[Lapg] [permaculture] Permaculture GIS/CAD

Sun Apr 3 07:22:50 PDT 2005

Hello People,
I trust that this greets you and all well.
I have used MapInfo Professional (GIS) and Microsoft Excel for all of my 
design work (mostly broadacre) for about 10 years now. These two products 
link together (OCE) and make the process of design very quick and easy. On 
most of the PDC's I have taught on I have delivered a module on the subject 
and how I apply the technology.
As with any mapping the accuracy of the detail and ultimately the output 
are limited by the quality of the input data. Some maps on which I have 
based my plans on have been horrendously inaccurate, one more recently here 
in Viet Nam (an US Army Engineering Corp Map no less) had a creek going 
through a hill that didn't exist. Message here is to ground-truth your base 
map data to outwit the inevitable inaccuracies.
In response to this situation back in about 1998 I in most cases stopped 
using government topographic maps for detail plan development and hired a 
surveyor (with an Electronic Distance Module or EDM or Total Station) who 
was able to generate a sub-mm accurate plan of the property. Main reason 
for this was that my contracting business was haemorraging as a result of 
innacurate base maps that were creating really innacurate Bill's of 
Quantities. I must have missed that part in my PDC's....Had to learn the 
hard way...
This is a technology available in many countries and is the way to go if 
you want a highly accurate base map. In most cases the contours will be at 
0.5m intervals and all property features are "picked up". Using this detail 
we then used a program called Civil CAD to design all of the earthworks - 
again a highly accurate procedure - whereby we could match as closely as 
possible cut and fill volumes: obtaining the optimal storage ratio of a site.
I have also trialled AutoCAD and AutoCAD Land Desktop and whilst they are 
fantastically capable are way over the top and generally great for wasting 
time on the anal retention of unnecessary detail where you are placing 
trees etc. Better to cut to the chase and save the detail for the on ground 
works. However if tree symmetry is your bent (as it has been unfortunately 
for many of my clients) then this type of design software is 
extraordinarily useful - unless you want to go batty marking out 
symmetrical layouts in the field. Once you design it on the screen then the 
design data gets put back into the Total Station memory and out goes the 
surveyor and the instrument tells you where the trees should be placed. We 
even got to the stage where we could make the tree's planted in parallel 
keyline contour offset rows all line up and look really pretty - of course 
the trees couldn't give a, but the client is all warm and cuddly.
Maybe a chance of getting over to the US sometime this year so if I do I'll 
have to slip into a PDC somewhere and help out if wanted with the PC/GIS 
module mentioned.
Good Luck and Tam Biet from here in hot (37 degree celcius) and humid Dong 
Xoai (100km north west of HCMC/Saigon - south central highlands of Viet 
Nam) - I'll get back to welding up some FC tank forms for the locals here - 
great day for it - not!!

Cheers,
Yours and Growing,
Darren J. Doherty
Integrated Consultant/Lecturer
M&M's/Mars Inc., ACDI/VOCA
Sustainable Cacao Agroforestry Systems (SCAS) Project,
Forest Science Institute of Vietnam (FSIV) Research Farm, Huong-lo 312, 
Nghia Trung Commune, Bu Dang District, Binh Phuoc Province,
Socialist Republic of Vietnam
m. +61 (0) 418 254 605 (Australia)
m. +84 (0) 919 371 628 (Viet Nam)
e. darren at permaculture.biz
w. www.permaculture.biz
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