SOME CHARCTERSTICS OF THE ANALYTIACL POLTTER JX
Llu Xlanlln
Sun Liye
Llu Sining
Ja WeiPlng
Research Institute of Surveying and mapping
Beijing. Chlna
Some Characteristics of the AnaLltlcal Plotter SYstem JX
Llu Xtanlin
Sun Liye
Liu S1n1ng
Ja Weloing
Abstract
The paper
dlscrlbes some new concepts, new methods of the
Analytical Plotter System JX (made in China),
incLuding the
system structure, the deveLopment to smaLL system, discarding
operational redundancy, menu formation, user's interface, reduced
digital map data, microcomputer-aided servo Logic, generaL
outLine drawing tn media of semi-conductor memory (keep track of
colLecting process),preliminary intelligence and etc.
8y convenient with the cheaper,of higher capacity, more fast
microcomputer, no~ the deslgners could stand at a more advanced
stage than theprivious ones. In order to avoid non-obsolescence of
hardvares in the rapid developing process of microelectronics, and
modefication of softwares, the system should be consistent with the
development of certain series of CPU unit.A new kind of AnalyticaL
PLotter has been des19ned successfulLy by Research Institute of
Surveying & Mapping and Wuxi Instrument Factory of Surveying &
Mappin9 through 4 years efforts(See f19 1).The Characteristics of
the instrument are as foLLows.
Fi 9
1
System Structure
A structure block diagram of AnaLytical PLotter SYstem JX is
shown in fig 2. This diagram can be separated to two parts dlvlded
by a dash Line. Above the dash Line is so called a smaLL system,
and below i t ' s a host comouter.Two parts are connected by a
common memory board and a RS-232 communication line.
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F~9 2 Structure block diagram cf JX-AnaLyt iGaL olatter s/stem
265
Develooment to Sm3ll System
The utiLization of CPU's efficency in previous anaLyticaL clotters
~s not very high, so a foreground terminal must be instaLled to
deveLop the cotentiaLity of CPU.Sut the caLculatton at for~gronud
terminal aL~ays disturbs the normal ooeration of background terminaL
As a pLotting instrument for one cerson, the efflcency of a
expenstve anaL~ttcaL plotter comoare wtth an analog one is only 30%
higher. So a cheap alrphoto coLLector is expected for digitaL
mapPlng in Large area and to set UP various mac data bases.With the
development of microelectronics, this expectation becomes
realizabLe.No~ ~e have developed
such a small system. Its
characteristics are:
*
Speciallzed single board computer 1S utilized and one CPU-for
system.
OnLy one liD \nterface board of full functions
Full solid soft~are,speclfied object code of high QuaLity
nearLy lOOKS, specified operation system
FuLL Lop computation ~ith 8087 lnstructions
Microcomputer aided servo logic
~hoLe
*
*
*
*
When the system is not connected ~ith a host computer, it
can be used not only as a general mapPlng pLotter,but also as a
data collector for aerotrlangulation, DEM and vector. (except
that aerotriangulatton caLculation, DEM \nterpolation and vedio
map) .
The second method of development to small system is discarding
the drawing tabLe, or one d.r~ing bable for several coLlectors, or
put the tabLe
under the controL of workstat'on.
In this case the system is only used for data colletjng, so a
video-map functlon 1s necessary. With the development of
mtcroeLectronics, video map function can also be realized at Lo~
price.After AST~286 is install~d, SmaLL SYstem JX can be operated
under video-function and than visuaL coLLection can be reallzed. At
that tlme aLL of the data and subroutines even loop program ~lLL
be opened to customers.
By thls way.the condition for further enhancement 1S avaiLabLe.
The requirements of users are multi-Level.After one or two years,if
it is desired,the solid state software could be replaced by stngle
chip processor.
Mlcrocomputer-aided Servo-logic
By use of Loop program consisted of BOB7's instructions can be
much more computer time to handle the servo sYstem, for example
coordination-testing program.Neither the Loglc servoboard hard~are
nor the speclfled processor is needed to resolve the servo
computation. It means easy manufacturing
and high
reliabllity.Since the velocity vaLue to po~er ampllfler and the
encoder counts are transmitted directly through BUS, therefore
the testlng programme can be realized easlly: servo oo~er
dmplifier board is onLy regarded as hard~are interpolator,or say
controLable driver of constant velocity. Programmers can calculate
out the veLocity vaLue in terms of expected coordinates,and oresent
oositlon (8253), and const,:;tnt value T. By inputting the veLocity
to the corresponding IIO port,the position feedback Loop is formed.
By comparis'on with the servo Logic, the position feedback reaLtzed
by testing program mare than 300 t~m~s Is discortlnuaL ~del3Y~
feedback. But It \.;iLL be uncticed.
