Hello:
[
EDITED]
An important consideration may be necessary when working with Global Mapper due to a change in behavior which was apparently implemented in more recent versions in that program.
It seems that Global Mapper (
sometimes) dynamically accepts and defaults to the internal projection settings of a GIS data file in order to import it and display it within the Global Mapper workspace ...
even if one has already set the default configuration of Global Mapper to be at "Projection: "
Geographic (Latitude / Longitude)", Datum: "
WGS84", Planar Units: "
ARC DEGREES".
So when one opens a GIS data file, it may by default be displayed in the same internal projection stored within that file.
To "force" the re-projection in Global Mapper to make the GIS source data display
and export in the format required when that data is to be exported for use with the FS SDK, one must
again reset the projection during the work session
immediately after one's first GIS data file is loaded ...via this procedure:
The correct configuration to set up in Global Mapper before opening a GIS data file or downloading GIS data ...and
AGAIN '
after' opening data files when that data is to be "Exported" for use with the FS SDK:
Global Mapper Menu > Tools > Configure... > [Projection Tab]
Projection: "
Geographic (Latitude / Longitude)"
Datum: "
WGS84"
Planar Units: "
ARC DEGREES"
Parameters:
Attribute: "
CENTRAL LONGITUDE"
Value: "
0"
BTW: As a visual clue that one has 'remembered" to re-project to WGS84 for
ex: FS SDK use, the Global Mapper workspace display of the GIS data should compress vertically and rotate counter-clockwise to some extent.
NOTE: Global Mapper is IMHO likely to yield more consistent results when the GIS file which one needs to re-project is the ONLY file loaded in a particular work session; thus it is preferable to
not attempt to use that file as one of multiple files which are being turned on and off in the "Control Center" within a work session.
If it is necessary to attempt isolation of a particular GIS file which one needs to re-project and/or export as the
ONLY "active" or visible file within a
multiple file layer work session, it may be likely to yield more consistent results when that GIS file is loaded
FIRST, re-projected, and
then load the other
multiple file layers afterwards.
[
END_EDIT]
Example settings in Global Mapper for export of elevation data
This configuration may work for certain source data file formats in Global Mapper
after downloading and opening a GIS
elevation data file ...when that data is to be exported for use with FS SDK Resample to output a terrain mesh BGL:
1.) Global Mapper Menu > File > Export > Export Elevation Grid Format...
2.) At 'Select Export Format' prompt, choose "GeoTIFF" from the pick list
3.) In 'GeoTIFF Export dialog, on [
GeoTIFF options] tab:
File Type: "
Elevation (16-bit integer or 32-bit floating point) samples (=Radio Button 'Ticked')
Vertical Units: "
Meters"
Resampling: "
Bicubic Interpolation"
Sample Spacing / Scale: (
disregard =Automatically filled in by Global Mapper)
Always Generate Square Pixels:
(=Checked)
Always Export At The Fixed Scale 1: "
0"
(=Not-Checked)
DPI Value To Save in Image (0 for None): "
0"
(=Not-Checked)
Compression:
Default (No Compression)
ADVANCED: Use Tile Rather than Strip Orientation:
(=Not-Checked)
ADVANCED: JPEG-in-TIFF Quality: "
75" (
disregard =Automatically filled in by Global Mapper)
Interpolate to Fill Small Gaps in Data:
(=Checked)
Generate TFW (World) File:
(=Checked)
Generate PRJ File:
(=Checked)
Generate OziExplorer .map File:
(=Not-Checked)
ADVANCED: Don't Write GeoTIFF Header:
(=Not-Checked)
4.) In 'GeoTIFF Export dialog, on [
Tiling] tab:
No Tiling - Just One Export File:
(=Radio Button 'Ticked')
Skip Existing Files (Use to Complete Cancelled Exports):
(=Not-Checked)
5.) In 'GeoTIFF Export dialog, on [
Export Bounds] tab:
All Loaded Data:
(=Radio Button 'Ticked')
...or:
Click "[
Draw a Box...]" button and select desired area from displayed workspace (or specify otherwise via the GUI in that dialog box Tab)
Hope this detail helps with your project !
GaryGB