grid_load.m doesn't support reading ECCO-GRID.nc in ECCO v4r4

[LLLavinia]

I'm interested in this issue. To try to understand it better, I looked at the diff between the ncdump of Release3/nctiles_grid/GRID.0001.nc and Release4/nctiles_grid/ECCO-GRID_00.nc. Is this the right comparison to be making? The results are below

1c1

< netcdf ECCO-GRID_00 {

---

netcdf GRID.0001 {

3,10c3,6

< 	k_p1 = 51 ;

< 	j_g = 90 ;

< 	i_g = 90 ;

< 	k = 50 ;

< 	j = 90 ;

< 	k_u = 50 ;

< 	i = 90 ;

< 	k_l = 50 ;

---

	itxt = 30 ;

	i1 = 50 ;

	i2 = 90 ;

	i3 = 90 ;

12,53c8,26

< 	int64 k_p1(k_p1) ;

< 		k_p1:long_name = "z-dimension of the w grid" ;

< 		k_p1:swap_dim = "Zp1" ;

< 		k_p1:c_grid_axis_shift = -0.5, 0.5 ;

< 		k_p1:axis = "Z" ;

< 	int64 j_g(j_g) ;

< 		j_g:long_name = "y-dimension of the v grid" ;

< 		j_g:swap_dim = "YG" ;

< 		j_g:c_grid_axis_shift = -0.5 ;

< 		j_g:axis = "Y" ;

< 	int64 i_g(i_g) ;

< 		i_g:long_name = "x-dimension of the u grid" ;

< 		i_g:swap_dim = "XG" ;

< 		i_g:c_grid_axis_shift = -0.5 ;

< 		i_g:axis = "X" ;

< 	int64 k(k) ;

< 		k:long_name = "z-dimension of the t grid" ;

< 		k:swap_dim = "Z" ;

< 		k:axis = "Z" ;

< 	int64 j(j) ;

< 		j:long_name = "y-dimension of the t grid" ;

< 		j:swap_dim = "YC" ;

< 		j:axis = "Y" ;

< 	int64 k_u(k_u) ;

< 		k_u:long_name = "z-dimension of the w grid" ;

< 		k_u:swap_dim = "Zu" ;

< 		k_u:c_grid_axis_shift = 0.5 ;

< 		k_u:axis = "Z" ;

< 	int64 i(i) ;

< 		i:long_name = "x-dimension of the t grid" ;

< 		i:swap_dim = "XC" ;

< 		i:axis = "X" ;

< 	int64 k_l(k_l) ;

< 		k_l:long_name = "z-dimension of the w grid" ;

< 		k_l:swap_dim = "Zl" ;

< 		k_l:c_grid_axis_shift = -0.5 ;

< 		k_l:axis = "Z" ;

< 	int64 tile ;

< 		tile:long_name = "index of llc grid tile" ;

< 	float XC(j, i) ;

< 		XC:coordinate = "YC XC" ;

< 		XC:units = "degrees_east" ;

---

	double i1(i1) ;

		i1:long_name = "array index 1" ;

		i1:units = "1" ;

	double i2(i2) ;

		i2:long_name = "array index 2" ;

		i2:units = "1" ;

	double i3(i3) ;

		i3:long_name = "array index 3" ;

		i3:units = "1" ;

	double hFacC(i1, i2, i3) ;

		hFacC:long_name = "fractional thickness" ;

		hFacC:units = "1" ;

	double hFacW(i1, i2, i3) ;

		hFacW:long_name = "fractional thickness" ;

		hFacW:units = "1" ;

	double hFacS(i1, i2, i3) ;

		hFacS:long_name = "fractional thickness" ;

		hFacS:units = "1" ;

	double XC(i2, i3) ;

55,57c28,29

< 	float YC(j, i) ;

< 		YC:coordinate = "YC XC" ;

< 		YC:units = "degrees_north" ;

---

		XC:units = "degrees_east" ;

	double YC(i2, i3) ;

59,61c31,32

< 	float XG(j_g, i_g) ;

< 		XG:coordinate = "YG XG" ;

< 		XG:units = "degrees_east" ;

---

		YC:units = "degrees_north" ;

	double XG(i2, i3) ;

63,64c34,35

< 	float YG(j_g, i_g) ;

< 		YG:units = "degrees_north" ;

---

		XG:units = "degrees_east" ;

	double YG(i2, i3) ;

66,104c37,57

< 		YG:coordinates = "YG XG" ;

