[ncl-talk] Visualization of SAF NWC products
Athanasios Karagiannidis
thankar at live.com
Mon Feb 15 02:46:12 MST 2016
Dear Rick,
I understand that you did not manage to identify the problem.
If that is the problem , are there any suggestions regarding the visualization of SAF NWC (basically meteosat) products?
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
Date: Mon, 8 Feb 2016 20:38:47 -0700
Subject: Re: [ncl-talk] Visualization of SAF NWC products
From: brownrig at ucar.edu
To: thankar at live.com
Hi Sakis,
Offhand I don't know what is going on here. It almost appears that the proverbial "rug has been yanked out from under us", with respect to the projection software -- I've used that package for over a dozen years, and "+proj=latlon" is/was by all accounts a legitimate projection spec. I get the same result as you on my system, which has the latest proj4 release -- I want to try and track down a system with an older release in the morning and see if I get the same results.
Rick
On Mon, Feb 8, 2016 at 9:10 AM, Athanasios Karagiannidis <thankar at live.com> wrote:
Dear Rick
I'm coming back with a problem regarding an earlier problem i had some time ago.
I was trying to visualize Meteosat projection data (for example the CTTH_HEIGHT parameter in the h5 file) and you provided the script i attach which is supposed to draw the png i also attach.
However when i try to execute, i get the following message:
(0) Span in X direction (meters): 2.16929e+06
(0) Span in Y direction (meters): 1.53321e+06
(0) calculated maxX: 3.03041e+06 vs. reported in file: 3.03041e+06
(0) calculated maxY: 4.4706e+06 vs. reported in file: 4.4706e+06
FATAL ERROR: Can not make a projection out of <+proj=lonlat>
fatal:TransformCoordinate: Couldn't transform coordinates.
fatal:["Execute.c":8578]:Execute: Error occurred at or near line 38 in file geos2LL.ncl
(0) longitude range: 861115.75, 3030407.25
(0) latitude range: 2937395, 4470601
(0) gsn_csm_map_ce: Warning: you set mpMaxLonF to a value > 180, but
(0) didn't set mpCenterLonF. Setting mpCenterLonF to 1945761.5
warning:MapTransInitialize: mpMinLonF out of range: resetting
warning:MapTransInitialize: mpMaxLonF out of range: resetting
warning:MapSetTrans: map limits invalid - using maximal area
warning:mpMapLimitMode is not a valid resource in map at this time
(0) get_lat_values: Warning: Your latitude values do not fall between -90 and 90 inclusive.
(0) You will not get 'nice' latitude labels.
warning:Attempt to reference attribute (minor) which is undefined
I think the problem begins at dstProj = "+proj=lonlat".
As a result nothing is plotted.
Could you help me?
I attach a data file in case you need it.
Thank you in advance
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
Date: Fri, 5 Jun 2015 15:16:34 -0600
Subject: Re: [ncl-talk] Visualization of SAF NWC products
From: brownrig at ucar.edu
To: thankar at live.com
CC: haley at ucar.edu
Hi Sakis,
The file does indeed seem to have all the requisite projection information in it to calculate latlon coordinates, using, our interface to the proj4 library. I've attached a script that does just that. I've also attached the the plot it generates. I'm a bit troubled by the shape of the lat/lon grid, and by the fact that the spans in X/Y in meters do not align with what gets reported in Google Earth. However, the native projection is "geostationary view", and its possible that it imparts rather severe distortion of distance at the edges of the projection, so maybe the values are reasonable.
Do you have a feel for what the shape/extent of your data should look like?
Let me know what you think...Rick
On Fri, Jun 5, 2015 at 12:53 AM, Athanasios Karagiannidis <thankar at live.com> wrote:
Dear Mary
Thank you for your help!
The speed
of the code was indeed an issue.
Regarding
the lat / lon issue:
1. Yes, they are not equally spaced.
2. Yes, the whole information about the
way the rasterized data should be assigned to lat/lon is (to my knowledge) included
in the h5 files attributes.
3. I have a way to bypass the problem
by loading 2 separate files that provide lat/lon info. However I would like to
be independent of them, for a series of reasons.
I’m looking
forward to Rick’s response.
