Place straightening points in a deliberate order so each adjustment corrects a large part of the chart before you work on smaller problem areas.

This guide continues from Straighten Chart. Before placing any points, make sure the corners and row and column counts are correct, then align the thick overlay lines with the chart's thick printed lines.

Work from broad corrections to local ones. Adjust the outer edges first, then the centre lines, and finish by checking each quadrant. This usually reduces the number of points you need to move.

1. Straighten the Outer Edges

Top and Bottom Edges

Move from left to right across the top edge, then repeat across the bottom edge.

Aligning points along the top and bottom helps straighten the chart's vertical grid lines across its full height.

Left and Right Edges

Move from top to bottom along the left edge, then repeat along the right edge.

Aligning points along the left and right helps straighten the chart's horizontal grid lines across its full width.

2. Correct the Centre Lines

Work Through the Middle

Work across the horizontal centre, then down the vertical centre.

These two passes correct distortion through the middle of the page and divide the remaining work into four smaller areas.

3. Refine Each Quadrant

Finish the Remaining Problem Areas

Check each quadrant and adjust only the points that still miss the printed intersections.

Most of the grid should already be close. Work through the four areas in any consistent order, concentrating on corners, book folds and other local bends.

For a sharp local bend: Switch to the x5 layout for more control, then add points only around the affected area. Recheck the thick-line alignment before continuing because changing the spacing or offsets resets placed points.

[Screenshot: a real chart after the outer edges and centre lines have been aligned, ready for quadrant refinement]

Apply and Review

  1. Choose Apply to straighten the image using the points you placed.
  2. Inspect the entire grid, not only the area you adjusted.
  3. If necessary, add or move a few points in the remaining problem areas and choose Apply again.
  4. Use Undo and Redo to compare applied versions before you finish.

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