streched maps with Geographical Coordinates

[global_mapper]

Actually reading your original post again I don't think the stretching you are seeing is due to the large binary grid issue, especially since your grid is less than 2GB in size.

I think what you need to do is load the data, then change the view/export projection on the Projection tab of the Configuration dialog to something like UTM. Also, are you being prompted to select a projection for the data when loading it? If so, it is critical that you select the proper projection for the data otherwise it won't be able to reproject properly. I'm guessing the native projection is Geographic (lat/lon) or perhaps Mercator if it is stretched longitudinally.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[fluvial]

The suggestion you made I did try - see my original post - changing to UTM did not fix it. The native projection of the DEM files is Transverse Mercator (this is the projection they are in when I first load them). I am not prompted for a projection when I load. I load other files on the same screen, shapefiles of attributes related to the same area, and they all appear correctly - but the DEM is stretched downwards over the screen, with the top edge seemingly in the right place. Note that the DEM was delivered as a zipped file, with 19 x 1.8 GB .adf files that make up the mosaic. These are 2 m Lidar grids covering a very large area in total. Loading all or one at a time makes no difference to the problem. Also, only one file appears as a "commonly supported type" - but the others load the same way by selecting Arc/Info Binary Grid.

[global_mapper]

Ah, so the data is latitudinally stretched, not longitudinally stretched. If so then the large Arc Grid issue is the likely problem as that is a symptom of that problem.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[fluvial]

Sorry - I did mistakenly say longitudinal stretch - I will upgrade to v11 and see if this solves it. On a separate matter, is there a way of drawing a transect line across an image that has a DEM, and various polygons with attributes (representing vegetation types for example), and saving a xyz file that also has attributes asociated with each point across the transect? If not elevation and attributes combined, can this be done for attributes only, in which case I could then combine later with an xyz file for the same transect. I am trying to do a vegetation transect across a floodplain, with the vegetation types associated with elevations.

[global_mapper]

What you could do for the transect is to create the line, then select it with the Digitizer Tool, right-click, then select the Advanced Feature Creation option to create regularly spaced point features along the line. Once those points are created, select them, then right-click and select to add attributes to the points from the area features that they are in and also to add elevation attributes from loaded terrain data. Finally, you can export those points to a CSV file to get a file with the XYZ coordinates plus any attributes from the polygons that the transect went through.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com

[fluvial]

Dear Mike
I can report total satisfaction with your suggestions. v11 fixed the problem with the stretched images, and your suggestion for creating a transect with attributes is also a winner. Many thanks - I can now get on with my work in a more productive fashion.

[fluvial]

Mike - if you could help me with one last thing - once I have created the transect line with the attributes associated, how do I export it as a csv file?

[global_mapper]

Once you have created the points from the transect line and gotten the attributes added to them, simply use the File->Export Vector->Export CSV menu command to export the data to a new CSV file.

Let me know if I can be of further assistance.

Thanks,

Mike
Global Mapper Support
support@globalmapper.com