<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1">
<style type="text/css" style="display:none;"><!-- P {margin-top:0;margin-bottom:0;} --></style>
</head>
<body dir="ltr">
<div id="divtagdefaultwrapper" style="font-size:12pt;color:#000000;background-color:#FFFFFF;font-family:Calibri,Arial,Helvetica,sans-serif;">
<p>Hi Jose,</p>
<p><br>
</p>
<p>Thanks for the quick reply.</p>
<p><br>
</p>
<p>What do you mean "be geo-referenced"? What I'm thinking is to use these tools to convert a 360 panorama picture, such as <a href="https://upload.wikimedia.org/wikipedia/commons/3/35/Space_Needle_360_Panorama.jpg" id="LPlnk119911" title="https://upload.wikimedia.org/wikipedia/commons/3/35/Space_Needle_360_Panorama.jpg
Cmd+Click or tap to follow the link">https://upload.wikimedia.org/wikipedia/commons/3/35/Space_Needle_360_Panorama.jpg</a>,
which is an equidistant cylindrical projection, to other type of projection, which keeps same quality but with smaller size. Thus I can save some storage spaces. In this case, these 360 picture doesn't have any geo-referenced data. Can I still use these tools? </p>
<p><br>
</p>
<p><img src="https://upload.wikimedia.org/wikipedia/commons/3/35/Space_Needle_360_Panorama.jpg"></p>
<p></p>
<br>
<br>
<div style="color: rgb(0, 0, 0);">
<hr tabindex="-1" style="display:inline-block; width:98%">
<div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" color="#000000" style="font-size:11pt"><b>From:</b> proj-bounces@lists.maptools.org <proj-bounces@lists.maptools.org> on behalf of Jose Gonçalves <jagoncal@gmail.com><br>
<b>Sent:</b> Tuesday, May 24, 2016 11:03 PM<br>
<b>To:</b> PROJ.4 and general Projections Discussions<br>
<b>Subject:</b> Re: [Proj] convert from Equidistant Cylindrical to Eckert I</font>
<div> </div>
</div>
<div>
<div dir="ltr">
<div>
<div>
<div>Hi<br>
</div>
You can transform your image with the following command line:<br>
<br>
gdalwarp -s_srs "+ellps=WGS84 +proj=eqd" -t_srs "+ellps=WGS84 +proj=eck1" in.tif out.tif<br>
<br>
</div>
The input image must be georeferenced in the equidistant cylindrical projection, with units in meters. See page
<a href="http://www.gdal.org/gdalwarp.html" id="LPlnk700781">http://www.gdal.org/gdalwarp.html</a>. Other important options are -r, -te and -tr.
<div id="LPBorder_GT_14641324935210.7110090681817383" style="margin-bottom: 20px; overflow: auto; width: 100%; text-indent: 0px;">
<table id="LPContainer_14641324935200.46404356020502746" cellspacing="0" style="width: 90%; background-color: rgb(255, 255, 255); position: relative; overflow: auto; padding-top: 20px; padding-bottom: 20px; margin-top: 20px; border-top-width: 1px; border-top-style: dotted; border-top-color: rgb(200, 200, 200); border-bottom-width: 1px; border-bottom-style: dotted; border-bottom-color: rgb(200, 200, 200);">
<tbody>
<tr valign="top" style="border-spacing: 0px;">
<td id="TextCell_14641324935200.09451112034730613" colspan="2" style="vertical-align: top; position: relative; padding: 0px; display: table-cell;">
<div id="LPRemovePreviewContainer_14641324935210.5110380863770843"></div>
<div id="LPTitle_14641324935210.5333282561041415" style="top: 0px; color: rgb(0, 120, 215); font-weight: normal; font-size: 21px; font-family: wf_segoe-ui_light, 'Segoe UI Light', 'Segoe WP Light', 'Segoe UI', 'Segoe WP', Tahoma, Arial, sans-serif; line-height: 21px;">
<a id="LPUrlAnchor_14641324935210.8752200847957283" href="http://www.gdal.org/gdalwarp.html" target="_blank" style="text-decoration: none;">GDAL: gdalwarp</a></div>
<div id="LPMetadata_14641324935210.9733305182307959" style="margin: 10px 0px 16px; color: rgb(102, 102, 102); font-weight: normal; font-family: wf_segoe-ui_normal, 'Segoe UI', 'Segoe WP', Tahoma, Arial, sans-serif; font-size: 14px; line-height: 14px;">
www.gdal.org</div>
<div id="LPDescription_14641324935210.7120281341485679" style="display: block; color: rgb(102, 102, 102); font-weight: normal; font-family: wf_segoe-ui_normal, 'Segoe UI', 'Segoe WP', Tahoma, Arial, sans-serif; font-size: 14px; line-height: 20px; max-height: 100px; overflow: hidden;">
image reprojection and warping utility. SYNOPSIS. Usage: gdalwarp [--help-general] [--formats] [-s_srs srs_def] [-t_srs srs_def] [-to "NAME=VALUE"] [-order n | -tps ...</div>
</td>
