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1995-11-01
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D.A.A. Version 2.52D - Demonstration Version
============================================
Legal Notice
------------
This demonstration of D.A.A. (Digital Area Analysis) and its related files
are (C) Wardlaw Surveys 1995. It may be distributed free of charge for
demonstration purposes. A small copying fee is allowable if Public Domain
libraries wish to include it on their discs.
Anyone wishing to distribute this demonstration MUST include all files that
accompany it.
1) Introduction
---------------
Digital Area Analysis (D.A.A.) is a program which calculates areas from
digitised pictures. It has been designed for use by civil engineers to aid
quantity calculations during roadworks construction but will be of use in
many other areas (no pun intended), no doubt. Once areas have been
calculated it is a simple matter to find volumes from them. (Take the
average areas of two sections and multiply by the distance between them.)
This demonstration version has all the features of the full version with the
exception that the calculated areas are random numbers! In the full version
these areas are true to a high degree of accuracy.
2) Using D.A.A.
---------------
A demonstration 'section' is supplied with this application. D.A.A. accepts
sprite files only. These can be from a variety of sources - scanner, video
digitiser, drawfiles etc - with the proviso that, for speed, they are
16-colour (4bpp) sprites. This 'restriction' does not make much difference
in reality as technical drawings are generally in black & white!
Load the demonstration file 'DemoSectn' into D.A.A. by dragging it to the
iconbar icon or to any of D.A.A.'s windows.
When the file is loaded it will be displayed in D.A.A.'s main window.
Alongside this (subject to preference settings) will be a toolbox.
Anticlockwise from the top left these tools are:
Calculations : Area calculations are done 'on the fly'. This tool simply
opens two windows showing the breakdown of the
calculations and their respective totals.
Printer : Sends the area calculation report to the printer. A
printer driver must be loaded to do this.
Save data : Saves the results to a CSV file for importing into a
spreadsheet etc.
Magnify : Alters viewing scale of the current image. This does not
affect the areas obtained!!
Fill : Selects the 'fill' tool. In earthworks a fill is where
the level of the land needs to be raised to lay a road on
top of it.
Cut : Selects the 'cut' tool. Similarly the ground level may
have to be excavated to lay the road. (e.g. into the side
of a hill)
Calibrate : Selects the 'calibrate' tool. Calibration is required at
least once per session. This is what the square above the
roadwork detail is for in the
example section. If the images are obtained using a
hand-scanner it is advisable to recalibrate for every
image to minimise the errors ocurring.
(Hand-scanners are not the easiest of things to operate
over long (A4) distances)
Image Info : Sets the various titles which refer to the current image
which appear in the printout/CSV file.
These tools are also available via the main menu, accessible by pressing
'menu' over the main window. (As you'd expect).
The three tools - calibrate, cut and fill - are all used by double-clicking
select over the area of interest. There are various types of cut and fill -
sand, rock, etc - which can be edited and saved.
3) Preferences
--------------
The user's preferences can be alteres by choosing 'Preferences...' from the
iconbar menu. This opens a window containing a few items in need of
explanation.
Correction factor : This is used if the images have somehow become
enlarged (with respect to the calibration square),
for example if they have been photocopied. Use
this option to compensate for this.
Line colour is : D.A.A. needs to know the colour of the lines in the
drawing for it to be able to compensate for them.
(Lines by definition have zero thickness, but the
finest line a sprite can have is one pixel).
Scanners usually produce a grey-scale from white
(colour 0) to black (colour 15). The example image
has line colour 15 but if, for example the image is
grabbed from the screen using Paint's snapshot in a
16-colour mode the line colour will (probably) be 7.
If in doubt look at the sprite's palette in Paint to
find which colour is black.
Anti-alias image : Usefull if the image is being displayed at less than
100% magnification which usually makes thin lines
'disappear'. This option will make them visible
again at the expense of redraw speed. In any case,
lines which 'disappear' will not affect D.A.A. as it
processes the full-size image.
Use toolbox : Toggles whether the toolbox is displayed.
4) Step-by-Step Tutorial
------------------------
Load the example image into D.A.A. If the line colour (preferences) is not
15 make it so.
Choose the 'Calibrate' tool. This will open a window inviting you to give
the known area of this square. Type a number into the box (e.g. 9 is
commonly used) and click 'OK'.
Move the mouse pointer into D.A.A.'s main window, over the calibration
square and double-click with 'select'. The square should change to blue.
D.A.A. is now calibrated (albeit with a random value) and we are ready to
process it.
Choose either the cut or fill tool and double-click over an area of interest.
This area will change orange or green depending on which tool is selected.
In the full version of D.A.A. while this is happening the area is calculated.
D.A.A. is so fast there is hardly any difference in speed between this
version and the full one.
When you have finished selecting areas you can view the results by clicking
the calculator icon.
As a guide to which areas should be cut and filled refer to the 'Final' file
with this application. The draw file 'DemoFile' shows typical details of a
cross-section, for those not familiar with road construction drawings.
5) Notes about image files
--------------------------
The areas in the image (sprite) file which are required to be processed
_must_ be completely closed - even a single missing pixel will cause the
'flood-fill' to spill out of the area.
Poor lines can be patched up by dragging adjust over the image in D.A.A.
this allows lines to be drawn (in the image's line colour) to patch up the
image.
Although each image can take up a great deal of space, most of it is empty
and for this reason it is possible to compress an entire contracts details
onto a single floppy disc. SparkFS is ideal for this.
6) Obtaining the Full Version
-----------------------------
The full version of D.A.A. costs £199+VAT and can be obtained from the
following address.
Wardlaw Surveys
Wardlaw House
Kirkhill
Inverness-shire
IV5 7PB
Scotland
Tel/FAX 01463 831214
We are authorised Acorn dealers and are therefore able to provide a complete
system to suit your needs.
The full version comes with manual, calibration square overlays and technical
support. Also included is a copy of Draw2Sprite which allows drawfiles to be
converted into sprites. Many surveyers packages can export files in DXF
format which Draw can import, meaning that the sections need not be scanned
in.
Iain F. McLaren
31.10.95