Projected Exported JPG on an Angle (Beginner Question)
tburke
Global Mapper User
Note: Please bear with me I'm not a GIS tech by trade (engineer and have had to teach myself this) so I'm assuming the answer is a simple mistake on my part. Also not certain if this is a projection question or geo-refencing question.
I'm am attempting to create a geo-referenced raster (jpg) that will be used in a simple 2-D x-y grid (with every individual point being a calculated GPS point). I'll be given an unrectified image that appears to be straight overhead and will use either Google Earth (unfortunately ground survey points are not an option) to reference the image since the end result must have points that correspond to Google.
Unfortunately, when I do export the image, the result seems to be at a significant angle (say 15-25 degrees off of straight overhead/90 degrees). When I test the accuracy of my image it is GPS accurate relative to Google in my x-y grid. Also, as a test, I exported an image direct from Google Earth and using the same procedure it was also GPS accurate but with a straight overhead view.
There is something I am missing in this process that is leading to this skewed image (possibly something very basic). Any help would be much appreciated.
Projection Used = Geographic (but have also tried Plate Carree)
Datum Used = WGS84 (but have also tried NAD83 upon a suggestion from elsewhere)
Angle of Original Image = Typically no worse than 5-8 degree from the 90 degree
I'm am attempting to create a geo-referenced raster (jpg) that will be used in a simple 2-D x-y grid (with every individual point being a calculated GPS point). I'll be given an unrectified image that appears to be straight overhead and will use either Google Earth (unfortunately ground survey points are not an option) to reference the image since the end result must have points that correspond to Google.
Unfortunately, when I do export the image, the result seems to be at a significant angle (say 15-25 degrees off of straight overhead/90 degrees). When I test the accuracy of my image it is GPS accurate relative to Google in my x-y grid. Also, as a test, I exported an image direct from Google Earth and using the same procedure it was also GPS accurate but with a straight overhead view.
There is something I am missing in this process that is leading to this skewed image (possibly something very basic). Any help would be much appreciated.
Projection Used = Geographic (but have also tried Plate Carree)
Datum Used = WGS84 (but have also tried NAD83 upon a suggestion from elsewhere)
Angle of Original Image = Typically no worse than 5-8 degree from the 90 degree
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