<div dir="ltr">Sorry, looks like I can't include the file with the image in it. If you run the steps I sent, and create a file called "test.tif", you can dump the text below in an editor and save it to a file as "test.kml" in the same directory as "test.tif" .<br>
<br><GroundOverlay><br><description>test.tif</description><br><name>test.tif</name><br><visibility>0</visibility><br><open>1</open><br><Icon><br><href>test.tif</href><br>
</Icon><br><drawOrder>0</drawOrder><br><LatLonBox><br><north> 48.3206090</north><br><south> 41.8368598</south><br><west> -79.2180023</west><br><east> -62.5439783</east><br>
</LatLonBox><br></GroundOverlay><br>--<br><br><div class="gmail_quote">On Thu, Oct 9, 2008 at 4:54 PM, Roger André <span dir="ltr"><<a href="mailto:randre@gmail.com">randre@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div dir="ltr">Hi James,<br><br>Spent some time trying to gereference the file using the corner coords that you provided, but had absolutely no luck. One thing you could try that might work better is to defin some Ground Control Points. Basically you can pick features on the image that you can identify on another map, and record the lon lat and pixel x y positions. Then you use gdal_translate to assign the GCP's to the image, and finally use gdalwarp to warp the image to fit the GCP points.<br>
<br>Here are some rough ones that I used on the sample you sent me:<br>- gdal_translate -gcp 171 320 -76.864698 43.943184 -gcp 818 23 -70.410805 47.178880 -gcp 804 473 -69.829644 43.706997 flight_chart.tif gcp_flight_chart.tif<br>
<br>- gdalwarp -s_srs "EPSG:4326" -t_srs "EPSG:4326" gcp_flight_chart.tif test.tif<br><br>I've attached a KMZ file of this, you can see that it's not perfect, but if you work with the higher resolution image, and assign more GCP's it should start to bet pretty close.<br>
<br>To go immediately to spherical mercator, you'll have to convert the points you find into spherical mercator coordinates, and then use EPSG:900913 instead of 4326.<br><br>Roger<br><font color="#888888">--<br><br><br>
</font><div class="gmail_quote"><div class="Ih2E3d">
On Thu, Oct 9, 2008 at 9:54 AM, James Trimble <span dir="ltr"><<a href="mailto:jimmit.t@gmail.com" target="_blank">jimmit.t@gmail.com</a>></span> wrote:<br>
</div><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;"><div><div></div><div class="Wj3C7c"><div dir="ltr">** I apologize if this message appears more than once, but it does not look like it's going through for me **<br>
<br>Hi, I am trying to georeference and reproject an FAA Enroute IFR chart. You can find the pdf version of this chart at <a href="http://goog_1223485636161/" target="_blank">http://www.jamestrimble.info/US</a><div style="display: inline; padding-right: 16px; width: 16px; height: 16px;">
L32 31 JUL 08.pdf</div><a href="http://www.jamestrimble.info/US%20L32%2031%20JUL%2008.pdf" target="_blank"></a><div style="display: inline; padding-right: 16px; width: 16px; height: 16px;"> </div> <br>
I use The Gimp to convert the pdf to png.<br><br>The parameters are <br>L-32 1:14NM (1020787)<br>GP 47 56 09.6N 063 04 30.3W (Upper Right)<br>GP 46 02 46.4N 079 29 47.0W (Upper Left)<br>GP 41 48 34.9N 078 00 33.5W (Lower Left)<br>
GP 43 35 36.2N 062 37 08.3W (Lower Right)<br>
<br>Top Standard Parallel 45 00 00N<br>Bottom Standard Parallel 33 00 00N<br>Central Meridian 95 00 00W<br>Origin 39 00 00N 95 00 00W<br><br>Datum = North American Datum of 1983<br><br>Ultimately, I'd like to have this map in a mercator projection to overlay with google maps.<br>
<br>The commands I tried to use are :<br><br>gdal_translate -a_srs
"+proj=lcc +lat_1=45.0 +lat_2=33.0 +lat_0=39.0 +lon_0=95.0
+datum=NAD83" -a_ullr -79.4964 46.0462 -62.6190 43.5934 -of GTiff -co
"INTERLEAVE=PIXEL" "C:\Documents and Settings\James\Desktop\US L32 31
JUL 08_CROPPED.png" .\USL32.tiff<br>
<br>gdalwarp -of GTiff -co "INTERLEAVE=PIXEL" -s_srs "+proj=lcc
+lat_1=45.0 +lat_2=33.0 +lat_0=39.0 +lon_0=95.0 +datum=NAD83" -t_srs
"+proj=merc +datum=NAD83" .\USL32.tiff .\USL32_MERC.tiff<br>
<br>I would really appreciate some help on how to do this correctly.<br><br>Thank you very much,<br><font color="#888888"><font color="#888888">James</font></font></div>
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