Resend to the mailing list<br><br><div class="gmail_quote">---------- Forwarded message ----------<br>From: <b class="gmail_sendername">Yingqi Tang</b> <span dir="ltr"><<a href="mailto:anakintang@gmail.com">anakintang@gmail.com</a>></span><br>
Date: Thu, May 17, 2012 at 12:03 PM<br>Subject: Re: [gdal-dev] Can OGR WFS driver take advantage of WFS Server streaming?<br>To: Even Rouault <<a href="mailto:even.rouault@mines-paris.org">even.rouault@mines-paris.org</a>><br>
<br><br>How can I do below through GDAL Python API?<div><br></div><div><div class="im">wget -O - "<a href="http://testing.deegree.org/deegree-" target="_blank">http://testing.deegree.org/deegree-</a><br>wfs/services?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetFeature&TYPENAME=app:Springs"<br>
| ogrinfo -ro -al -q /vsistdin/ <br><br></div><div><div class="h5"><div class="gmail_quote">On Thu, May 17, 2012 at 9:47 AM, Even Rouault <span dir="ltr"><<a href="mailto:even.rouault@mines-paris.org" target="_blank">even.rouault@mines-paris.org</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><br>
> > 2. Does the GML driver take url pointing to a GML?<br>
><br>
> It can work with /vsicurl/<a href="http://something" target="_blank">http://something</a>, provided that the server allows<br>
> partial downloading of arbitrary ranges of bytes within the file, which is<br>
> rarely the case with GetFeature() requests.<br>
><br>
> In theory the WFS driver could be improved to use the capability of the GML<br>
> driver to read chunk by chunk, but there is some work to make that happen.<br>
> This would probably require a /vsicurl_streaming/ virtual file system where<br>
> basically only Read() requests would be available, thus not requiring the<br>
> server to have download range capabilities.<br>
<br>
</div>Before considering the effort of implementing /vsicurl_streaming/ , I've<br>
improved a few things in the GML driver in trunk that allows to parse a GML<br>
stream that is a WFS GetFeature response document.<br>
<br>
So you can now try the following command on Linux :<br>
<br>
wget -O - "<a href="http://testing.deegree.org/deegree-" target="_blank">http://testing.deegree.org/deegree-</a><br>
wfs/services?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetFeature&TYPENAME=app:Springs"<br>
| ogrinfo -ro -al -q /vsistdin/<br>
<br>
or<br>
<br>
wget -O - "<a href="http://testing.deegree.org/deegree-" target="_blank">http://testing.deegree.org/deegree-</a><br>
wfs/services?SERVICE=WFS&VERSION=1.1.0&REQUEST=GetFeature&TYPENAME=app:Springs"<br>
| ogr2ogr springs.shp /vsistdin/<br>
<br>
(or instead of "wget -O -", you can use "curl" depending on what is installed<br>
on your machine)<br>
</blockquote></div><br></div></div></div>
</div><br>