Image rectifier bug?

tim53

Hi:

I'm trying to convert pgm and tiff files to jp2's (or any other format with lat/lon/projection information for injesting into ArcMap) using global mapper 11.

I'm working with several Mars mosaics that are 35565 x 17782 pixels (30x60 degrees equirectangular). Many of them, I can simply open the image rectifier and input the latitude and longitude in the Ground Control Point Entry window, click "OK" and save as jp2's, and have them place accurately in my Arcmap file. But several of them give me a result like this (attached screenshot), where the values I've input for lon and lat are placed in the "projected x & y" columns, and the "longitude & latitude" columns always show 0° 04' 0.000" E & 0° 00' 30.0000" S. If there's a way to edit these columns, I haven't found it.

Suggestions?

-Tim.

global_mapper

Tim,

The latitude and longitude columns are calculated based on the input coordinate projected X/Y and the selected projection. What do you have selected for the projection (I can't see all of it in the screenshot, only that it's Geographic)? Based on the lat/lon values showing up it looks like you have arc seconds selected for the units, is that correct?

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

tim53

Mike:

I just noticed that the attachment can be pretty large, so here's a full screenshot of the file.

I let the projection default to Geogrpahic lat/lon/WGS84/arc seconds. I *think* that's what I've done for all the files that "worked" as well, but let me check after I post this, by reopening one of those files.

-Tim.

tim53

This file worked fine, and has the same settings.

-Tim.

global_mapper

Tim,

Global Mapper is doing the proper conversion for turning arc second coordinates (which is what you appear to be correctly using) into degree values (just divide by 3600). In your first problem example your second control point lists arc second coordinate of 240,30, which translates into something very near 0,0 in degrees (the displayed values for latitude and longitude are correct). Are you sure the 240 and 30 values are arc second values?

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

tim53

Actually, they're degree values. Should I multiply those by 3600 and try again? I didn't have to do that for the ones I successfully rectified, though.

-Tim.

tim53

Maybe never mind! I changed the projection to "arc degrees" and it appears to have worked. If I don't post back, it means I successfully loaded the file in Arcmap and had it place correctly!

-Tim.