Surveyors 1:1 vs Landscape Architects 1:1

I work as a landscape architect and was always taught to draw at fullscale within model space (i.e. where 1 unit is the equivalent of 1 millimeter). However it seems surveyors have been instructed differently and any survey work that I have requested to be drawn at 1 to 1 in model space invariably returns at 1 to 1 with 1 unit being the equivalent of 1 meter. It then means I must scale the model space drawing up 1000 before I can begin work on it.

Anyway question:

More and more contractors that I appoint now request the dwg. file of my drawings so they can set out directly from the GIS information embedded in the drawing. Could anyone advise as to whether this scaling up 1000 times will adversly affect the GIS information? If so would scaling back 1000 times fix the problem?

Clear as mud?

Providing you have not rotated the dwg and you know the co-ords of 1 point you should be able to scale 0.001, errors will creep in but you would need a significant length to start getting small mm errors, gps will take into account curvature of the earth and then you need scale factors.

Surveyors and architects have different usage for coordinates depending on the scale of works.

When one is dealing with mapping the countryside, the metre is a natural unit to work with. When one is dealing with houses, the millimetre is a natural unit to use.

I am surprised that a landscape architect is using millimetres. I would have thought that metres would be sufficient.

As long as you scale up/down about point 0,0, you will not go far wrong. What sort of accuracy are you looking for? I would have thought that a tree's position would not matter to +/- 200mm

I would have thought that a tree's position would not matter to +/- 200mm

That would depend on if that amounts places the tree to close to the house.

AS Eldon stated, scale about the 0,0.

Try using -DWGUNITS (include the -) and set it to automatically scale inserted items.

Command: -dwgunits
Drawing units:
 1. Inches
 2. Feet
 3. Millimeters
 4. Centimeters
 5. Decimeters
 6. Meters
Unit for length <1>:
Drawing unit display formats:
 1. Scientific
 2. Decimal
 3. Engineering
 4. Architectural
 5. Fractional
Linear display format <4>:
Architectural linear display precision formats:
 0. 1"
 1. 1/2"
 2. 1/4"
 3. 1/8"
 4. 1/16"
 5. 1/32"
 6. 1/64"
 7. 1/128"
 8. 1/256"
Linear display precision <5>: 4
[b][u]Scale objects from other drawings upon insert? [Yes/No] <Yes>:[/u][/b]
[b][u]Match INSUNITS to drawing units? [Yes/No] <Yes>[/u][/b]:

That would depend on if that amounts places the tree to close to the house.

I never knew that nature grew roots to within 8" --- clever stuff

I never knew that nature grew roots to within 8" --- clever stuff

Tell that to the code inspector.

Thanks all,

Eldon - common assumptions are made about the nature of the work of a landscape architect.. I basically deal with any spaces that aren't buildings, from streetscape upgrades, shopping malls, playgrounds, sportsfields, residential gardens etc.. As such it amounts to more than a positioning of tree. This is why the positioning of items within the landscape are crucial.

SLW210 - thankyou very helpful information.

Although I am quite proficient in the use of AutoCAD as a drafting tool I am not to clued in as to how it works with GIS co-ordinates etc. I am assuming though that the units used when drafting do not affect the GIS information.. however I guess I also assumed that the scaling of any drawing after drafting woruld?

If you have to use millimetres for your units with landscape surveying, you do have my sympathy.

If you care to look at the "Units and Scales" tutorial on this forum, Landscape Architects and Civil Engineers are both said to use metre units.

Am I drawing in metres or millimetres?

Most people who use AutoCAD, draw using decimal drawing units. What these drawing units represent is entirely up to the individual. However, you must decide what units you will use before you start drawing. One drawing unit could represent one millimetre, one centimetre, one metre, kilometre, mile, furlong or fathom. It is entirely up to you. However, in most parts of the world it is common practice to work in either millimetres or metres. Which of these two units you use will largely depend upon the type of drawing you are creating. For example, if you were creating a detail drawing of a flight of steps, you would most likely use millimetres (Architects will almost always use millimetres). If, on the other hand you are drawing a landscape masterplan, you would probably want to work in metres (Landscape Architects and Civil Engineers usually use metres).

Eventually, you will come to see that metres are sufficiently accurate, with the third decimal place being millimetres.

Be careful scaling using 0,0 you want to end up with real world co-ords or else your GPS will be in the next block of land. you may need to do a scale then a move you have no idea generally if the plans were scaled from metres to mm which point they picked as the base point not every one use 0,0.

The units command will scale the drawing automatically for you. Although I am not sure if it affects the it's relation to (0,0). I would think not.

In my opinion 1:1 in metres is the correct way. I.e. the surveyor(s) are correct and the architects are wrong.

In my opinion 1:1 in metres is the correct way. I.e. the surveyor(s) are correct and the architects are wrong.

+1. The SI unit of length is the metre not the millimetre.