use in virtual reality system


Actually a head bobbing interface.



Real
-
walking both more natural and better
presence than either flying or walking on
the spot.

Evaluation
(Ware and Osborne 1990)


Exploration and Explanation


Cognitive and Physical Affordance


Task 1: Find areas of detail in the scene


Task 2: Make the best movie


For examples see classic 3D user interaction techniques

for immersive virtual reality revisited

World
-
in
-
hand

Good for discrete objects


Poor affordances for looking
scale changes


detail


Problem with center of
rotation when extended scenes



Flying Vehicle Control

Hardest to learn but most flexible


Non
-
linear velocity control


Spontaneous switch in mental model

The predictor as solution

Eyeball in hand

Easiest under some
circumstances


Poor physical
affordances for many
views



Subjects sometimes
acted as if model were
actually present

Map:

ahead
-
up

versus

track
-
up


North
-
up for shared


environment



Ahead
-
up for novices



View marker gives
best of both

Mental maps


How do we encode space?

Seigel and White


Three kinds of spatial knowledge

1)
Categorical (declarative) knowledge of
landmarks.

2)
Topological (procedural) knowledge of
links between landmarks

3)
Spatial (a cognitive spatial map).


Acquired in the above order

Colle and Reid’s study


Environment with rooms and objects


Test on relative locations of objects


Results show that relative direction was
encoded for objects seen simultaneously
but not for objects in different rooms


Implications: can generate maps quickly:
should provide overviews. (ZUIs are a
good idea)

Lynch: the image of the city

Lynch’s
Types

Examples

Function

Path

Street, canal,

Transit line

Channel for
movement

Edges

Fence,
Riverbank

District limits

Districts

Neighborhood

Reference

Region

Nodes

Town square,

Public building

Focal point for

travel

Landmarks

Statue

Reference point

Vinson’s design guidelines


There should be enough landmarks so
that a small number are visible.


Each Landmark should be visually distinct
from others


Landmarks should be visible at all
navigable scales


Landmarks should be placed on major
paths and intersections of paths

Non
-
metaphoric Focus+Context


Problem, how not to get lost:


Keep focus while remaining aware of the
context.


Classic paper:
Furnas, G. W., Generalized fisheye
views.
Human Factors in Computing Systems CHI '86
Conference Proceedings,
Boston, April 13
-
17, 1986, 16
-
23.


Non metaphoric Interfaces


ZUIs Bederson
-
Zooming


Focus in context


Using 3D to give 2D context

Dill, Bartram, Intelligent zoom

Perspective wall

www.thebrain.com

Table Lens

http://www.nass.usda.gov/research/Crop_acre97.html

POI Navigation MacKinlay


Point of interest.


Select a point of interest


Move the viewpoint to that point.



VP

+ View direction reorientation.

Dist =

start

C

t

Center of Workspace Navigation


COW navigation


Move objects to the center of the workspace.
Zoom about the center.


Initially object
-
based became surface
-
based


exponential scale changes d = k
t


: a factor of 4 per second (10 sec ~ scale by a million)


Better for rotations (people like to rotate around
points of interest)

COW Navigation in Graph
Visualizer 3D

Viewpoint

COW

The Concept: Translate
to center of workspace
then scale

GeoZui3D

Zooming + 2 dof rotations

Translate point on surface to center

Then scale. Or translate and scale. (8 x per second)

Navigation as a Cost of Knowledge.
How much information can we gain
per unit time



Intra
-
saccade (0.04 sec) (Query execution)


An eye movement (0.5 sec) < 10 deg : 1 sec>
20 deg.


A hypertext click (1.5 sec but loss of context)


A pan or scroll (3 sec but we don’t get far)


Walking (30 sec. we don’t get far)


Flying (faster , but can be tuned)


Zooming, t = log (scale change)


Fisheye (max 5x). DragMag (max 30x)

Generalized fisheye views

George Furnas


A distance function. (based on relevance)


Given a target item (focus)


Less relevant other items are dropped
from the display.

#include <GL/glut.h>
void redraw( void )
void motion(int x, int y)
{
rx = x; ry = winHeight - y;
}
void mousebutton(int button, int state, int x, int y)
{
if (button == GLUT_LEFT_BUTTON
&& state == GLUT_DOWN)
{
rx = x; ry = winHeight - y;
}
}
void keyboard(unsigned char key, int x, int y)
int main(int argc, char *argv[])
{
glutMouseFunc( mousebutton);
glutMainLoop();
}