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2013-04-02 14:02:10 +00:00
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<h1>get.c</h1>get.c How to get values through the key names.<p>
<div class="fragment"><pre class="fragment"><a name="l00001"></a>00001
<a name="l00010"></a>00010 <span class="comment">/*</span>
<a name="l00011"></a>00011 <span class="comment"> * C Implementation: get</span>
<a name="l00012"></a>00012 <span class="comment"> *</span>
<a name="l00013"></a>00013 <span class="comment"> * Description: how to get values using keys.</span>
<a name="l00014"></a>00014 <span class="comment"> *</span>
<a name="l00015"></a>00015 <span class="comment"> * Author: Enrico Fucile</span>
<a name="l00016"></a>00016 <span class="comment"> *</span>
<a name="l00017"></a>00017 <span class="comment"> *</span>
<a name="l00018"></a>00018 <span class="comment"> */</span>
<a name="l00019"></a>00019 <span class="preprocessor">#include &lt;stdio.h&gt;</span>
<a name="l00020"></a>00020 <span class="preprocessor">#include &lt;stdlib.h&gt;</span>
<a name="l00021"></a>00021
GRIB-902: Update copyright notices: 2015 -> 2016
2015-12-31 12:44:51 +00:00
<a name="l00022"></a>00022 <span class="preprocessor">#include "<a class="code" href="grib__api_8h.html" title="Copyright 2005-2016 ECMWF.">grib_api.h</a>"</span>
Add the html dir
2013-04-02 14:02:10 +00:00
<a name="l00023"></a>00023
<a name="l00024"></a>00024 <span class="keywordtype">int</span> main(<span class="keywordtype">int</span> argc, <span class="keywordtype">char</span>** argv) {
<a name="l00025"></a>00025 <span class="keywordtype">int</span> err = 0;
<a name="l00026"></a>00026 <span class="keywordtype">double</span> *values = NULL;
<a name="l00027"></a>00027 <span class="keywordtype">size_t</span> values_len= 0;
<a name="l00028"></a>00028
<a name="l00029"></a>00029 <span class="keywordtype">size_t</span> i = 0;
<a name="l00030"></a>00030
<a name="l00031"></a>00031 <span class="keywordtype">double</span> latitudeOfFirstGridPointInDegrees;
<a name="l00032"></a>00032 <span class="keywordtype">double</span> longitudeOfFirstGridPointInDegrees;
<a name="l00033"></a>00033 <span class="keywordtype">double</span> latitudeOfLastGridPointInDegrees;
<a name="l00034"></a>00034 <span class="keywordtype">double</span> longitudeOfLastGridPointInDegrees;
<a name="l00035"></a>00035
<a name="l00036"></a>00036 <span class="keywordtype">double</span> jDirectionIncrementInDegrees;
<a name="l00037"></a>00037 <span class="keywordtype">double</span> iDirectionIncrementInDegrees;
<a name="l00038"></a>00038
<a name="l00039"></a>00039 <span class="keywordtype">long</span> numberOfPointsAlongAParallel;
<a name="l00040"></a>00040 <span class="keywordtype">long</span> numberOfPointsAlongAMeridian;
<a name="l00041"></a>00041
<a name="l00042"></a>00042 <span class="keywordtype">double</span> average = 0;
<a name="l00043"></a>00043
<a name="l00044"></a>00044 FILE* in = NULL;
<a name="l00045"></a>00045 <span class="keywordtype">char</span>* filename = <span class="stringliteral">"../../data/regular_latlon_surface.grib1"</span>;
<a name="l00046"></a>00046 <a name="a0"></a><a class="code" href="group__grib__handle.html#g309a5ee24f4c730646d3f80ad0ef5f1b">grib_handle</a> *h = NULL;
<a name="l00047"></a>00047
<a name="l00048"></a>00048 in = fopen(filename,<span class="stringliteral">"r"</span>);
<a name="l00049"></a>00049 <span class="keywordflow">if</span>(!in) {
<a name="l00050"></a>00050 printf(<span class="stringliteral">"ERROR: unable to open file %s\n"</span>,filename);
<a name="l00051"></a>00051 <span class="keywordflow">return</span> 1;
<a name="l00052"></a>00052 }
