1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
|
<!DOCTYPE html>
<!--[if IE 8]><html class="no-js lt-ie9" lang="en" > <![endif]-->
<!--[if gt IE 8]><!--> <html class="no-js" lang="en" > <!--<![endif]-->
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title>IDL interface — HARP 1.5 documentation</title>
<link rel="stylesheet" href="_static/css/theme.css" type="text/css" />
<link rel="stylesheet" href="_static/pygments.css" type="text/css" />
<link rel="stylesheet" href="_static/custom.css" type="text/css" />
<link rel="index" title="Index" href="genindex.html" />
<link rel="next" title="MATLAB interface" href="matlab.html" />
<link rel="prev" title="Variable" href="libharp_variable.html" />
<script src="_static/js/modernizr.min.js"></script>
</head>
<body class="wy-body-for-nav">
<div class="wy-grid-for-nav">
<nav data-toggle="wy-nav-shift" class="wy-nav-side">
<div class="wy-side-scroll">
<div class="wy-side-nav-search">
<a href="index.html" class="icon icon-home"> HARP
</a>
<div class="version">
1.5
</div>
</div>
<div class="wy-menu wy-menu-vertical" data-spy="affix" role="navigation" aria-label="main navigation">
<ul class="current">
<li class="toctree-l1"><a class="reference internal" href="install.html">Installation</a></li>
<li class="toctree-l1"><a class="reference internal" href="conventions/index.html">Conventions</a></li>
<li class="toctree-l1"><a class="reference internal" href="algorithms/index.html">Algorithms</a></li>
<li class="toctree-l1"><a class="reference internal" href="operations.html">Operations</a></li>
<li class="toctree-l1"><a class="reference internal" href="ingestions/index.html">Ingestion definitions</a></li>
<li class="toctree-l1"><a class="reference internal" href="libharp.html">C library</a></li>
<li class="toctree-l1 current"><a class="current reference internal" href="#">IDL interface</a><ul>
<li class="toctree-l2"><a class="reference internal" href="#dimension-types">Dimension types</a></li>
<li class="toctree-l2"><a class="reference internal" href="#data-types">Data types</a></li>
<li class="toctree-l2"><a class="reference internal" href="#unicode">Unicode</a></li>
<li class="toctree-l2"><a class="reference internal" href="#examples">Examples</a></li>
<li class="toctree-l2"><a class="reference internal" href="#api-reference">API reference</a></li>
</ul>
</li>
<li class="toctree-l1"><a class="reference internal" href="matlab.html">MATLAB interface</a></li>
<li class="toctree-l1"><a class="reference internal" href="python.html">Python interface</a></li>
<li class="toctree-l1"><a class="reference internal" href="tools.html">Command line tools</a></li>
</ul>
</div>
</div>
</nav>
<section data-toggle="wy-nav-shift" class="wy-nav-content-wrap">
<nav class="wy-nav-top" aria-label="top navigation">
<i data-toggle="wy-nav-top" class="fa fa-bars"></i>
<a href="index.html">HARP</a>
</nav>
<div class="wy-nav-content">
<div class="rst-content">
<div role="navigation" aria-label="breadcrumbs navigation">
<ul class="wy-breadcrumbs">
<li><a href="index.html">Docs</a> »</li>
<li>IDL interface</li>
<li class="wy-breadcrumbs-aside">
</li>
</ul>
<hr/>
</div>
<div role="main" class="document" itemscope="itemscope" itemtype="http://schema.org/Article">
<div itemprop="articleBody">
<div class="section" id="idl-interface">
<h1>IDL interface</h1>
<p>The Interactive Data Language (IDL) interface consists of a Dynamic Loadable
Module (DLM) that provides the <cite>harp_import</cite>, <cite>harp_export</cite>, <cite>harp_version</cite>,
and ‘harp_unload’ functions.</p>
<p>Products are represented in IDL as structures which can be manipulated freely
from within IDL. A product structure contains a field for each variable
contained in the product and contains the global attributes <cite>source_product</cite>
and <cite>history</cite> (if available). Each variable itself is again a structure containing
the variable attributes (<cite>unit</cite>, <cite>description</cite>, etc.) and a field <cite>data</cite> that
contains the data of the variable. The structure of a variable also contains a
field <cite>name</cite> that contains the case-sensitive name of the variable and (if the
variable is not a scalar) a field <cite>dimension</cite> that contains a list of dimension
names for each dimension of the variable.</p>
<p>Products can be exported as HARP compliant products in any of the file formats
supported by the HARP C library (netCDF/HDF4/HDF5). Such exported products can
subsequently be processed further using the <a class="reference internal" href="tools.html"><span class="doc">HARP command line tools</span></a>.</p>
