ncview介绍

Ncview: a netCDF visual browser

来源：

/~pierce/ncview_home_

David W. Pierce

Scripps Institution of Oceanography

New version (2.1.2) Released 19 November, 2012

Download

What is it?

Ncview is a visual browser for

netCDF

format files. Typically you would

use ncview to get a quick and easy, push-button look at your netCDF files.

You can view simple movies of the data, view along various dimensions,

take a look at the actual data values, change color maps, invert the data, etc.

It runs on UNIX platforms under X11, R4 or higher. For more information,

check out the

README

file; you can also see a representative

screen

image

(GIF, 66K) of ncview in action.

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Here are some

old versions

in case you need them.

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Trying to get ncview to run on windows under cygwin? I build and use

ncview under cygwin all the time with no problems, so it's definiately

possible. If you are having troubles with cygwin,

this

information

might be of use.

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Trying

to

get

ncview

to

run

on

a

64-bit

Linux

machine,

and

getting

link

errors about

./configure --x-libraries=/usr/X11R6/lib64

(or otherwise specifying the location of the 64-bit X libraries on your

machine).

Note: are you a Ubuntu user, and get configuration errors complaining about

the lack of X development libraries and headers? Read some

comments

from ncview users

on how to get ncview working on Ubuntu.

This version adds support for automatically displaying the last timestep in a

growing netcdf file -- just go to the last frame in the file and hit pause, and

ncview will periodically check if the file has grown. Also, there is a new

'-autoscale' flag that will scale the colormap to each frame automatically.

Download the source

for version 2.1.2 (updated November 19, 2012).

Do you need a

version for Windows

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To install ncview version 2.0, you must:

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Install

HDF-5

, version 1.8.4 or later.

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Install the

netcdf C library

, version 4.1-beta2 or later, and

you

must

compile it with the --enable-netcdf-4 flag set.

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If you want to use udunits, you must install

udunits version 2

. The

udunits library version 1 (which is deprecated) is not supported any

more.

Please notify me of all bugs you find.

Alternatively, you can

download the source

for old, deprecated, but stable

version 1.93g, which does not require the HDF library (but cannot read

netcdf files created in the new, version 4 format as a consequence).

Missing Values, Attributes, and NetCDF Conventions

Ncview follows some of the suggested standards as described in

the

NetCDF User's Guide

, especially the

Attributes Conventions

section. In

particular, the following attributes are taken into account:

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missing_value

: This attribute, which must be of the same type as the

variable it is associated with, is an important one to set if you have

missing values that are indicated by some

-999.9, 1.0e35, or whatever.

If you don't set this attribute, ncview will

not work properly.

units

: A character-type attribute that gives the units of the variable it

is associated with. For example,

long_name

: A character-type attribute that gives the extended, or

more descriptive, name of the variable it is associated with. For

instance, if the variable's name is

title

: This

global

character-type attribute gives some short,

descriptive summary of the meaning or parameters of the data file.

For instance, it might be

Nino Simulation, no mixed layer, D. Pierce SIO/CRD

add_offset, scale_factor

: Ncview respects these attributes,

transparently scaling and offsetting the data as specified. See

the

netCDF documentation on these attributes

for details. In essence,

these attributes let you implement a form of data packing.

Dimensional variables

A convention that ncview follows is that the

values

along a dimension are

stored in variables

of the exact same name

as the dimension itself. I call

these

imagine you have a dimension named

want ncview to understand that the first time is 1995.0, the second is 1996.0,

and the third is 1997.0, then you need to make a

variable

named

has exactly one dimension, the

1996.0, 1997.0).

UDUNITS support

If you format the time axis using the

udunits package

(as I do), then ncview

will properly format the date into something meaningful. For example, a

common units string when using the udunits package is something like

ncview will not just show the (uninformative) value

it as

package BEFORE configuring ncview in the installation process.

Known Bugs

Updated April 6, 2001

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You can get strange behavior if you change the X axis (on a popup

XY plot) for a XY plot *other* than the most recent one. As a

workaround, simply avoid doing this -- if you want to change the X

axis, do it right after popping up the plot.

Revision History

24 February, 2009: 1.93g

: Added some primitive support for mapped

dimensions (i.e., based on the

an overlay correctly with mapped dimensions, and if you hover the cursor

you will get the correct (mapped) location.

Put in a new feature where if you go to the last frame and sit on it, ncview

will periodically check to see if the file has grown since it was last scanned.

If it has grown, then the new last frame is automatically displayed. There is

a new flag,

FRAME, which can be useful in this mode.

Several security suggestions from Mike Duncan have been incorporated into

the code.

8 August, 2008: 1.93d

: Changed license from Gnu GPL v1 to Gnu GPL v3.

Also added better support for cases where multiple input files are processed,

and each has a different time units, AND each has a different calender

(whew!). As part of this, added new routine