topic Re: Make NetCDF Raster Layer - grid is shifted in ArcGIS Pro Questions

Make NetCDF Raster Layer - grid is shifted

JayEdebeli — Thu, 01 Oct 2020 13:41:14 GMT

Hi,

I am having a problem where when I use the "Make NetCDF Raster Layers" tool to import netcdf files into ArcGIS pro, the grids are shifted by 0.01 deg. This problem causes my data to not align with each other. When I working with the output from ArcGIS else, the grids are not as expected.

Has anyone else experienced this problem? Is there something I can change in my import to prevent this shift?

Thanks for your help.

Re: Make NetCDF Raster Layer - grid is shifted

DanPatterson — Thu, 01 Oct 2020 15:56:56 GMT

Make NetCDF Raster Layer (Multidimension)—ArcGIS Pro | Documentation

What did you use for the cell registration parameter? would it make enough of a difference? (you don't quote cell size)

Re: Make NetCDF Raster Layer - grid is shifted

JayEdebeli — Fri, 02 Oct 2020 07:09:10 GMT

My cell size is 0.02 x 0.02 deg. Cell registration was centered; I used this for my different files covering the same area. One file however has a cell size of 0.1 x 0.1 and the second is the higher resolution.

Re: Make NetCDF Raster Layer - grid is shifted

DanPatterson — Fri, 02 Oct 2020 09:37:32 GMT

You will have to elaborate more. Are they all shifted? What are the extents of each? Are they misaligned when you are overlaying them or are they adjacent?

Do they have a defined coordinate system? If you used "center" alignment, does that jive with the extent? or would one of the other options be correct given the extent?

etcetera

Re: Make NetCDF Raster Layer - grid is shifted

JayEdebeli — Wed, 07 Oct 2020 08:34:51 GMT

Units outside arcGIS pro:

xunits = "degrees_east"

yunits = "degrees_north"

The extents for the 0.1 resolution file in wrf chem outside ArcGIS pro (original file with original extents of the raster):

xfirst = 0.05 (left)

xinc = 0.1 (delta x)

yfirst = -89.95 (top)

yinc = 0.1 (delta y)

The extents for the 0.02 resolution outside ArcGIS pro (file created in arcGIS from the 0.1 resolution file, cut to 48.07 top in arcGIS):

xfirst = 5.91 (left)

xinc = 0.0199999999999996 (delta x)

yfirst = 48.06 (top)

yinc = -0.0200000000000031 (delta y)

In arcGIS, both are imported using centered cell registration.

Units: dd

Coordinate system for both: WGS1984

Extents in ArcGIS for 0.1 resolution obtained from properties information:

Top: 89.999996

Bottom: -89.999996

Left: -0.000003

Right: 360.000015

Extents in ArcGIS for the 0.02 resolution obtained from properties information:

Top: 48.070000

Bottom: 45.570000

Left: 5.900000

Right: 10.600000

Due to this difference, when we overlay both rasters, they do not align on the vertical. If the vertical extent of the 0.02 resolution raster remained 48.07 as in arcGIS (this was created in ArcGIS), they would align in the external program. Also, if the 0.1 resolution raster remained -89.95 (top) when imported to arcGIS, the rasters would align also in arcGIS.

What I don't understand is why the extents (top especially) are different in and out of arcGIS.

Thank you for your help.

Re: Make NetCDF Raster Layer - grid is shifted

DanPatterson — Wed, 07 Oct 2020 09:17:24 GMT

quick solution

Shift (Data Management)—ArcGIS Pro | Documentation

This adds another dimension...

...they would align in the external program...

Re: Make NetCDF Raster Layer - grid is shifted

JayEdebeli — Wed, 07 Oct 2020 09:57:24 GMT

Thank you.