uDIG

Zoom Tool Accuracy

Details

  • Type: Bug Bug
  • Status: Resolved Resolved
  • Priority: Minor Minor
  • Resolution: Fixed
  • Affects Version/s: UDIG 1.3.0
  • Fix Version/s: UDIG 1.4.x
  • Component/s: tools and editing
  • Labels:
    None
  • Environment:
    All

Description

When zooming in using the zoom tool the extent you get isn't what you've drawn a box around. That is, drawing a box around an area retuns a zoomed in view of part of it. See attached screen shots for two examples.

Steps to reproduce:
1. Load up the initial countries dataset from the natural earth data_1_3.zip bundle
2. zoom to extent
3. Use the zoom tool to draw a box around australia (with the center of the box in the middle of australia)
4. Notice the result shows australia 1/2 off the screen to the eastward direction

If you zoom to a place on the westward side greenwhich it is inaccurate in a westward direction.

  1. Zoom result.jpg
    208 kB
    17/Oct/11 1:48 AM
  2. Zoom result (2).jpg
    133 kB
    17/Oct/11 1:48 AM
  3. Zoom selection.jpg
    177 kB
    17/Oct/11 1:48 AM
  4. Zoom selection (2).jpg
    178 kB
    17/Oct/11 1:48 AM

Activity

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Brett Hollindale added a comment -
Check out the screen shots in this order: Zoom selection, Zoom result, Zoom selection (2), Zoom result (2)
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Brett Hollindale added a comment - Check out the screen shots in this order: Zoom selection, Zoom result, Zoom selection (2), Zoom result (2)
Jody Garnett made changes -
Field Original Value New Value
Summary Zoom tool issue Zoom Tool Accuracy
Priority Major [ 3 ] Minor [ 4 ]
Description When zooming in using the zoom tool the extent you get isn't what you've drawn a box around. That is, drawing a box around an area retuns a zoomed in view of part of it. See attached screen shots for two examples. When zooming in using the zoom tool the extent you get isn't what you've drawn a box around. That is, drawing a box around an area retuns a zoomed in view of part of it. See attached screen shots for two examples.
----
Steps to reproduce:
1. Load up the initial countries dataset from the natural earth data_1_3.zip bundle
2. zoom to extent
3. Use the zoom tool to draw a box around australia (with the center of the box in the middle of australia)
4. Notice the result shows australia 1/2 off the screen to the eastward direction

If you zoom to a place on the westward side greenwhich it is inaccurate in a westward direction.
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Jody Garnett added a comment -
Notes from testing in debugger:
- the new palette code is not responsible (changes to the palette do result in a change to the map bounds used to determine the aspect ratio; and zoom center). So the obvious source of a change is accounted for.
- the code looks very straight forward - it finds the new center; and then uses the ratio of widths to determine a "zoom factor". Both of these are used to calculate the new viewportbounds.

Q: Is the "center" determined in screen coordinates (ie pixles) or in world coordinates - perhaps the curvature of the earth is getting us here?
A: not sure
Show
Jody Garnett added a comment - Notes from testing in debugger: - the new palette code is not responsible (changes to the palette do result in a change to the map bounds used to determine the aspect ratio; and zoom center). So the obvious source of a change is accounted for. - the code looks very straight forward - it finds the new center; and then uses the ratio of widths to determine a "zoom factor". Both of these are used to calculate the new viewportbounds. Q: Is the "center" determined in screen coordinates (ie pixles) or in world coordinates - perhaps the curvature of the earth is getting us here? A: not sure
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Jody Garnett added a comment -
Q&A with Jesse:

Q: Are zoom and pans correct?
A: "yes"

Zoom with scroll wheel is perfect
Zoom with single click (left to zoom in, right to zoom out) is perfect; but the amount it zooms by is very very small and no longer useful
Pans using pan tool are correct

(from this we can assume the transform and commands are correctly working)

Q: Is it worth holding up the uDig 1.2.3 release for this?
A: Because zoom and pan are working the software is still functional. We will release a patch as soon as a fix is ready
Show
Jody Garnett added a comment - Q&A with Jesse: Q: Are zoom and pans correct? A: "yes" Zoom with scroll wheel is perfect Zoom with single click (left to zoom in, right to zoom out) is perfect; but the amount it zooms by is very very small and no longer useful Pans using pan tool are correct (from this we can assume the transform and commands are correctly working) Q: Is it worth holding up the uDig 1.2.3 release for this? A: Because zoom and pan are working the software is still functional. We will release a patch as soon as a fix is ready
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Silvia Franceschi added a comment -
I have this problem too and I guess that it is not due to the new palette because there is the same problem in the 1.2.2.
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Silvia Franceschi added a comment - I have this problem too and I guess that it is not due to the new palette because there is the same problem in the 1.2.2.
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Andrea Antonello added a comment -
This has been solved in: master 12927ae

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Andrea Antonello added a comment - This has been solved in: master 12927ae
Andrea Antonello made changes -
Status Open [ 1 ] Resolved [ 5 ]
Assignee Andrea Antonello [ moovida ]
Fix Version/s UDIG 1.3.x [ 17102 ]
Resolution Fixed [ 1 ]

People

  • Assignee:
    Andrea Antonello
    Reporter:
    Brett Hollindale
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Dates

  • Created:
    Updated:
    Resolved: