script height export

LPlateAndy

Hi Mike,

When exporting height data, i want to ensure we provide the values of the raw data as it's important to our customers to avoid any unneccessary interpolation.

I note the option "Export: Snap Export Bounds to Nearest Spacing Boundary" but i don't think i can see this in the script options.

Also, i thought i could cheat and for a 5m dataset made the co-ordinates in my required area snap horizontally to the 5m grid. However, i found that the xyz points output were aligned to 0,0 - 5,0 - etc whilst the raw data (originally a grid format) came out at 2.5,2.5 - 7.5,2.5 - etc

Have i missed something!

Thanks

Andy

global_mapper

Andy,

Rather than trying to align the data you could instead add SAMPLING_METHOD="NEAREST_NEIGHBOR" to the EXPORT_ELEVATION command and force all input elevations to be used when no interpolation.

For the alignment, your bounds for elevation exports are for the corners of the grid cells, while the actual samples will be at the center. So if you want the samples at even 5 meter intervals the corners would be 2.5 meters above and left of that.

Thanks,

Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation

LPlateAndy

Hi Mike,

OK - my misunderstanding.

Just to check - "NEAREST_NEIGHBOUR" does use the x,y and z of the source data? I'd assumed it left the same grid horizontally but applied the height of the nearest point.

Andy

global_mapper

Andy,

The resampling applies to how the Z values are resampled, the XY values are determined still by the bounding box provided and the sample spacing. Nearest neighbor just means that the Z value of the nearest cell center will be used rather than an interpolated value.

Thanks,

Mike
Global Mapper Guru
geohelp@bluemarblegeo.com
Blue Marble Geographics for Coordinate Conversion, Image Reprojection and Vector Translation