"Fitting" an aerial photo into a CAD drawing

[cdale]

Does anyone know if there is an EASY way to "fit" an aerial photo into a AutoCAD drawing?

I am using AutoCAD 2002 and have a pretty accurate drawing of a large site (~1 mile by 3/4 of a mile) that shows some buildings and roads in the area. I referenced in the image of an aerial photo because I want to underlay the map and be able to draw in some more features by tracing the photo.

I realize the photo has error in it and I know that is why I cannot just plop it into the drawing and have everyhting match up, so I am trying to figure out if there is a tool or method of stretching or rubbersheeting the photo??? I think there is a tool in ArcView that will do something like that but since I am using AutoCAD that doesn't really help...

Any ideas or knowlege would be much appreciated, thanks.

 

[IRstuff]

You can't stretch in Autocad? Must be just about the only program then. Have you tried to paste into Powerpoint or the like and scale and copy back?

If that doesn't work, there's IRFAN Viewer, which is free to try and has a resampling function that allows you to change the number of pixels in a picture.

TTFN

 

[MEM1]

Where did you get your aerial photo? Is the photo at some scale already? If so, you should be able to insert it into autocad and then rescale the photo there.

 

[JKinzenbaw]

You can rubbersheet the photo if you have CAD Overlay using 4 common points between the photo and your drawing. If you don't have Overlay then I would suggest scaling your photo somewhat close to what you drawing scale is and then use the "align" command (choose 3 common pts) to match the photo up.

 

[cdale]

IRstuff...you can stretch things in AutoCAD, but I don't think you can do it with an image. As far as I am aware, all you can do is straight scale the photo up or down, unless you have an AutoCAD add on program like "Raster Design"...thanks for the tip I will check out IRFAN...

MEM1...it is a photo we had flown...so if I understand you I think you are saying I can scale the image to whatever scale they flew it at? I will try it...

JKinzenbaw...I don't have CAD Overlay but I have heard other people talk about it, is it like Raster Design because I could not find anything about Overlay on Autodesk's website. That "align" command will be handy...

Thanks all...

 

[IRstuff]

In Autocad Lite, if you right click the image and select "Properties", it allow you to independently scale width and height.

TTFN

 

[MEM1]

I insert a lot of aerial photos from terraserver. These photos come in 1 meter resolution. Meaning each pixel is 1 meter by 1 meter of earth. From terraserver if you download a 1 meter photo, you end up with a photo 800 meters by 800 meters. A quick conversion to the units you are drawing, then just do an insert raster image from the insert menu, it should ask you for a scale. My scale is usually 1:~2640. Then its a mater of rotating and moving the photo until it is correctly positioned. It won't be exact, but you should be able to get close. On your photo, if you have a building or fence line that you surveyed, you can use that to adjust your scale. If you want, send me the file and photo and I will see what I can do.

murrisonenvironmental@cox.net

 

[JKinzenbaw]

cdale,

CAD Overlay is Raster Design, they changed the name in between v.2002 and v.2004 I think. Also I believe you can use the "align" command with any version of ACAD it's "rubbersheeting" images that you need Raster Design for. Just another tid-bit-- Raster Design is also handy with geo-referencing images to the coordinate system of your choice and exporting .tfw's to give your images known location.

 

[wp483]

Try AbleVector at

http://www.cadeast.com

please!

 

[sc]

You can stretch a photo in multiple directions, however if the site is that big then the need for an "exact" match diminishes.

I have overlain a 8km radius photo over the GPS data with reasonable accuracy. If the need for the match is to be fairly good then a ground survey is the best approach.

sc

 

[rawuser]

I don't know where you got your image from, but if you can get an image that has a tfw or jpw extension you can import it into your drawing and it will come into the drawing geospatially referenced and to scale. I used to have a lisp routine called tifin.lsp that would bring images in at the right coordinates and scale. That is what brought me here this evening. I am trying to find that lisp routine so I can import a quad sheet into a survey I have done...Any help out there?

 

[rawuser]

The gentleman above, mem1, mentioned one of my favorite sites, terraserver. they have the whole united states in aerial photo and quad sheets. Any of these can be exportes in a georeferenced state and imported directly into your drawings. Provided that is that you are using a state plane or world projection coordinate system. the key is the import lisp routine, tifin.lsp

 

[chicopee]

if your images are jpegs or tifs you can open them up in acad and scale them to actual sizes. if you know the real distance between two points(the longer the distance the better), then measuring those same distances in acad, you can calculate scale factors to be applied when you invoke the scale command. Redo the scale factor bit a couple more time to get better accuracy. I do it all the time with my digital images from my camera.