<div>Hi Frank, </div>
<div> </div>
<div>I suspect that what is happening is that the VMAP data source is being opened for writing instead of for reading. After debugging here is why I've come to this conclusion. </div>
<div> </div>
<div><font size="2">
<p>OGRDataSource* pOGRDataSource = OGRSFDriverRegistrar::Open(char *ptrDataSrc); </p>
<p>This in turn goes through all the drivers until it comes to. </p><font color="#0000ff" size="2">
<p>int</p></font><font size="2"> OGROGDIDataSource::Open</font>
<p>So as I step through this code, with the debugger everything works like I would expect it to work. </p>
<p>Then I come to this </p><font color="#008000" size="2">
<p>/* -------------------------------------------------------------------- */</p>
<p>/* If an explicit layer was selected, just create that layer. */</p>
<p>/* -------------------------------------------------------------------- */</p></font><font size="2">
<p>m_poCurrentLayer = NULL;</p></font>
<p>I am selecting an explicit layer so I am bewildered at why this is set to NULL (On a side note I suspect this being null is the root of my problems). </p>
<p>Then after a bunch of else ifs </p>
<p>We call this method </p><font size="2">
<p>IAddLayer( pszLyrName, eFamily );</p>
<p>in ogrogdidatasource.cpp </p>
<p>where we create a new OGRLayer and add it to an array of layers. Now I would think that if we were opening the data source for read we should be fetching the layer as opposed to creating a new one. Creating this new layer would also explain to me why my layer has no features in it. </p>
<p>Thoughts comments Help ?</p>
<p> </p>
<p>Courtney</p></font></font></div>
<div> </div>
<div><br><br> </div>
<div class="gmail_quote">On Wed, Apr 30, 2008 at 10:53 AM, Frank Warmerdam <<a href="mailto:warmerdam@pobox.com">warmerdam@pobox.com</a>> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0.8ex; BORDER-LEFT: #ccc 1px solid">
<div class="Ih2E3d">Courtney Schitka wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px; BORDER-LEFT: #ccc 1px solid">Hi All,<br> As you probably know. I am trying to read. Features from a VMAP data source via code I am developing using GDAL 1.5.1 with OGDI built in.<br>
</blockquote></div>...
<div class="Ih2E3d"><br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px; BORDER-LEFT: #ccc 1px solid">This lead me to the assumption that the code was right and the data was bad. HOWVER when I open the data source + layer via ogrinfo. Everything works like a charm.<br>
</blockquote><br></div>Courtney,<br><br>Honestly, I cannot think of any reason this might be happening other than<br>perhaps that you are using different versions of OGR+OGDI in ogrinfo vs.<br>in your program. I assume that is not the case?<br>
<br>Are you confident it is the same layer you are getting no features from<br>programmatically as you are getting features from with ogrinfo?<br><br>I'm sorry to ask rather basic questions, but I don't know where else to<br>
start given the problems you are seeing.<br><br>Best regards,<br><font color="#888888">-- <br>---------------------------------------+--------------------------------------<br>I set the clouds in motion - turn up | Frank Warmerdam, <a href="mailto:warmerdam@pobox.com" target="_blank">warmerdam@pobox.com</a><br>
light and sound - activate the windows | <a href="http://pobox.com/~warmerdam" target="_blank">http://pobox.com/~warmerdam</a><br>and watch the world go round - Rush | President OSGeo, <a href="http://osgeo.org/" target="_blank">http://osgeo.org</a><br>
<br></font></blockquote></div><br>