266
To the position feedback realized by software some functions such
3S over-velocity limitation ,acceLeration pre-controL can be added
(drast leal change the moving direct 10n for example). The benef i t·s are:
* The connecting wires are greatly decreased.
* A great amount of hardwares logics are saved.
* More or less smart servo drivers
* More stability
Besides applicat\on of the HOLE components,photocouplera and radiate arrangement of cables brought . The system much more advantages
Menus
A menu of tree structure
regards the operator as a ~pass\ve~
dialoglst.He(or she) becomes more and more muddle-headed,and wouLd
losses interest.The poeration of tree structure menu 1S troubLe-some
You wouLd answer n times 1f YOU want make selection being at (n+1)
Level.So as to simplify the operatton,to resume the operator's and
to easy operations, the menu levels were reduced as possibLe .The
commands are arranged at the same level as posible as it be done.And
the same commands wouLd probabLy occur at the different levels.
For exampLe,all of the commands, provlded by computer manufactures
can be opened to photogrammetrists 1n the mapping orocess,(See Fig 3
).The benefits are below:
Fig 3
It resuLts in:
* The combination of command sequences could be unLlmited
* The updation route is shortest
* Operator's initiative is resumed, and the creation
desire is avaiLable.
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and a fa3t recomoutation C3n be carried.
& 5)
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Fig
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Fig 5 Model set-up
Di,;tin:tive
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Beside the traditional softwares,the some soft~ars of the AnaLytical Plotter system JX has it's own characteristics as follows:
*
*
*
*
*
*
*
*
Preliminary lntelLegence
Chinese characters
Full-screen data edltingd & parameters liD forms.See F19 5
House program: rectangular house program,eaves correction
automatlcal close of muLti-angle house,area caLculation
house tnformatlon table
Precise area calcuLation
Handy,key-directed automaticaL movement
Personal difference adjustment (horizontaL & vertical
parallaxes)
Inner orientation by measurlng principaL points only.
~ig
~
6 FuLL-screen data
ed~tjn9
data of object
197 FuLL-screen d3ta eaitjng of
269
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soac~
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Some software are deveLoped for chinese convention (see figureS).
The general symboLs at the scale of 1:500-1:10,000 are aLL stored
in the symbol library. The movement control is oeculiar too.
Floating mark can be directed by Joy-stick,handwheels,footd\sk,
the Digitlzing Board, and the velocity parameter can be pre-set by
operator on CRT.Compound movement occurs when different controls
are applied on it at same time.
Operation without Redundancy
After statlstic analyses of operator's key operation, one can
found that 'telex' transmitted has a high redundancy_ This isn't
the mistake of operator, but it increases the intensity of operation
Here, a new sp~cification for AnaLyticaL plotters even proposed:
Operational redundance level.
For the reduction of redundant
operations redundancy. We have made a pLenty of work. First, many
single key commands are destgned. Th's is a sort modefication after
a serres of operations on CRT, and enables users to put a sequence
of commands under the defination of a expanded function key. Besides
this, a futher statistic of aLL human's handling operations has shown,
there is also redundancy. A Lot of work has been done on it.
For lnstance, in process of deawlng a enclosed contour line or a
irregular curved line, when fLoating mark approaches the original
point,the instrument would automatically do:
*
Output an absolute vector returning to original potnt to the
dlgital map data area.
* Release pen-up command and cLose the conbined pen-down
* Close time-interval sampling.
* Close distance-interval sampLing or curvature fitting
all of above four functions are carried out automaticaLly,non key
strike is needed.This is so-called operatlon without redundancy,
witch is welcomed by operators.
Preliminary Intelligence
An interchange should exist between operator and programmers,and
the programmers should know what the operators want for. A part of
work has been completed by computer so the labour intensity was
certainly decreased. Shown in Fig 9 (Mapping menu)
*
Point-by-potnt DEM scanning without key operation
* Automatlc return to original point without key operation
* Floating mark goes up and down automatically in DEM
scanning forecasting.
* Footd;sk release when measure contourlng
* AutomaticaL footdisk release when lt is necessary
* Search the mapping window automatically by a single key
* Go UP and down a contour-intervaL by a single key
Pen
head moves away and back.
* There are about 30 standard points 1n the lmage space can
be approached automatlcalLy
These so called inteLligence functions are preLlminary or say a
kind of test. The intelligence functions of the instrument are
not in a linear relation w'th amount of orOgr3ms, but In a
exponent relation.
