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Changing the scale on a vector image when exporting

This article relates to Scan2CAD v9.

Scan2CAD has an advanced option for scaling the currently loaded vectors when exporting them to a vector file such as DXF.
To scale the export vectors use the following menu option.
File Menu > Vector > Scale Options…

The following dialogue will be displayed:

Vector scale options

The dialogue contains 3 scaling methods namely:-

  1. DPI
  2. Distance
  3. Geo

We will go through each option below.

1. Scale using DPI

Click on the ‘DPI’ Scaling method.
If the value in the DPI field is 0, enter the DPI resolution that you scanned the drawing at. (If your raster image contains DPI information a value will be inserted here automatically.) Now enter the scale of the original paper drawing that you scanned in.
For example:
If the drawing was at 1:1 enter the scale like this:

Setting image DPI

If the drawing was at 1:50 enter the scale like this:

Setting Image DPI For 1:50 scale

If the drawing was at 1″ = 1’ enter the scale like this:

Setting Image DPI Example 3

If the drawing was at 1/8″ = 1’ enter the scale like this:

Setting image DPI example 4

2. Scale using Distance

Click on the ‘Distance’ Scaling method. Then, click the ‘Measure’ button.

You should now be returned to your drawing. Position the mouse pointer at the start of the reference point (raster line or vector line) – press the left mouse button and drag the mouse pointer to the end of the reference point – release the mouse button.

Setting scale by measuring the distance

You will now be returned to the scaling dialog.

The scaling dialogue

The ‘Image Pixels Distance’ field will now contain a value of pixels between the start and end point of the reference line (958.0..).

As an example I will have that distance represented as 5 feet in the exported vector file.

In the ‘Vector Units Distance’ field type the distance between the start and end point of the reference line (I have inserted 5.0 as an example)

Select whatever Units the Vector Units Distance represents in the Unit selector (I have selected Feet).

Set the ‘Tie Point’ fields to zero (as illustrated above)

Set the ‘Scale Factor’ fields to 1 (as illustrated above)

Set the ‘Export Units’ to ‘Feet’ (as illustrated above)

Press OK.

3. Scale using Geo

Click on the Geo Scaling Method.

Calculate the distance that each pixel in the raster image represents in the X and Y directions.

Enter these figures into the Geo Pixel Scale X and Y boxes (the X and Y scaling factors will usually be the same).

For example, if 1 inch on a map you have scanned represents 100 inches on the ground in the X (horizontal) direction, and you scanned the map at a resolution of 300 dpi (dots per inch), then the distance represented by each pixel in the horizontal direction will be 100 / 300 = 0.3333333.

Exporting your file

The above export option settings will be applied to the exported vectors when saved using the file Save As.. option as follows.

File Menu > Vector > Save As..
When prompted ‘Do you wish to set scaling options’ respond Yes
(This will display the above dialog confirming the previously applied scaling.) Now press OK and the DXF file will be saved.

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