1. Is it better to scan microfilm or the original
This depends on several factors:
- Which is in the better condition?
- Has the original plan been modified since being
- Aperture cards are normally scanned to a standard size,
e.g. A1. Hard copy drawings are scanned to their exact original size.
If they are both in the same condition, scanning the aperture
card is better.
2. After the microfilm or plans are scanned, what do I
You will be supplied with a raster (image) file.
3. What is a raster file?
A raster file looks like a series of lines but is, in fact, a series of
dots close enough to appear as smooth lines.
4. Can I modify the raster file in AutoCAD?
A major breakthrough is available in AutoCAD R14 with regards to raster
files. The following is a description down-loaded from Autodesk’s
Scan paper drawings into AutoCAD
"Now, for the first time in AutoCAD, you can display and plot raster
images – like scanned drawings and colour photographs – in
AutoCAD software as a standard selection, just like vector drawings.
Combine raster images with AutoCAD vector graphics to create hybrid
drawings, control the order in which they display, tailor the images,
and improve performance. These tools save time by letting you use
existing paper drawings, like as-built drawings of older structures or
mark-ups, in AutoCAD without having to redraw them."
5. What is vectorisation?
Vectorisation is the conversion of raster files to vector files. This
involves converting the series of dots to lines. The programs that do
this conversion currently achieve 80% success. The resulting vector
file would need to be cleaned up. The amount of clean up depends on the
quality of the original drawing. Text does not convert well if it is
hand written on the original. Despite these difficulties, it is
generally quicker and far less expensive to use this process than to
6. Can you vectorise the scans for me?
We offer a service to convert your raster images to vector files. The
final clean-up can be done on your own CAD system, or ours. Our
CADPerfect solution provides a drawing that is indistinguishable from
one drawn from scratch in a CAD program.
7. What resolution should I scan at?
The most commonly used resolutions range from 200 to 400 dpi. More
detail is picked up at higher scanning resolutions, but the cost in
file storage is also higher. Do not, therefore, automatically choose
the highest resolution every time. We use 300 dpi for line drawings.
8. What size are the files?
The higher the resolution, the larger the image file and the increase
is exponential. An A0 scanned at 300 dpi would be approximately 400 Kb.
The same drawing scanned at 400 dpi would be 800 Kb.
9. Can I view these files?
Utilities are available to view and print the images. The cost can vary
greatly depending on the complexity of the program you require.
10. Can I plot these files?
The utilities mentioned in the previous paragraph can also plot.
11. How can I store these files?
Many storage technologies are available today. Your choice will depend
on your requirements. The best solution could perhaps be a combination
of technologies. For example, On-line images are stored on a large hard
disk and the images are also backed up onto CD