ISO_ILBM (c) COPYRIGHT 1992 Bill McCarter NO Rights Reserved

Legal:

   This program is PUBLIC DOMAIN. Copy it and distribute it to
your friends, as long as you include all the files that are in
the archive file ISO_ILBM.lha. I will not allow anyone to make a
profit from this program, except a modest charge for copying and
media, such as the Fred Fish collection.
   The program is fully operational, it is a simple utility with
very little error checking and without an intuition interface.  

PURPOSE:

    The purpose of this utility is to assist DEMMER1 digitize
contour maps into VISTAPRO DEM's. 

HOW IT WORKS:

   Any IFF graphic of any resolution may be used, in any
resolution or screensize as long as you have the chip ram. Even
Brushes may be used. Other numbers of colours than 64 work but I
don't recommend to use them. 64 colour halfbright ILBM's produce
the best results and HAM doesn't work. If you are serious about
graphics then you owe it to yourself to get a program like
Pixmate or ADPro anyway to do any format conversions.
   The elevations are taken from the colours themselves, with
palette 0 being the minimum elevation and palette 63 being the
maximum. This provides 64 steps in elevation for the image which
should be enough for most applications. If not, DEMMER1 has a
few processing functions that I have provided to smooth out the
transitions.

OPERATION:

   ISO_ILBM operates from the workbench by double clicking on the  
icon. 

IMPORTANT!!!

    Sometimes I have found that programs written in AMOS will
seize up the computer when they start. I believe this is because
there is not enough unfragmented memory available or a conflict
getting a resource allocation. I have never had a problem when
starting from a fresh boot. If this program fails to start and
just gives you a black or a blue empty screen, reboot and try
again. I'm sorry for this but there is nothing I can do about
it. I would write more often in C but, writing in AMOS is, at
least ten times faster and the programs do work.   
          
    What this program does is make it a heck of a lot easier to
digitize a contour map. I have included an example ILBM to show
how it is used. Import the Picture into a paint program that can
work on 64 colour extra half bright IFF's. You will notice that
the background colour on the picture is colour 0. The lines on
the map are every fifth contour from a topo map.
    To make your own map:

1: Start a 64 colour picture in a paint program. I prefer to use
a square format such as 320 X 320. This example, though is 320 X
200.
2: Make a grid on the picture using colour 1. I usually use a 40
X 40 grid.
3: This grid represents a grid on your topo map such as the
Universal Transverse Mercator Grid.
4: Find the highest elevation on your map, and the lowest and
count the contour lines between them.
5: Divide this number and round down to the nearest integer. This
is the colour spread between contour lines.
6: Pick colour 64 and draw the top contour line, using the grid
as a guide.
7: Count down on the palette the number of the colour spread, and
use this as the colour for the next contour line.
8: Repeat until all the contour lines have been drawn.
9: Fill in all the grid lines to colour zero.
10: Process the picture using ISO_ILBM and go to bed. It should
be done by morning.

    This program is dead slow due to the large overhead in the
search routines. These search to find the greatest slope between
contour lines and then uses these values to calculate the
intermediate colour. The less complicated your map the longer
the search routine takes.

   This program multitasks well. To toggle to and from workbench
press Left Amiga-A. To kill the program at any time type
Control-C.
 
   If you like this, or if you would like anything else in the
programming line in C, assembly or AMOS or have an interest in
mining and mineral processing or design engineering, including
digital design please drop me a line to:

GYRUS SOFTWARE GROUP
Bill McCarter
P.O. Box 250
LILLOOET, BRITISH COLUMBIA,
CANADA,
V0K 1V0 
or COMPU$ERVE 72570,3622.

VISTAPRO (C) is a COPYRIGHT of Virtual Reality Laboratories,Inc
Pixmate (c) is a COPYRIGHT of Progressive Peripherals Inc AMOS
(c) is a Copyright of Mandarin Jawx and is a fantastic way to
access the power of the Amiga.