[ncl-talk] plotting country outline with shapefiles
Dave Allured - NOAA Affiliate
dave.allured at noaa.gov
Tue Jan 5 16:16:04 MST 2021
SB,
Thank you for running some diagnostics. The direct approach with addfiles
is important. The following things are now eliminated from this problem:
* Your NCL scripts
* Any part of NCL shapefile_utils.ncl
These remain as possible candidates:
* Your actual shapefiles
* Shapefile driver inside NCL
* Shapefile support libraries
I see that there are two different file dates on your shapefile. Please
ensure they are actually the same file. Check this with "md5sum
file_gor_2011.shp" on the Linux command line. They should result in
identical checksum strings.
If you know how NCL was installed on each machine, then you should be able
to check the version numbers of the shapefile support libraries. Look at
GDAL (libgdal) in particular. There may be other libraries involved. I do
not know the details of the library stack for shapefiles. If you find
different library versions, I suggest updating the older one to a more
recent version. It may be necessary to rebuild or re-install NCL to
accomplish this.
If you have "ogrinfo" installed for the Linux command line, use this to
list the shapefile layer names like this:
ogrinfo file_gor_2011.shp
Then insert one of those layer names into this command to get a geometry
summary for that layer. The bounding coordinates are reported on a line
labeled "Extents". See whether the geometry is consistent between machines.
ogrinfo -geom=NO -fields=NO file_gor_2011.shp *layer-name*
This command is a part of GDAL, not NCL. If you have an out of date
library problem, it might show up in the geometry results from ogrinfo. I
can not guarantee this, but it is easy to try if you have ogrinfo installed.
On Tue, Jan 5, 2021 at 1:40 PM S Br <sbr.climate at gmail.com> wrote:
> Hi Rick,
> Thanks for trying.
> I am using the same shapefile_utils.ncl across the two machines.
> As you suggest, I have tried the command in both machines and it looks
> like x/y coordinates are swapped in maschine #2 as shown below.
>
> *machine #1*
> (0) -0.1916935366010736 51.34212550232069
> (1) -0.1918504471635003 51.34216369759741
> (2) -0.1919426195340767 51.3421861363549
> .
> .
> .
> (25817) -0.1912990774713476 51.34202950288345
> (25818) -0.1916318559031973 51.34211049447309
> (25819) -0.1916935366010736 51.34212550232069
>
> *machine #2*
> (0) 51.34212549581116 -0.1916934955276336
> (1) 51.34216369108803 -0.1918504060899556
> (2) 51.34218612984562 -0.1919425784604706
> .
> .
> .
> (25817) 51.34202949637353 -0.1912990363981704
> (25818) 51.34211048796352 -0.1916318148297985
> (25819) 51.34212549581116 -0.1916934955276336
>
>
> On Tue, Jan 5, 2021 at 7:11 PM Rick Brownrigg <brownrig at ucar.edu> wrote:
>
>> Well this is truly bizarre. There's nothing I can think of that would or
>> should account for the lat/lon coordinate swapping between the two machines
>> (unless the shapefile_utils.ncl files are different across the two
>> machines). Things work as expected for me. Unfortunately, without access to
>> something like machine #2 that exhibits the behavior, I personally have no
>> way of drilling down further to find out what the problem is.
>>
>> Not that this helps solve the problem, but I'm curious if the x/y
>> coordinates are really juxtaposed; on machine #2:
>>
>> f=addfile("file_gor_2011.shp","r")
>> print(f->x + " " + f->y)
>>
>> Do those values look like they are swapped?
>>
>> I wish I had a better answer for you :-/
>>
>> Rick
>>
>>
>> On Tue, Jan 5, 2021 at 8:37 AM S Br <sbr.climate at gmail.com> wrote:
>>
>>> Hi Rick,
>>> The below are the details.
>>>
>>> uname -a
>>> Computer#1
>>> Linux sbclim 4.15.0-128-generic #131-Ubuntu SMP Wed Dec 9 06:57:35 UTC
>>> 2020 x86_64 x86_64 x86_64 GNU/Linux
>>> Computer#2
>>> Linux sbclim 3.10.0-1127.19.1.el7.x86_64 #1 SMP Tue Aug 25 17:23:54 UTC
>>> 2020 x86_64 x86_64 x86_64 GNU/Linux
>>>
>>> ls -l file_gor_2011.shp
>>> Computer#1
>>> -rw-r--r-- 1 climdir env 413276 Dec 8 16:11 file_gor_2011.shp
>>> Computer#2
>>> -rw-r--r-- 1 climdir users 413276 Jan 5 10:54 file_gor_2011.shp
>>>
>>> Please find attached here the shape files.
