Image Rectification

NakelaNakela Posts: 4
Hi there,

I am rectifying a Google Earth image in Global Mapper v18. I add in my Ground Control Points and then my image, and proceed to matching up the points. When I save the rectified image as a GeoTiff however and open it in ArcMap v10.4.1, the following notification pops up:

"One or more of the added layers has an extent that is not consistent with the associated spatial reference information. 

Re-projecting the data in such a layer may lead to unexpected behavior. Use ArcCatalog to confirm the spatial reference is correct and adjust if necessary."

When I open up the layer properties of the GeoTiff in Arcmap, it seems as though the extent of the raster has changed during the export. The extent of the top, bottom, left and right are in the thousands, instead of between -180 to 180 (longitude) and -90 to 90 (latitude).

How I can correct this? Please help.

Thanks. 

Best Answer

Answers

  • BillBBillB Global Mapper User Posts: 102Trusted User
    Hi Nakela
    I can't really help with you question about rectified imagery, but I was wondering why you were rectifying GE imagery in the first place?  Can't you just load Google Maps Imagery via File > Download online maps imagery?
  • NakelaNakela Posts: 4
    HI Bill,
    Thanks for your response.
    My company requires us to rectify a GE image of our study area for use in ArcMap, where we use the image as the base map. 

    If there is a way to download up to date GE imagery though on Global Mapper and export this to ArcMap, that would be great. 
  • NakelaNakela Posts: 4
    Thanks for the detail.
    Unfortunately I have no option on my Global Mapper to download Google Maps imagery.
    But no worries, I will continue to use image rectification. 

    Thanks for the help!! 
  • Amanda McDermottAmanda McDermott Global Mapper User Posts: 59Trusted User
    Hi Nakela,

    You certainly should be able to download google earth imagery within the program. I remember we had a similar issue with a new version of globalmapper once, where the online imagery we were used to using seemed to have disappeared - we had to re-link to it.

    I think you will find the answers in this thread: https://www.globalmapperforum.com/discussion/9768/bing-maps-aerial-photo-data - particularly the .xml file posted by the administrator J|an 2014. If you save the file, and then 'add sources from file' in the 'download online imagery' dialogue box, I think that might be the answer. Hope that helps!


  • sphillipssphillips Posts: 93
    Maybe you need to re-check that your ground control points are using the same projection as you specified in the Image Rectifier window (via Select Projection ... - see below). For example, the default projection is Geographic (Lat/Long) and that requires Long/Lat inputs as opposed to X/Y values in thousands.

    As Nakela mentioned you can download the xml file from the link above and add Google Earth and Bing to your download sources if you don't already have it.

    If you are also using ArcMap you might want to look into 'Portable Basemap Server'. Basically it's a way to add multiple online sources including Google Earth to your basemaps.




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