</tr>
</tbody>
</table>
</div>
<br>
<br>
</div>
Regards<br>
<div>
<div>José Gonçalves<br>
</div>
<div><br>
</div>
</div>
</div>
<div class="gmail_extra"><br>
<div class="gmail_quote">2016-05-24 23:16 GMT+01:00 Wang Leslie <span dir="ltr"><<a href="mailto:wqyuwss@hotmail.com" target="_blank">wqyuwss@hotmail.com</a>></span>:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex; border-left:1px #ccc solid; padding-left:1ex">
Hi Norman, Dann,<br>
<br>
Thanks for quick reply. It would be highly appreciated for one sample command on these tools to achieve my goal.<br>
<br>
Best Regards<br>
Leslie<br>
<br>
________________________________________<br>
From: <a href="mailto:proj-bounces@lists.maptools.org">proj-bounces@lists.maptools.org</a> <<a href="mailto:proj-bounces@lists.maptools.org">proj-bounces@lists.maptools.org</a>> on behalf of Norman Vine <<a href="mailto:nhv@cape.com">nhv@cape.com</a>><br>
Sent: Tuesday, May 24, 2016 7:20 AM<br>
To: PROJ.4 and general Projections Discussions<br>
Subject: Re: [Proj] convert from Equidistant Cylindrical to Eckert I<br>
<div class="HOEnZb">
<div class="h5"><br>
Hello Leslie<br>
<br>
I suggest using <a href="http://www.gdal.org/gdalwarp.html" rel="noreferrer" target="_blank">
http://www.gdal.org/gdalwarp.html</a> todo this<br>
<br>
To avoid the speckling that Daan mentions you want to loop over the new image<br>
pixels and do the inverse projection to find the pixel value in the original image<br>
<br>
gdalwarp takes care of this for you and is built on top of the proj library<br>
<br>
Norman<br>
<br>
> On May 24, 2016, at 3:05 AM, <a href="mailto:strebe@aol.com">strebe@aol.com</a> wrote:<br>
><br>
> Hello Leslie.<br>
><br>
> Your procedure will work. The results will be heavily aliased, which will look like speckling. Some values of (x₁, y₁) will be empty unless the destination map is considerably smaller than the source image.<br>
><br>
> Regards,<br>
> — daan Strebe<br>
><br>
><br>
><br>
> -----Original Message-----<br>
> From: Wang Leslie <<a href="mailto:wqyuwss@hotmail.com">wqyuwss@hotmail.com</a>><br>
> To: proj <<a href="mailto:proj@lists.maptools.org">proj@lists.maptools.org</a>><br>
> Sent: Mon, May 23, 2016 7:37 am<br>
> Subject: [Proj] convert from Equidistant Cylindrical to Eckert I<br>
><br>
> Dear all,<br>
><br>
> I'm new to this tool, and hope to get some advise here.<br>
><br>
> I'm thinking to use your tool to convert a map picture which is based on Equidistant Cylindrical, to another picture based on Eckert I. Since both of them are 2 dimension only (x,y), what I'm gonna to do is:<br>
> - Use proj command to calculate the new mapped coordinate (x1, y1)<br>
> - Set new pixel value at (x1, y1) using original pixel value (x,y)<br>
> - loop for all pixel at original Equidistant Cylindrical picture<br>
><br>
> So can you please help me confirm if one idea can work or not? If yes, what should command line look like? Thanks.<br>
><br>
> Best Regards<br>
> Leslie Qi Wang<br>
> _______________________________________________<br>
> Proj mailing list<br>
> <a href="mailto:Proj@lists.maptools.org">Proj@lists.maptools.org</a><br>
> <a href="http://lists.maptools.org/mailman/listinfo/proj" rel="noreferrer" target="_blank">
http://lists.maptools.org/mailman/listinfo/proj</a><br>
> _______________________________________________<br>
> Proj mailing list<br>
> <a href="mailto:Proj@lists.maptools.org">Proj@lists.maptools.org</a><br>
> <a href="http://lists.maptools.org/mailman/listinfo/proj" rel="noreferrer" target="_blank">
http://lists.maptools.org/mailman/listinfo/proj</a><br>
<br>
_______________________________________________<br>
Proj mailing list<br>
<a href="mailto:Proj@lists.maptools.org">Proj@lists.maptools.org</a><br>
<a href="http://lists.maptools.org/mailman/listinfo/proj" rel="noreferrer" target="_blank">http://lists.maptools.org/mailman/listinfo/proj</a><br>
_______________________________________________<br>
Proj mailing list<br>
<a href="mailto:Proj@lists.maptools.org">Proj@lists.maptools.org</a><br>
<a href="http://lists.maptools.org/mailman/listinfo/proj" rel="noreferrer" target="_blank">http://lists.maptools.org/mailman/listinfo/proj</a></div>
</div>
</blockquote>
</div>
<br>
</div>
</div>
</div>
</div>
</body>
</html>