>>>
>>> Thanks
>>> SB
>>>
>>>
>>> On Tue, Jan 5, 2021 at 2:37 PM Rick Brownrigg <brownrig at ucar.edu> wrote:
>>>
>>>> Hi,
>>>>
>>>> That result is very strange indeed. What are computers 1 and 2, i.e.,
>>>> what is the output of:
>>>>
>>>> uname -a
>>>>
>>>> And just to be certain, what is the output of this on each computer:
>>>>
>>>> cd ...to-directory-where-file_gor_2011.shp-resides....
>>>> ls -l file_gor_2011.shp
>>>>
>>>> Finally, can you send me file_gor_2011.shp (recall that means the .sph,
>>>> .shx, .dbf files)?
>>>>
>>>> Rick
>>>>
>>>> On Tue, Jan 5, 2021 at 5:53 AM S Br via ncl-talk <
>>>> ncl-talk at mailman.ucar.edu> wrote:
>>>>
>>>>> Hi Dave,
>>>>> Thanks for your reply.
>>>>> I have now compared the diagnostic results between the two computers
>>>>> and the below are the results.
>>>>> *Computer#1:*
>>>>> (0)
>>>>> ======================================================================
>>>>> (0) Filename: "file_gor_2011.shp"
>>>>> (0) Geometry type: polygon
>>>>> (0) # of features: 1
>>>>> (0) Min/max lat: 51.29/ 51.69
>>>>> (0) Min/max lon: -0.51/ 0.33
>>>>> (0) Variable names and their types:
>>>>> (0) geometry : integer
>>>>> (0) segments : integer
>>>>> (0) x : double
>>>>> (0) y : double
>>>>> (0) label : string
>>>>> (0) name : string
>>>>> (0) code : string
>>>>> (0)
>>>>> ======================================================================
>>>>> *Computer#2:*
>>>>> (0)
>>>>> ======================================================================
>>>>> (0) Filename: "file_gor_2011.shp"
>>>>> (0) Geometry type: polygon
>>>>> (0) # of features: 1
>>>>> (0) Min/max lat: -0.51/ 0.33
>>>>> (0) Min/max lon: 51.29/ 51.69
>>>>> (0) Variable names and their types:
>>>>> (0) geometry : integer
>>>>> (0) segments : integer
>>>>> (0) x : double
>>>>> (0) y : double
>>>>> (0) label : string
>>>>> (0) name : string
>>>>> (0) code : string
>>>>> (0)
>>>>> ======================================================================
>>>>>
>>>>> I could see in one computer (computer#2 above) that the latitude
>>>>> values are replacing the longitude values and vice versa, and that may be
>>>>> the reason the country outlines are not displaying here.
>>>>>
>>>>> Could you please suggest how to solve this issue? I am using the same
>>>>> data, scripts and only difference is the computer.
>>>>>
>>>>> Thank you.
>>>>> SB
>>>>>
>>>>>
>>>>> On Wed, Dec 9, 2020 at 5:30 PM Dave Allured - NOAA Affiliate <
>>>>> dave.allured at noaa.gov> wrote:
>>>>>
>>>>>> It would be better to apply debugging techniques to narrow down the
>>>>>> problem, rather than to speculate as to the cause. Use *addfile* to
>>>>>> see if NCL can read the shapefile. Use diagnostic print statements to
>>>>>> examine the shapefile structure in memory. Use *gsn_add_polygon* to
>>>>>> see if NCL can draw a simple outline.
>>>>>>
>>>>>> To understand the structure, refer to the shapefile documentation at
>>>>>> the top of the NCL shapefiles example page. That mentions a special
>>>>>> procedure *print_shapefile_info* which will print additional useful
>>>>>> details. Compare diagnostic results between your two computers. Good luck.
>>>>>>
>>>>>>
>>>>>> On Wed, Dec 9, 2020 at 1:16 AM S Br via ncl-talk <
>>>>>> ncl-talk at mailman.ucar.edu> wrote:
>>>>>>
>>>>>>> Hi All,
>>>>>>> I am trying to plot a figure using the shapefile. Everything is
>>>>>>> working fine with the NCL script but it doesn't draw the country outline
>>>>>>> given as a shapefiles. However, the same script works fine in another
>>>>>>> computer and draws the required country outline using the shapefile.
>>>>>>> What could be the possible reason that the NCL script works fine but
>>>>>>> fails to draw the country outline using shapefiles without showing any
>>>>>>> error?
>>>>>>>
>>>>>>> Both the computers are installed with the NCL 6.6.2.
>>>>>>>
>>>>>>> Thank you.
>>>>>>> SB
>>>>>>>
>>>>>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mailman.ucar.edu/pipermail/ncl-talk/attachments/20210105/629de20c/attachment-0001.html>
More information about the ncl-talk
mailing list