Converting Picture to CAD Object

if I understand, you want to change raster to vector format.

Try this.

Insert it into a drawing, export the picture out as a metafile. Then import it in.

I have to withdraw that suggestion.

I just tried it.

That proceedure only works with text.

Try this,

http://www.img2cad.com/

What I'd like to do is take an aerial picture of, say, an intersection, and then, convert it to a cad file. If I have a known dimension on the ground, could I establish a scale so I could get other dimensions (measurements)? This would really be handy for analysing traffic accidents, measuring land, buildings etc. Of course, a simple method of taking the picture would be required. With all the remote controlled helicopters, balloons, etc., this should not be a problem.

I know this can be done with Google Earth, but I'd like better resolution.

Have some fun today,

PAPADOC

RMFR

Try the local county extension office. They do have photos that they take for plant maps and acreage for area farmers. These are very accurate.

Most County Planning Departments have the mapping you require. Most of it is done with GIS, but some others have old maps. Check 'em out. For a small fee they can convert the maps into drawing format (*.dwg, *.dxf).

If you're lucky to have a progressive county, then you may even find the applicable maps online at that level of government. Ditto with your various state departments, including the state DOT. And don't forget the US Ag Dept. and FEMA, and other Federal agencies...even NASA! Depends on what you are seeking....

Some CAD packages (i.e., Vectorworks) have a tool to convert bit mapped images to objects.

However, the degree of success varies and sometimes line thicknesses make the task difficult. You may find the results frustrating.

Lastly, photographing with a camera will create optical distortion of the map. If you do not believe it, photograph a large sheet of graph paper and then look at the photographic results.

Some software such as Photoshop have correction factors that you can apply to help. The amount of distortion is lens dependent and is not always a simple pin-cushion distortion, but a complex pattern.

The best alternative is to digitize the map using a line scanner or flat bed scanner.

If you already have the maps in Autocad, why all the bother converting?

Back in the 80's, I wrote a conversion program, that converted DLG (Digital Line Graph) Satellite imagery from the USGS to a DXF. Had ideas of updated area platmaps.

Depending on the complexity you may be farther ahead instead of tracing but to contact a cartographer or if your are a cartographer, try the USGS.

Another one to try is Aide pdf to DXF converter

http://www.aidecad.com/

Of course you need to somehow get the scale correct, and, bear the other comments here in mind.

To convert from a digital photo to plan is possible. The direction to any point from the center point of the photo is always correct and on a flat surface like a plan the correct distance can be calculated rather accurately.

The distortion is less with the subject further away from the camera.

Generally, the distortion is less as the focal length goes up.

However, lenses create other distortions such as pincushion, barrel, or a wavy-line/mustache distortion which is a combination of the first two.

No lens is going to be free of this and the degree of accuracy required for the end result may render the camera approach difficult or useless.

A flat bed or line scanner is the only way to get a true representation of the original.

Chart needs to be placed on a parabolic surface to make all points on the map equidistant from the camera. I have seen these used in Ottawa, cartography department. Making map pix, no need for CAD input. They keep the camera about 15 feet away, so the curvature is minimized/tolerable and have it well lit and they used a multimegapixel camera head.

This produced a simple undistorted picture.

To intake to CAD, you can use the mentioned programs, but there is a large need for editing on CAD programs to introduce the third dimension because the conversion program cannot extract the vertical component to create a vector diagram. This is time consuming and requires someone who knows the program well.

Theoretically, it would not be parabolic, just curved or semicircular.

True, a portion of a sphere, there being no need for parallelism

I use autodesk's Revit program to get these measurements from a jpg.

The jpg is inserted to the drawing area then scaled to real world dimensions. The topo features of Revit allow you to recreate a 3d topo map. Sections can be cut though the new topo map and measured at will.

Check out this short video tutorial .

Revit topo tutorial

oh yeah, the drawing exports to all the usual formats. dwg, dxf, ...............

phoenix & Randall, many thanks for those conversion software links!

Just what the Doctor ordered....I needed them badly here.

We use a GIS mapping program, MapInfo from Pitney Bowes.

In that you can Open an image file. As you open it, you select the option to "Register" the image. This lets you select at least 3 points on the image & locate those same points on the map. The image is then overlayed at the correct scale into the map layers. It is still just an image, but you can measure points on the image using the MapInfo tools.

Similarly you can insert an image into AutoCAD, you just need to work out how to "scale" it correctly. I do not have this detail to hand at present, but others should be able to advise, or just read the AutoCAD Help files.

It will still be an image (not lines), but if it is scaled correctly when you import the image, then all dimensions taken should be accurate (up the the accuracy of the imported scale).

Hope this may be of some help.

Cheers

Tony