Kind
regards
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
Date: Thu, 4 Jun 2015 22:59:55 -0600
Subject: Re: [ncl-talk] Visualization of SAF NWC products
From: haley at ucar.edu
To: thankar at live.com
CC: brownrig at ucar.edu
Dear Sakis,
You've been so patient, thanks! As a start, I recommend that you use raster mode, as it is much faster:
res at cnFillMode = "RasterFill"The code ran in about 1 second, compared to minutes before. The issue here is that you don't have lat/lon arrays on the file, so you have to either construct them yourself, as you are trying to do with the fspan function, or else if you know the exact map projection, then you can just draw the contours in the correct map project, with res at tfDoNDCOverlay = True. This is basically telling NCL that you know what the projection is, and to not require lat/lon coordinates.I think the use of "fspan" to generate the lat/lon values may be too simplistic, as this is assuming your lat/lon values are equally spaced, and not rotated. I have a feeling that neither of these conditions are true for your data. But, I could be wrong! I just know that the plot doesn't look quite right if you run the script as it.I can't tell from your file what the correct map projection is, as I'm not familiar with the terminology it's using. It looks like the information is all there in the file attribute information: GEOTRANSFORM_GDAL_TABLE : -5570248.832537, 3000.403357, 0.000000, 5570248.832537,0.000000, -3000.403357
PROJECTION : +proj=geos +a=6378169.0 +b=6356583.8 +lon_0=0.0 +h=35785831.000, -3000.403357
PROJECTION_NAME : GEOS<+000.0>a=6378169.0 +b=6356583.8 +lon_0=0.0 +h=35785831.000, -3000.403357
REGION_NAME : Greece000.0>a=6378169.0 +b=6356583.8 +lon_0=0.0 +h=35785831.000, -3000.403357
XGEO_LOW_RIGHT : 3030407.390714755
XGEO_UP_LEFT : 861115.7635001335
YGEO_LOW_RIGHT : 2937394.886643311
YGEO_UP_LEFT : 4470601.002143549
My guess is that you might be able to use one of our unadvertised, internal GDAL transformation routines to convert this information into lat/lon coordinates. I've CC'ed Rick Brownrigg who may know something about this.
--Mary
On Sun, May 31, 2015 at 1:48 AM, Athanasios Karagiannidis <thankar at live.com> wrote:
Dear Mary
I attached the latets script that was prepared for me along with a sample dataset (h5 file).
Thank you for your interest and help.
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
Date: Sat, 30 May 2015 15:34:05 -0600
Subject: Re: [ncl-talk] Visualization of SAF NWC products
From: haley at ucar.edu
To: thankar at live.com
CC: ncl-talk at ucar.edu
Dear Sakis,
Can you provide the data and the latest script that you are using, so we can take a look? You can use our ftp if you don't have a place to put it:
http://www.ncl.ucar.edu/report_bug.shtml#HowToFTP
--Mary
On Thu, May 28, 2015 at 2:05 AM, Athanasios Karagiannidis <thankar at live.com> wrote:
Good
morning to all!
Following the
earlier conversation (to which I respond) I think I have the obligation to
clarify some issues, since these conversations are available to all users, and
they are used to solve various kinds of problems.
After doing
some more tests, I found out that the otherwise elegant and technically
flawless script that was kindly prepared for me, does not illustrates correctly
the CTTH_HEIGHT field. The problem is related to the fact that the line/column
space of the raster data does not refer to a regular lat/lon space. In simple
words the pixels of the raster data are not equal in lat/lon dimensions.
Regarding
more technical issues:
XGEO_LOW_RIGHT,
XGEO_UP_LEFT, YGEO_LOW_RIGHT, YGEO_UP_LEFT are not given in degrees but in meters.
dims =
dimsizes(CT) , lat = fspan(minLat, maxLat, dims(0)) and lon = fspan(minLon,
maxLon, dims(1)) are producing a regular
grid (which is not correct)
It would be
really helpful if a script could project correctly Meteosat fields (I think safnwc
is using the Meteosat grid) but I’m not sure that such a thing exists.
Kind
regards
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
From: thankar at live.com
To: haley at ucar.edu
Date: Sat, 21 Feb 2015 08:29:02 +0000
CC: ncl-talk at ucar.edu
Subject: Re: [ncl-talk] Visualization of SAF NWC products
Mary, thank you for your input!
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
Date: Fri, 20 Feb 2015 09:46:02 -0700
Subject: Re: [ncl-talk] Visualization of SAF NWC products
From: haley at ucar.edu
To: thankar at live.com
CC: huangwei at ucar.edu; ncl-talk at ucar.edu
The issue with "namedcolor2rgb" is not really an issue. The code should still work. The error message is just misleading, but can be ignored.
We have fixed the incorrect error message for the V6.3.0 release coming next month.
--Mary
On Fri, Feb 20, 2015 at 1:46 AM, Athanasios Karagiannidis <thankar at live.com> wrote:
Wei,
Your help is more than appreciated.
I will update my NCL version.
Kind regards
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
From: huangwei at ucar.edu
Date: Thu, 19 Feb 2015 09:23:14 -0700
Subject: Re: [ncl-talk] Visualization of SAF NWC products
To: thankar at live.com
CC: ncl-talk at ucar.edu
Sakis,
Attached is script which looks more like what you see with HDFview,but used a whole user-defined color table.