<a name="l00053"></a>00053
<a name="l00054"></a>00054 <span class="comment">/* create new handle from a message in a file*/</span>
<a name="l00055"></a>00055 h = <a name="a1"></a><a class="code" href="group__grib__handle.html#g5e24f8499aa7e4178ccc25a5de3145c5" title="Create a handle from a file resource.">grib_handle_new_from_file</a>(0,in,&amp;err);
<a name="l00056"></a>00056 <span class="keywordflow">if</span> (h == NULL) {
<a name="l00057"></a>00057 printf(<span class="stringliteral">"Error: unable to create handle from file %s\n"</span>,filename);
<a name="l00058"></a>00058 }
<a name="l00059"></a>00059
<a name="l00060"></a>00060 <span class="comment">/* get as a long*/</span>
<a name="l00061"></a>00061 GRIB_CHECK(<a name="a2"></a><a class="code" href="group__get__set.html#g03cfa6762312face1a3cc3ef23e16526" title="Get a long value from a key, if several keys of the same name are present, the last...">grib_get_long</a>(h,<span class="stringliteral">"numberOfPointsAlongAParallel"</span>,&amp;numberOfPointsAlongAParallel),0);
<a name="l00062"></a>00062 printf(<span class="stringliteral">"numberOfPointsAlongAParallel=%ld\n"</span>,numberOfPointsAlongAParallel);
<a name="l00063"></a>00063
<a name="l00064"></a>00064 <span class="comment">/* get as a long*/</span>
<a name="l00065"></a>00065 GRIB_CHECK(<a class="code" href="group__get__set.html#g03cfa6762312face1a3cc3ef23e16526" title="Get a long value from a key, if several keys of the same name are present, the last...">grib_get_long</a>(h,<span class="stringliteral">"numberOfPointsAlongAMeridian"</span>,&amp;numberOfPointsAlongAMeridian),0);
<a name="l00066"></a>00066 printf(<span class="stringliteral">"numberOfPointsAlongAMeridian=%ld\n"</span>,numberOfPointsAlongAMeridian);
<a name="l00067"></a>00067
<a name="l00068"></a>00068 <span class="comment">/* get as a double*/</span>
<a name="l00069"></a>00069 GRIB_CHECK(<a name="a3"></a><a class="code" href="group__get__set.html#g5d9eeda38bf59ee3fa9ce3f92e65009e" title="Get a double value from a key, if several keys of the same name are present, the...">grib_get_double</a>(h,<span class="stringliteral">"latitudeOfFirstGridPointInDegrees"</span>,&amp;latitudeOfFirstGridPointInDegrees),0);
<a name="l00070"></a>00070 printf(<span class="stringliteral">"latitudeOfFirstGridPointInDegrees=%g\n"</span>,latitudeOfFirstGridPointInDegrees);
<a name="l00071"></a>00071
<a name="l00072"></a>00072 <span class="comment">/* get as a double*/</span>
<a name="l00073"></a>00073 GRIB_CHECK(<a class="code" href="group__get__set.html#g5d9eeda38bf59ee3fa9ce3f92e65009e" title="Get a double value from a key, if several keys of the same name are present, the...">grib_get_double</a>(h,<span class="stringliteral">"longitudeOfFirstGridPointInDegrees"</span>,&amp;longitudeOfFirstGridPointInDegrees),0);
<a name="l00074"></a>00074 printf(<span class="stringliteral">"longitudeOfFirstGridPointInDegrees=%g\n"</span>,longitudeOfFirstGridPointInDegrees);
<a name="l00075"></a>00075
<a name="l00076"></a>00076 <span class="comment">/* get as a double*/</span>
<a name="l00077"></a>00077 GRIB_CHECK(<a class="code" href="group__get__set.html#g5d9eeda38bf59ee3fa9ce3f92e65009e" title="Get a double value from a key, if several keys of the same name are present, the...">grib_get_double</a>(h,<span class="stringliteral">"latitudeOfLastGridPointInDegrees"</span>,&amp;latitudeOfLastGridPointInDegrees),0);
<a name="l00078"></a>00078 printf(<span class="stringliteral">"latitudeOfLastGridPointInDegrees=%g\n"</span>,latitudeOfLastGridPointInDegrees);
<a name="l00079"></a>00079
<a name="l00080"></a>00080 <span class="comment">/* get as a double*/</span>