<div class="section" id="dimension-types">
<h2>Dimension types</h2>
<p>Each non-scalar variable will have a <cite>dimension</cite> field in its structure, which
is a list of strings representing the dimension types (e.g. <cite>time</cite>, <cite>vertical</cite>,
<cite>latitude</cite>, etc.).</p>
</div>
<div class="section" id="data-types">
<h2>Data types</h2>
<p>The HARP IDL interface takes care of the conversion of product and variables
from the C domain to the IDL domain and back. This section describes the
relation between types in the C domain and types in the IDL domain.</p>
<p>The table below shows the type map that is used when importing or ingesting a
product, i.e. when translating from the C domain to the IDL domain.</p>
<p>Variable data arrays are converted to arrays in the product structure. The data
type used for the converted array is determined from the HARP data type of the
variable according to the type map shown below. Zero-dimensional arrays of
length 1 are converted to IDL scalars. The resulting IDL type is also shown in
the type map.</p>
<table border="1" class="docutils">
<colgroup>
<col width="64%" />
<col width="36%" />
</colgroup>
<thead valign="bottom">
<tr class="row-odd"><th class="head">HARP data type</th>
<th class="head">IDL type</th>
</tr>
</thead>
<tbody valign="top">
<tr class="row-even"><td>harp_type_int8</td>
<td>byte</td>
</tr>
<tr class="row-odd"><td>harp_type_int16</td>
<td>int</td>
</tr>
<tr class="row-even"><td>harp_type_int32</td>
<td>long</td>
</tr>
<tr class="row-odd"><td>harp_type_float</td>
<td>float</td>
</tr>
<tr class="row-even"><td>harp_type_double</td>
<td>double</td>
</tr>
<tr class="row-odd"><td>harp_type_string</td>
<td>string</td>
</tr>
</tbody>
</table>
<p>Note that the IDL <cite>byte</cite> type is an unsigned type (since IDL does not have any
8-bit signed type).
The HARP IDL interface will just hard cast signed int8 values to unsigned uint8
values (e.g. -1 will become 255). Make sure that in your operations within IDL
on these 8-bit integers you als treat them as mapped signed integers.
Note also that this holds for the <cite>valid_min</cite> and <cite>valid_max</cite> attributes
(e.g. <cite>valid_min</cite> may end up being higher than <cite>valid_max</cite> in IDL).</p>
</div>
<div class="section" id="unicode">
<h2>Unicode</h2>
<p>Zero-terminated C strings received from the HARP C library are always converted
to instances of type <code class="docutils literal notranslate"><span class="pre">string</span></code> in IDL which are unicode strings.</p>
</div>
<div class="section" id="examples">
<h2>Examples</h2>
<div class="highlight-IDL notranslate"><div class="highlight"><pre><span></span><span class="c c-Singleline">; Import a file as a HARP product.</span>
prod <span class="o">=</span> harp_import(<span class="s2">"filename.ext"</span>)
<span class="c c-Singleline">; Print information about the product.</span>
<span class="nb">help</span>, prod, <span class="o">/</span>struct
<span class="c c-Singleline">; Print information about the variable 'temperature'.</span>
<span class="nb">help</span>, prod.temperature, <span class="o">/</span>struct
<span class="c c-Singleline">; Print the contents of the variable 'temperature'.</span>
<span class="nb">print</span>, prod.temperature.data
<span class="c c-Singleline">; Export the updated product as an HDF4 file (the format must be</span>
<span class="c c-Singleline">; HDF4, HDF5 or netCDF, if no format is specified netCDF is used).</span>
result <span class="o">=</span> harp_export(prod, <span class="s2">"filename.hdf"</span>, <span class="s2">"hdf4"</span>)
<span class="c c-Singleline">; Print the result of the export.</span>
<span class="nb">print</span>, result
<span class="c c-Singleline">; Import the HDF4 file and perform an operation to exclude the variable</span>
<span class="c c-Singleline">; temperature (variable name must be in uppercase).</span>
prod2 <span class="o">=</span> harp_import(<span class="s2">"filename.hdf"</span>, <span class="s2">"exclude(temperature)"</span>);
<span class="c c-Singleline">; Print information about the product.</span>
<span class="nb">help</span>, prod2, <span class="o">/</span>struct
</pre></div>
</div>
</div>
<div class="section" id="api-reference">
<h2>API reference</h2>
<p>This section describes the functions defined by the HARP IDL interface.</p>
<dl class="function">
<dt id="harp_import">