< 	float CS(j, i) ;

< 		CS:coordinate = "YC XC" ;

< 		CS:units = " " ;

< 		CS:long_name = "AngleCS" ;

< 	float SN(j, i) ;

< 		SN:coordinate = "YC XC" ;

< 		SN:units = " " ;

< 		SN:long_name = "AngleSN" ;

< 	float Zl(k_l) ;

< 		Zl:units = "m" ;

< 		Zl:positive = "down" ;

< 		Zl:long_name = "vertical coordinate of upper cell interface" ;

< 	float Zu(k_u) ;

< 		Zu:units = "m" ;

< 		Zu:positive = "down" ;

< 		Zu:long_name = "vertical coordinate of lower cell interface" ;

< 	float Z(k) ;

< 		Z:units = "m" ;

< 		Z:positive = "down" ;

< 		Z:long_name = "vertical coordinate of cell center" ;

< 	float Zp1(k_p1) ;

< 		Zp1:units = "m" ;

< 		Zp1:positive = "down" ;

< 		Zp1:long_name = "vertical coordinate of cell interface" ;

< 	float dxC(j, i_g) ;

< 		dxC:coordinate = "YC XG" ;

< 		dxC:units = "m" ;

< 		dxC:long_name = "cell x size" ;

< 	float rAs(j_g, i) ;

< 		rAs:units = "m2" ;

< 		rAs:long_name = "cell area" ;

< 		rAs:coordinates = "YG XC" ;

< 	float rAw(j, i_g) ;

< 		rAw:coordinate = "YG XC" ;

< 		rAw:units = "m2" ;

< 		rAw:long_name = "cell area" ;

< 	float Depth(j, i) ;

< 		Depth:coordinate = "XC YC" ;

---

		YG:units = "degrees_north" ;

	double RAC(i2, i3) ;

		RAC:long_name = "grid cell area" ;

		RAC:units = "m^2" ;

	double RAZ(i2, i3) ;

		RAZ:long_name = "grid cell area" ;

		RAZ:units = "m^2" ;

	double DXC(i2, i3) ;

		DXC:long_name = "grid spacing" ;

		DXC:units = "m" ;

	double DYC(i2, i3) ;

		DYC:long_name = "grid spacing" ;

		DYC:units = "m" ;

	double DXG(i2, i3) ;

		DXG:long_name = "grid spacing" ;

		DXG:units = "m" ;

	double DYG(i2, i3) ;

		DYG:long_name = "grid spacing" ;

		DYG:units = "m" ;

	double Depth(i2, i3) ;

		Depth:long_name = "sea floor depth" ;

106,153c59,76

< 		Depth:long_name = "ocean depth" ;

< 	float rA(j, i) ;

< 		rA:coordinate = "YC XC" ;

< 		rA:units = "m2" ;

< 		rA:long_name = "cell area" ;

< 	float dxG(j_g, i) ;

< 		dxG:coordinate = "YG XC" ;

< 		dxG:units = "m" ;

< 		dxG:long_name = "cell x size" ;

< 	float dyG(j, i_g) ;

< 		dyG:coordinate = "YC XG" ;

< 		dyG:units = "m" ;

< 		dyG:long_name = "cell y size" ;

< 	float rAz(j_g, i_g) ;

< 		rAz:coordinate = "YG XG" ;

< 		rAz:units = "m" ;

< 		rAz:long_name = "cell area" ;

< 	float dyC(j_g, i) ;

< 		dyC:coordinate = "YG XC" ;

< 		dyC:units = "m" ;

< 		dyC:long_name = "cell y size" ;

< 	float PHrefC(k) ;

< 		PHrefC:units = "m2 s-2" ;

< 		PHrefC:long_name = "Reference Hydrostatic Pressure" ;

< 	float drC(k_p1) ;

< 		drC:units = "m" ;

< 		drC:long_name = "cell z size" ;

< 	float PHrefF(k_p1) ;

< 		PHrefF:units = "m2 s-2" ;

< 		PHrefF:long_name = "Reference Hydrostatic Pressure" ;

< 	float drF(k) ;

< 		drF:units = "m" ;

< 		drF:long_name = "cell z size" ;

< 	float hFacS(k, j_g, i) ;

< 		hFacS:long_name = "vertical fraction of open cell" ;

< 	float hFacC(k, j, i) ;

< 		hFacC:long_name = "vertical fraction of open cell" ;

< 	float hFacW(k, j, i_g) ;