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Fig 9 mapping menu
Redundancy-free digital map format
Durtng vector digttizing process,the digitaL map data must be
compressed and discarded the redundancy. In other case, the map
digital mapptng is immcossibLe. A compressed m~p data can be
reduced to 1M bytes. Thls kind of mao format 1S:
*,
*
*
*
Every absoLute vector takes 14 bytes
Every retattve vector takes 2 bytes
Every peon COd2 takes 2 bytes and followS-UP 1n force
continually,
Every ASCII ccje interpret words and attribut\on cede
takes 14 byte~, and serves as the the futher interpretation of bas'c Line.
Graphics
Software
and
Intlllegent
drawing
Machine
The drawingtable can be separated as a independent product·wh~ch
is a real CPU-controlLed 'ntelLlgent drawing machine. Beside the
functions of normal straight line interpolat ion, curved Line
f\tt ing, there are some graohic 90ft~ares which couLd be 'nvcked
directly by the system computer:
* P command: Decorate a point w\th several graphics, ant set UP
tn English,
Chinese characters. or Arab'c numeraLs in any place
of its surrounding. Coordinates X Y Z, and letter s'zes can be
changed at ~lll.
* D command: complex pen-do~n command.D command conslst of D and
followed by s~x ASCII codes. ~hich define the lensths of three
intervals.
AD command gives many kind of complex l~nes
* H command: mark hachures ~ith O.01-9.9mm intervals at any
directions in cLosed or ocen poLygon.
272
F command: mark 1n a cLosed or aoen polygon ~lth O.01-9.99mm
tntervals at any direction, including Chinese, English
characters and Arabic numeraLs.
~ S
command: mark any synmboL existed in library at any
position in three sizes.
* WFF: a time -saved double line (~ldenlng) command
* W: a three-foLd symbol cycles along a polygon in 1-9mm
interval,and mark any symboL existed in Library along a normal
line.
All of these commonds can be used reoeatLy and compoundLy. So
a great amount of new commands can be created, among ~hlch only a
few of them are reaLly needed .PLotting files are drasticaLly
red~ced due to the advantage of these inteLligence.
~
Outline
~plott'ngW-DispLay
The editing at a workstatt'on and the collecting process demand a
indicating of digital map.BLind collectior can't
be acceptabLe.
High speed processor is needed when a realtime
dispLay of compressed digital map is required.
About 640k memory space is needed for storing a map at SOOmm x
SOOmm size digitaL map at 0.2mm resolution. This resolution
of digital map correspounds to 40
on photo (Sx magnification)
It is also acceptable for image superlmposation. Under a 8 time
magnification, the line width is 0.3mm. During coLlecting the
lnformatl0n of "bit W mao enters into semiconductor memory from a
port of drawing table.
(a drawing tabLe is not reaLLy needed in this
case). The information of old map enters into the Wb't~ map by
communication after its digitizing.
CertainLy, Nbit N map also can show graphics of image space, but
transformation (only one time) 1S needed in this case.
A vector dispLay made by raster scanning has a lo~er performance
of reaLtime.
But this lower performance has no effect on use. When
Nbit" map develooed to ~byteN map, the coLors can be added to 'to
dis~lay-outllne
User's
Interface
In order to accommodate the varl0us personal characters, a user's
affects its commercial value. So this point must be hold in great
account from beginning to the end. At first there are some problems
in connection with appLication of human engineering.The next is to
model the cartograohre's actions- change the wfree hand N to wfree
fir.ger~-Digitizing Board to direct the move~ent of measuring mark.
In the design of graohic language and menu,the creating initiative
has been considered. The monotonous mapping become intereesting.
Different ef.ficlency would be achieved by different operators.
While the capable operator demand
more higher tranaparancy.
to the user's interface.
Thus, all mapping data wiLL be ooen to users in coupling of
the PC-AT/XT/286/386 by serial port and common data momory. That
means PC users can get aLL mapping data in his own programmes.
Besides, the sub-programmes can be invoked by PC users. At last,
it allo~s the user to deveLop their own LOOP programme on PC.
This is very useful In some particular mappings, but it should be
fast enough.
273
The pO\.Jerful CPU d1scards the mult i-CPU method, as
is the development dlrectlon of
lntegrated circuits,
th~
integrat ion
small in size,
Less connection and more reL ibility. Analitical Plotter JX System
adeots a single board, computation and cantraLL being alL
con c e n t rat, sol ids 0 f t ~~ are ( E PRO M), par all elm e n u, f u l l s ere an. e d 1 t 1 n 9
I/O,fuLL format storage of bit mao.(See fig 10 & 11) The our pose 1S for
reducing the clrcult boards,the connections,the clrcult Levels,the
CPU,the keying times. ALL of these makes the system smaLler, cheaper,
convinient and more reLiable. Wlth the development of mlcroeLectronics~
What a advanced Anatical Plotter ""iLL occur in the futhure.
Fig 10 FuLL mac
fig
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