Measuring area from bitmap. Should I buy Illustrator?

[brian_fielder@adobeforums.com]

I have been contemplating buying Illustrator for some time, but have not been sure that my only occasional need would justify the expense. Now a new reqular job has come up that requires me to buy a program, but I have been unable to find out from the FAQ and knowldege base if I can do it rapidly in Illustrator.

Working from a jpeg images of sailboats, I need to create a scale for the rulers from one known dimension of the boat. Typically this would be length or mast height. Then I need to get the required data, which is the lenth of other elements on the bitmap (typically sail dimensions) and, more equally importantly, the area of sails that have curves in the planform.

The job nees to be done very quickly - just a couple of minutes per image.

I know that there are cheaper soluitions that could do this. However, there would be other benefits to having Illustrator and there is a lot to be said for sticking to one program for related tasks. (I already have Photoshop (6.0), and would probably go for the Creative Studio.)

Many thanks for helping out a Newbie.

-brian

[BobHill@adobeforums.com]

Brian,

Although you can sort of do this in Illustrator (Control R makes the rulers available) and you can make line dimensions from any lines you draw.

You can also do this in PhotoShop or actually any other raster image program. Just print the image to a reasonable size and use a set of dividers to pick your dimensional areas and place this to an accurate physical measuring device. Be aware, of course, that due to perspective, your boat is NOT going to show actual dimensions the further away from the lens it goes, and it depends upon the quality and type of camera lens that took the picture to begin with. So true accuracy wouldn't be available to you from ANY photograph.

Bob

[Philip_Peterson@adobeforums.com]

The following thread might be of use.

Harron K. Appleman "Measure or Calculate Area of a polygon" 4/29/04 8:43am </cgi-bin/webx?13@@.3bb3d75f/1>

[Poul_Solbjerg_Holst@adobeforums.com]

This could be done fairly easy with Illustrator and the Cad Tools plugin
from Hotdoor.

Poul Solbjerg

[brian_fielder@adobeforums.com]

Thanks everyone. Looks like CAD TOOLS might be needed for the efficiency I want. Looks nice. Another $250 though :(

[James_E._Talmage@adobeforums.com]

"Another $250 though"

Although you should buy the Creative Suite anyway, my advice would be use a program for this project which has better support for custom ruler units, has built in info features for area & path length, and dimensioning tools. Canvas has all three, and is probably available at an attractive competitive side-grade price for less than you would spend on plug-ins.

Don't get me wrong. Cad Tools is fine and I have a copy. I just don't like bread & butter functionality (which should be built into any program called "Illustrator" anyway) being wholly dependent upon third-party add-ons.

JET

[brian_fielder@adobeforums.com]

James

You d'man. I dowloaded a trial version of Canvas - 5 min
Read the help on how to set the scale and measure area - 5 min
Did the first trial job - 2 min

I can do what I need in the minimum number of mouse clicks I could imagine. I am very thankful for your help.

Brian

[Kurt_Gold@adobeforums.com]

I don't know how it is in the U. S. but here Canvas 6 and even 7 is a magazine supplement at a very attractive price of zero $

[BobHill@adobeforums.com]

Folks,

Regardless of the program, AutoCad, Hotdoor Plugin for Illustrator, Illustrator itself, etc., (all have dimensional tools) unless you also have a perspective measurement grid along with the raster image of a boat, there is no way to obtain accurate dimensions from that image without knowing the dimensions to begin with or unless there is a lens perspective forumal to determine it. The larger the vessel, the more accuracy you'll lose. You might be able to determine from facts (height of a mast, size of a buoy, cleat, positions, etc.), but not from the image itself. For instance a 28mm lens will give you a different perspective than a 300mm lens .. drastically.

Bob

[Philo_Calhoun@adobeforums.com]

There would be lots of ways of doing it, but if my job depended on this type of work as a main part, I'd use a CAD program rather than using a vector illustration or bitmap program. The advantage to CAD is that not only can one determine areas, but one can measure and label any length one desires and one can work with actual dimensions. I use AutoCAD for this sort of work, but any 2D CAD program would work.

[James_E._Talmage@adobeforums.com]

"Regardless of the program, AutoCad, Hotdoor Plugin for Illustrator, Illustrator itself, etc., (all have dimensional tools)"

Pray tell. And where are the dimensioning tools in AI itself?

"...there is no way to obtain accurate dimensions from that image without knowing the dimensions to begin..."

Brian already stated that he is working from a KNOWN dimension to establish his scale. (But AI lacks customizable scales).

It is quite obvious that Brian is in need of *approximate* values. My guess is for the purpose of a boat surveyor or re-seller. Bob, haven't you ever had someone give you an estimate on a roofing or painting job? Contractors quite often hold transparencies at arms length to "measure" roof pitch, etc. I've designed (or at least priced) many a sign project myself on the basis of measurements estimated in exactly the way Brian is pursuing.

"...if my job depended on this type of work as a main part, I'd use a CAD program..."

Brian cited "occasional" but "regular" use. A full blown CAD program would be gross overkill for this purpose--especially given that he IS working from photos; that is, he is dealing with reasonable estimates. He's not DESIGNING the boats. ;-)

"The advantage to CAD is that not only can one determine areas, but one can measure and label any length one desires and one can work with actual dimensions."

To do those things all you need are customizable ruler scales, perimeter and area readouts, and dimensioning tools. Which is why I recommended Canvas. Canvas is quite a capable "poor man's CAD program. (Deneba also created Deneba CAD.)

"For instance a 28mm lens will give you a different perspective than a 300mm lens .. drastically."

Bob, I wonder if you happen to know that a crop of an image taken with a short focal length lens can be practically indistinguisable from an uncropped image taken with a longer lens?

;-)

JET

[brian_fielder@adobeforums.com]

Many thanks to all. It is very interesting to see the variety of suggestions. For the sake of interest I will clarify what I am doing:

I creating a web resource on sailing multihull boats. Part of the info I am generating is a rating of potential performance based on parametric data. For this a sail area parameter is needed which is the mainsail area plus the area of the fore-triangle (not the actual area of the forsails). These data are usually not readily available hence the need to make an estimate. More often than not I can get a small jpeg of the sailplan (showing the boat and sails)- too low res to read dimensions but knowing the boat lenght all can be estimated with a convenient tool I am seeking. A reasonable side-on photo will also suffice - conveniently multihulls don't heel over too much. I don't need high precision.

I am sure the Canvas suggestion is very suitable for me, though all ideas were of interest. It is so quick. Furthermore, there is a fringe benefit I had not previously though of. I can rapidly outout my dimensioned graphic to the web should I wish to.

brian

[Philo_Calhoun@adobeforums.com]

Some of the simpler CAD programs are cheaper than Illustrator. I think one of the basic turbocad programs goes for around $50. I haven't used Canvas, so I can't comment on the comparison. I think buying Illustrator for this would be getting the wrong program.