< 		hFacW:long_name = "vertical fraction of open cell" ;

< 	byte maskW(k, j, i_g) ;

< 		maskW:long_name = "mask denoting wet point at interface" ;

< 		maskW:dtype = "bool" ;

< 	byte maskC(k, j, i) ;

< 		maskC:long_name = "mask denoting wet point at center" ;

< 		maskC:dtype = "bool" ;

< 	byte maskS(k, j_g, i) ;

< 		maskS:long_name = "mask denoting wet point at interface" ;

< 		maskS:dtype = "bool" ;

---

	double AngleCS(i2, i3) ;

		AngleCS:long_name = "grid orientation (cosine)" ;

		AngleCS:units = "m" ;

	double AngleSN(i2, i3) ;

		AngleSN:long_name = "grid orientation (sine)" ;

		AngleSN:units = "m" ;

	double RC(i1) ;

		RC:long_name = "vertical coordinate" ;

		RC:units = "m" ;

	double RF(i1) ;

		RF:long_name = "vertical coordinate" ;

		RF:units = "m" ;

	double DRC(i1) ;

		DRC:long_name = "grid spacing" ;

		DRC:units = "m" ;

	double DRF(i1) ;

		DRF:long_name = "grid spacing" ;

		DRF:units = "m" ;

156,158c79,107

< 		:date_created = "Mon Dec 30 11:13:26 2019" ;

< 		:title = "ECCOv4 MITgcm grid information" ;

< 		:coordinates = "hFacS rAs hFacW Zp1 XC YC XG YG hFacC dxG Depth rA CS drC Z drF Zl dxC maskW maskS PHrefC rAw SN tile Zu PHrefF dyG rAz maskC dyC" ;

---

		:description = "C-grid parameters (see MITgcm documentation for details). -- ECCO v4 ocean state estimate, release 3 -- 1992-2015" ;

		:A = ":Format      = native grid (nctiles w. 13 tiles)" ;

		:B = ":source      = ECCO consortium (http://ecco-group.org/)" ;

		:C = ":institution = JPL/UT/MIT/AER" ;

		:D = ":history     = files revision history :" ;

		:E = "                   04/20/2017: fill in geometry info for blank tiles. \\n" ;

		:F = "                   11/06/2016: third release of ECCO v4 (Ou Wang) \\n" ;

		:G = "               estimates revision history (from second release) : \\n" ;

		:H = "                   employs bi-harmonic viscosity (enhanced near lands), revised \\n" ;

		:I = "                   sea-ice parameters, updated or novel observations (including \\n" ;

		:J = "                   GRACE OBP, Aquarius SSS, global mean scalar SSH & OBP \\n" ;

		:K = "                   time-series, extended and/or expanded in situ TS profiles), \\n" ;

		:L = "                   revised weights including data and control with factors \\n" ;

		:M = "                   to account for grid-size variation and sampling frequency, \\n" ;

		:N = "                   separate time-mean and time-variable data constraint \\n" ;

		:O = "                   and controls, sea-ice costs, and initial U, V, and eta as \\n" ;

		:P = "                   additional controls.\\n " ;

		:Q = ":references  = Fukumori, I., O. Wang, I. Fenty, G. Forget, P. Heimbach, and R. M. Ponte, 2017: \\n" ;

		:R = "                ECCO Version 4 Release 3, http://hdl.handle.net/1721.1/110380, doi:1721.1/110380.\\n" ;

		:S = "                Available at ftp://ecco.jpl.nasa.gov/Version4/Release3/doc/v4r3_estimation_synopsis.pdf \\n" ;

		:T = "               Forget, G., J.-M. Campin, P. Heimbach, C. N. Hill, R. M. Ponte, \\n" ;

		:U = "                and C. Wunsch, 2015: ECCO version 4: an integrated framework for \\n" ;

		:V = "                non-linear inverse modeling and global ocean state estimation. \\n" ;

		:W = "                Geoscientific Model Development, 8, 3071-3104, doi:10.5194/gmd-8-3071-2015 \\n" ;

		:date = "21-Apr-2017" ;

		:Conventions = "CF-1.6" ;

		:_FillValue = NaN ;

		:missing_value = NaN ;

		:program = "file created using gcmfaces_IO/write2nctiles.m \\n" ;

Originally posted by @rabernat in #40

This issue has been raised by @rabernat before. I'd like to know if there's an updated version of the load_grid.m now.
Thank you!