<a name="l00081"></a>00081 GRIB_CHECK(<a class="code" href="group__get__set.html#g5d9eeda38bf59ee3fa9ce3f92e65009e" title="Get a double value from a key, if several keys of the same name are present, the...">grib_get_double</a>(h,<span class="stringliteral">"longitudeOfLastGridPointInDegrees"</span>,&amp;longitudeOfLastGridPointInDegrees),0);
<a name="l00082"></a>00082 printf(<span class="stringliteral">"longitudeOfLastGridPointInDegrees=%g\n"</span>,longitudeOfLastGridPointInDegrees);
<a name="l00083"></a>00083
<a name="l00084"></a>00084 <span class="comment">/* get as a double*/</span>
<a name="l00085"></a>00085 GRIB_CHECK(<a class="code" href="group__get__set.html#g5d9eeda38bf59ee3fa9ce3f92e65009e" title="Get a double value from a key, if several keys of the same name are present, the...">grib_get_double</a>(h,<span class="stringliteral">"jDirectionIncrementInDegrees"</span>,&amp;jDirectionIncrementInDegrees),0);
<a name="l00086"></a>00086 printf(<span class="stringliteral">"jDirectionIncrementInDegrees=%g\n"</span>,jDirectionIncrementInDegrees);
<a name="l00087"></a>00087
<a name="l00088"></a>00088 <span class="comment">/* get as a double*/</span>
<a name="l00089"></a>00089 GRIB_CHECK(<a class="code" href="group__get__set.html#g5d9eeda38bf59ee3fa9ce3f92e65009e" title="Get a double value from a key, if several keys of the same name are present, the...">grib_get_double</a>(h,<span class="stringliteral">"iDirectionIncrementInDegrees"</span>,&amp;iDirectionIncrementInDegrees),0);
<a name="l00090"></a>00090 printf(<span class="stringliteral">"iDirectionIncrementInDegrees=%g\n"</span>,iDirectionIncrementInDegrees);
<a name="l00091"></a>00091
<a name="l00092"></a>00092 <span class="comment">/* get the size of the values array*/</span>
<a name="l00093"></a>00093 GRIB_CHECK(<a name="a4"></a><a class="code" href="group__get__set.html#g18b622ed86b24d5e5fcab70c309fc245" title="Get the number of coded value from a key, if several keys of the same name are present...">grib_get_size</a>(h,<span class="stringliteral">"values"</span>,&amp;values_len),0);
<a name="l00094"></a>00094
<a name="l00095"></a>00095 values = malloc(values_len*<span class="keyword">sizeof</span>(<span class="keywordtype">double</span>));
<a name="l00096"></a>00096
<a name="l00097"></a>00097 <span class="comment">/* get data values*/</span>
<a name="l00098"></a>00098 GRIB_CHECK(<a name="a5"></a><a class="code" href="group__get__set.html#g61f1029d7f37d51f33835e218d58378a" title="Get double array values from a key.">grib_get_double_array</a>(h,<span class="stringliteral">"values"</span>,values,&amp;values_len),0);
<a name="l00099"></a>00099
<a name="l00100"></a>00100 average = 0;
<a name="l00101"></a>00101 <span class="keywordflow">for</span>(i = 0; i &lt; values_len; i++)
<a name="l00102"></a>00102 average += values[i];
<a name="l00103"></a>00103
<a name="l00104"></a>00104 average /=(double)values_len;
<a name="l00105"></a>00105
<a name="l00106"></a>00106 free(values);
<a name="l00107"></a>00107
<a name="l00108"></a>00108 printf(<span class="stringliteral">"There are %d values, average is %g\n"</span>,(<span class="keywordtype">int</span>)values_len,average);
<a name="l00109"></a>00109
<a name="l00110"></a>00110 <a name="a6"></a><a class="code" href="group__grib__handle.html#g0e4b2585f22247c49b930c1579257677" title="Frees a handle, also frees the message if it is not a user message.">grib_handle_delete</a>(h);
<a name="l00111"></a>00111
<a name="l00112"></a>00112 fclose(in);
<a name="l00113"></a>00113 <span class="keywordflow">return</span> 0;
<a name="l00114"></a>00114 }
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