Global Mapper v25.0

Importing / rectifying a pdf map - rectangle appears as rhomboid

hover
hover Global Mapper UserTrusted User
edited April 2014 in Technical Support
I try to import this map: map-02Apr2014-2103.pdf, choosing the "manually rectify" option when prompted.

As projection I select Swiss Grid CH03, a projection with a base of 600000 / 200000.
In the zoom view, I then designate two reference points,
- Point 1: 608900 / 198300
- Point 2: 608850 / 198400
Both points are marked with a crosshair, as expected.

After importing, the rectangle "2292" on the map appears skewed (as a rhomboid) and the north indocator (on the map) doesn't point upwards.

What am I doing wrong?
I would have expected the map appearing rectified and rotated, in Global Mapper.

Comments

  • Mykle
    Mykle Global Mapper User Trusted User
    edited April 2014
    Hello Hover,

    Add Point 3: 608900 / 198400

    Two points are fine when you have a map that is already rotated, with equal x- and y-scales.

    Two points do not provide enough information to rotate an image and rectify it.

    For example, I used three points to import your map, then exported a JPG file.
    When importing the JPG (without separate world or projection file), I need to manually rectify the image.
    Using your two points is now sufficient and it overlays the original import nicely.

    Mykle
  • hover
    hover Global Mapper User Trusted User
    edited April 2014
    Hi Mykle

    A perfect hint, I really appreciate.
    Thanks a lot!