Georeferencing images for use with PolarView
Georeferencing images for use with PolarView
April 19, 2012 01:12PM
PolarView supports import of images in PNG or JPG format to be displayed as chart overlay.

To import an image:
- Open Image Manager by using menu File: Image Manager or keyboard shortcut Ctrl + B (Windows) or Cmd + B (MacOS)
- Press Add button
- In file dialog select image file and press OK
- Reference Points dialog will appear prompting you to enter coordinates of at least 4 points in the image with their corresponding latitude and longitude.
- Enter 4 or more reference points values and press OK.
INFO Image pixel coordinates are from the top left of the image.
WARNING You must provide at least 4 reference points, located in different parts of the image. Image must be either in Mercator projection or covering sufficiently small area to reduce georeferencing errors.

To avoid manual reference point entry, you can also provide reference points in an XML file which will be loaded together with the image.

Reference XML file should be located in the same directory as the image and have the same file name, and extension .xml. I.e.:
MyImage.png
MyImage.xml

XML file should include a single ref tag that encloses 4 or more refp tags, one per each reference point. refp tag must have the following attributes:
x - X axis image space coordinate, origin at top left, counted to the right
y - Y axis image space coordinate, origin at top left, counted downward
lat - latitude, decimal degrees
lon - longitude, decimal degrees

Example:

<ref>
<refp x="1000" y="2000" lat="35.50000" lon="-75.00000" />
....
</ref>

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Polar Navy Support



Edited 2 time(s). Last edit at 04/24/2012 01:14AM by Polar Navy Support.
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