"gsdtol" is a standard color-table name, in NCL 6.2.1. Your NCL of 6.1.2is a little bit old, and I strongly suggest you update your NCL to the newest version.
Compare the newly attached script and the script before,you'll be able to figure out that the difference is the projection applied.So you can turn on/off those options based on your requirement.
A new png file is attached as well.
Regards,
Wei
================================================1850 Table Mesa Dr.Boulder, CO 80307Phone: 303-497-8924
On Thu, Feb 19, 2015 at 4:07 AM, Athanasios Karagiannidis <thankar at live.com> wrote:
Dear Wei
I'm more than thankful for your script! It is excellent in correctly reading my data and more or less what i wanted regarding the visualization.
I have just 3 comments:
1. I would really like to see the drawn field (in example the CT) even over land. How can i do this?
2. When i run the script in my machine i get the following warnings:
(0) Warning: namedcolor2rgb: 'gsdtol' is not a valid named color.
(0) Will return missing values for this color.
Is 'gsdtol' a custom made color? In this case maybe i should replace it.
3. In the example HDFView visualization i provided the grid was not "tilted" to the left (a projection issue i guess!). How should i make your visualization, so it looks like the HDFView one?
Thank you in advance!
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
From: huangwei at ucar.edu
Date: Wed, 18 Feb 2015 13:26:21 -0700
Subject: Re: [ncl-talk] Visualization of SAF NWC products
To: thankar at live.com
CC: ncl-talk at ucar.edu
Sakis,
You may take a look of the attached script and pdf file to see if these are what you wanted.
Thanks,
Wei
================================================1850 Table Mesa Dr.Boulder, CO 80307Phone: 303-497-8924
On Wed, Feb 18, 2015 at 1:38 AM, Athanasios Karagiannidis <thankar at live.com> wrote:
Dear sirs/madams
I want to visualize SAF NWC output data using ncl. They are included in an h5 file.
These data are not in a simple lat-lon grid.
After an earlier contact with you i managed to visualize them by creating such a grid, but i feel that the image is not accurate.
What i want to help me with, is to tell me weather there is a standard way or an already existing script to visualize correctly that kind of data.
To help you I provide the following:
1. A sample datafile.
2. The printVarSummary output
3. A screenshot of the HDFView visualization of the variable where the Variable info are shown (more or less the same info with printVarSummary).
4. The script i used (although, i do not think that you need that!). The lat/lon limits that i have n my script are not acurate. I used them to make the visualization.
---------- printVarSummary------------------------------
ncl 2> printVarSummary(CT)
Variable: CT
Type: ubyte
Total Size: 370688 bytes
370688 values
Number of Dimensions: 2
Dimensions and sizes: [DIM_000 | 512] x [DIM_001 | 724]
Coordinates:
Number Of Attributes: 11
CLASS : IMAGE_INDEXED
ID : CTTH_HEIGHTED
IMAGE_COLORMODEL : RGBH_HEIGHTED
IMAGE_SUBCLASS : IMAGE_INDEXED
IMAGE_VERSION : 1.0GE_INDEXED
N_COLS : 724
N_LINES : 512
OFFSET : -2000
PALETTE : ��8�3
PRODUCT : CTTHE_INDEXED
SCALING_FACTOR : 200
---------------------------------------------------------------------------------
---------------- My Script ---------------------------------------------------
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
begin
cdf_file = addfile("SAFNWC_MSG2_CTTH_200812121100_Greece______.h5","r")
CT = cdf_file->CTTH_HEIGHT(:,:)
res = True
lat = fspan(50,20,512) ; A.K. -- reverse the matrix
lon = fspan(10,30,724)
CT!0 = "lat" ;-- set name of CT dimension 0
CT!1 = "lon" ;-- set name of CT dimension 1
CT&lat = lat ;-- assign lat array to CT
CT&lon = lon ;-- assign lon array to CT
CT&lat at units = "degrees_north" ;-- set the units of the named coordinate lat
CT&lon at units = "degrees_east" ;-- set the units of the named coordinate lon
res at gsnAddCyclic = False
res at tiMainString = "Default Color" ; main title
res at cnFillOn = True ; turn on color fill
res at mpMaxLatF = 50 ; choose subregion
res at mpMinLatF = 20
res at mpMaxLonF = 30
res at mpMinLonF = 10
xwks = gsn_open_wks("pdf","CloudTops")
plot = gsn_csm_contour_map(xwks,CT,res)
end
--------------------------------------------------------------------------------
Thank you in advance.
Sakis
Athanasios F. Karagiannidis
Physicist, PhD Meteorology and Climatology
E-mail: thankar at live.com
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