Global Mapper v24.0

Image that Crosses International Dateline - mirrored - stretched

maxsquires
maxsquires Global Mapper User
edited July 2008 in Projection Questions
Hello.

I am wondering if there is a problem with the reading of data that crosses the international dateline.

I am working with a Mercator projected raster image (I can supply it to you via email, but it can also be found by the following method)

visit

Office of Coast Survey - NOAA Raster Navigational Charts

agree to the statements by pressing the "Proceed to NOAA RNC? (BSB) Downloads" button.

press the ~"textual" button

on the following screen select the dropdown toggle that allows you to display more charts on the page.

select "1019"

"CTRL F":
"BERING SEA SOUTHERN PART"
select the check box next to it
scroll up to top of page and press the "Review Selections>>" button.

on the following screen press the "Order Selections" button.

wait a few moments,

then download the NOAA_BSBs#########.zip file

The kap file 513.kap, when added to the map dispaly is drawn stretched out to both extents of the map and mirror-imaged.

There are a couple of NOAA Charts that span the dateline in this way and I would love to be able to work with them.

Thanks for your help.

Max

Comments

  • global_mapper
    global_mapper Administrator
    edited July 2008
    Max,

    The problem was that the Mercator projection defined in the chart didnt' specify a central meridian, so 0 was used, which of course does not cross the ATM, hence the strange display of the chart. I have now updated Global Mapper to detect this situation and use a projection with a central meridian at the ATM, which fixes the problem.

    I have placed a new build at http://www.globalmapper.com/global_mapper9.zip with the change for you to try. Simply download that file and extract the contents into your existing v9.xx installation folder to give it a try.

    Let me know if I can be of further assistance.

    Thanks,

    Mike
    Global Mapper Support
    support@globalmapper.com
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