Global Mapper v25.0

Adjust/Rectify Raster/Work spaceto the Grid

smile
smile Global Mapper UserTrusted User
edited July 2008 in Suggestion Box
Again this suggestion may be Utopian but it will help us save a lot of time and add functionality to the Global Mapper

However accurate may be one's calibration for each raster , when we load multiple scanned paper maps after calibration and enable the lat/lon grid , the cumulation of one's errors or due to sheer limitation of human readability we find a minor shift of workspace rasters from the grid say about 20 mtrs.

If it is possible to adjust the workspace to the grid in one go (to a limit), this will save hours of manually adding innumerable Gcps

Further , I find in the rectification window reference map on extreme right does not auto sync move with middle map, if it can auto sync,manual addition of GCps from ref map would be faster , as it takes a lot of time to locate the points in the absence of auto sync

Thanks

Smile

P.S: The Grid is the Acid test for any manual rectification and transformation, if it can also help correct the errors...

P.P.S: Similarly, if we can open a Raster at a fixed location by defining all four bounds and still zoom in /zoom out like a normal data file will also be helpful to correct certain rasters

Thanks

Smile

Comments

  • global_mapper
    global_mapper Administrator
    edited September 2007
    You can easily shift a layer by some fixed amount. To do this, simply open the Overlay Control Center, right-click on the layer, select the Reposition option, then use the option to shift all control points to provide your desired shift amount, then press OK.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • smile
    smile Global Mapper User Trusted User
    edited September 2007
    Yes. That is the rectification window. I requested about sync of the ref window.

    I was actually thinking on the lines of some kind of a visual drag on the main window to match the grid or the program to sense the diffrence in Grid and the workspace as a whole a the rectfication window can handle only one raster at a time ( of course one can export to single ecw or jpg .but that gives a world file with just two points and not much control is possible with those two points and the pixel/mtr info along with it)

    To some extent Auto Sync and able to view work space as whole can help a lot

    Thanks

    Smile
  • global_mapper
    global_mapper Administrator
    edited September 2007
    For sync'ing the Reference Window with the Zoomed View window, if you hold down the CTRL key when left clicking in the Zoomed View, it will automatically pan the Reference Window to the same approximate location (if possible).

    We may add support for dragging and shifting one or more layers at a time in a future release.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • smile
    smile Global Mapper User Trusted User
    edited September 2007
    Yes. The Auto Sync works fine with control key on all three windows except that Zoom Window and ref window will sync at their current zoom levels only and Zoom sync may have to be added.

    In the meantime , can I request/suggest for "Generate GCPs" menu say 9 or 12 or more from a loaded single raster with world file . These GCPs will be useful for actually fine tuning the calibration ( for example a workspace of say 25 rasters has been made into a single ECW and we find that it requires a minor fine tuning due to cumulation of errors manual or otherwise). What One can do is Generate 12 or 24 GCPs , go to rectification window and import GCPS and then do the minor fine tuning ).

    I feel this may help until the visual drag or similar feature becomes available. I always wonder how professional outputs like vectors keep high precision accuracies, may be it goes through no of iterations, time and manpower

    Thanks

    Smile
  • global_mapper
    global_mapper Administrator
    edited September 2007
    I'll consider adding some functionality like that in a future release.

    Just a tip, if you are rectifying and you know the original source projection (or something close) of the layer that you are rectifying, it is very helpful to use the Projection button on the rectification dialog to change the native projection of the layer to match that original source projection. If entering control points as lat/lon, this is usually the last step that you would do before pressing OK so that your control points can be reprojected. If you can match the original projection you can even get a perfect representation with just 2 control points.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
  • willi
    willi Global Mapper User
    edited July 2008
    Hi globalmappers,

    yes synchronization may work using control key, but it does not (and can't) work, if still no GCPs have been defined so far
    Therefore: looking for the FIRST or second GCP-reference in the reference window by doing a zoom-functionality (holding mouse key and dragging a zoom area within the reference window) may take me into a zoomed status, possibly in a very wrong place. From this status/point of view no way back is possible?
    I would prefer to hav a zoom-slider beside every one of the three windows inside recitfier.
  • global_mapper
    global_mapper Administrator
    edited July 2008
    You can right click in a zoomed in window to zoom back out. You can also draw a new box on the far left map display to change the view of the middle map display.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com