Rectify/Projection

Kusnandar

Hi

I am trying to rectify an image from google earth that i have created. When i try to rectify using manualy rectify with selection projection of UTM-55/GDA94GDA. When I add GCP I got the Lat and Long value BADCOORD. could you help me with this problem.

I attached the image that I would like rectify.

Thank you
Kusnandar

global_mapper

Are you entering your coordinates as lat/lon values or UTM values? Also, make sure to select zone 55 in the Southern Hemisphere and not zone 55 in the Northern Hemisphere.

If you still have trouble, can you provide a screenshot with the control points?

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

Kusnandar

Thank you Mike.

This is the steps when I tried to used image rectify:
I open the image from File, open then then image rectifie window pop up, then I change the Ground Control Point Projection to UTM-55/94GDA

After that when I placed the first GCP point on Zoomed View(click for pixel coordinates). I got the massage pop up: say" The projected coordinate values that you entered appear to be latitude/longitude coordinates. are the coordinate lat/long coordinates or are they in the selected projection system?
Yes- Lat/Lon coordinates (they will be automatically converted for you)
No- Coordinates are in the selected projection" so in this case I choose No because I change the Projection to UTM-55/94GDA/meter.

then the image rectifier comes BAD COORDINATE see file attachement.

the biggest problem is I don't know how to add more GCP on the image rectifier? could you please show me how? I have had followed manual instructions always fail. thays why I asked you is there any video to show how to use image rectifier

Thank you Mike.

Regards,
Kus

global_mapper

Kusnadar,

It looks like you are not entering any ground coordinates to go with your selected pixel coordinates when rectifying the image. You need to select a pixel location, which it appears that you have done, then enter an associated ground location, in UTM-55/GDA94 in your case, then press the "Add GCP to List" button. So you need to know the easting/northing values in UTM associated with your pixel location, or else enter lat/lon values if you know those. You have to have both pixel and ground coordinates for multiple locations in order to establish a mapping between pixel and ground coordinates.

To add more points, just enter/select new pixel and ground coordinaets, then press the Add GCP to List button again. Repeat for additional points.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

Kusnandar

Hi Mike,

Thank you very much for your explanation.

If I don't know easting/norting values the image rectify can not be done. It seem that I don't know the easting/norting values. Is there any quick way to find easting/northing values?

Kusnandar
just started to used global mapper

global_mapper

Kusnadar,

You should be able to see either lat/lon or easting/northing values in Google Earth as you move your cursor over the data. You could then write down those values and enter them in Global Mapper.

Have you tried using the File->Download Online Imagery menu command in Global Mapper and pulling in the Digital Globe imagery for your area of interest? In many cases you will get data similar to what you get in Google Earth.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

Kusnandar

Hi Mike,

Thank you very much for your quick reply and help.

I can use imagery rectify now.

Cheers