<code class="descname">harp_import</code><span class="sig-paren">(</span><em>filename</em>, <em>operations=""</em>, <em>options=""</em><span class="sig-paren">)</span></dt>
<dd><p>Import a product from a file.</p>
<p>This will first try to import the file as an HDF4, HDF5, or netCDF file that
complies to the HARP Data Format. If the file is not stored using the HARP
format then it will try to import it using one of the available ingestion
modules.</p>
<p>If the filename argument is a list of filenames or a globbing (glob.glob())
pattern then the harp.import_product() function will be called on each
individual file and the result of harp.concatenate() on the imported products
will be returned.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>filename</strong> (<em>str</em>) – Filename of the product to ingest</li>
<li><strong>operations</strong> (<em>str</em>) – Actions to apply as part of the import; should be
specified as a semi-colon separated string of operations.</li>
<li><strong>options</strong> (<em>str</em>) – Ingestion module specific options; should be specified as
a semi-colon separated string of key=value pairs; only
used if the file is not in HARP format.</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first last">Ingested product or error structure.</p>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="function">
<dt id="harp_export">
<code class="descname">harp_export</code><span class="sig-paren">(</span><em>product</em>, <em>filename</em>, <em>file_format="netcdf"</em><span class="sig-paren">)</span></dt>
<dd><p>Export a HARP compliant product.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Parameters:</th><td class="field-body"><ul class="first simple">
<li><strong>product</strong> (<em>str</em>) – Product to export.</li>
<li><strong>filename</strong> (<em>str</em>) – Filename of the exported product.</li>
<li><strong>file_format</strong> (<em>str</em>) – File format to use; one of ‘netcdf’, ‘hdf4’, or
‘hdf5’. If no format is specified, netcdf is used.</li>
</ul>
</td>
</tr>
<tr class="field-even field"><th class="field-name">Returns:</th><td class="field-body"><p class="first last">Error structure with result code.</p>
</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="function">
<dt id="harp_version">
<code class="descname">harp_version</code><span class="sig-paren">(</span><span class="sig-paren">)</span></dt>
<dd><p>The harp_version function returns a string containing the current version
number of HARP. The version number is always of the format ‘x.y.z’, i.e.,
major, minor, and revision numbers, separated by dots.</p>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field-odd field"><th class="field-name">Returns:</th><td class="field-body">HARP version number.</td>
</tr>
</tbody>
</table>
</dd></dl>
<dl class="function">
<dt id="harp_unload">
<code class="descname">harp_unload</code><span class="sig-paren">(</span><span class="sig-paren">)</span></dt>
<dd><p>The harp_unload procedure will clean up any HARP resources. At the first
call to a HARP IDL function the HARP C Library will be initialized which
will require some memory.
A call to harp_unload can then be used to clean up these HARP resources.
After a clean up, the first call to a HARP IDL function will initialize
the HARP C Library again.</p>
<p>This function may be (slightly) useful on systems with little memory.</p>
</dd></dl>
</div>
</div>
</div>
</div>
<footer>
<div class="rst-footer-buttons" role="navigation" aria-label="footer navigation">
<a href="matlab.html" class="btn btn-neutral float-right" title="MATLAB interface" accesskey="n" rel="next">Next <span class="fa fa-arrow-circle-right"></span></a>
<a href="libharp_variable.html" class="btn btn-neutral" title="Variable" accesskey="p" rel="prev"><span class="fa fa-arrow-circle-left"></span> Previous</a>
</div>
<hr/>
<div role="contentinfo">
<p>
© Copyright 2015-2018 S&T, The Netherlands
</p>
</div>
</footer>
</div>
</div>
</section>
</div>
<script type="text/javascript" id="documentation_options" data-url_root="./" src="_static/documentation_options.js"></script>
<script type="text/javascript" src="_static/jquery.js"></script>
<script type="text/javascript" src="_static/underscore.js"></script>
<script type="text/javascript" src="_static/doctools.js"></script>
<script async="async" type="text/javascript" src="/usr/share/javascript/mathjax/MathJax.js?config=TeX-AMS-MML_HTMLorMML"></script>
<script type="text/javascript" src="_static/js/theme.js"></script>
<script type="text/javascript">
jQuery(function () {
SphinxRtdTheme.Navigation.enable(true);
});
</script>
</body>
</html>
|
