GDAL runs on most platforms, including Windows, so I'm not sure where you get the idea it only runs on Macs! The easiest way of getting installed on your machine is to download OSGeo4W, which is an installer for all manner of desktop GIS goodness, from which you can just choose GDAL/OGR.
Once you've done that, you can use the command line tool gdalwarp
to reproject the images:
gdalwarp -t_srs EPSG:3857 -s_srs EPSG:9802 -r cubic -co "TILED=YES" input1.tif input2.tif ... input30.tif output.tif
Where EPSG:3857 is shorthand for the "Web Mercator" projection (thanks Sean!), and EPSG:9802 is the shorthand for the Lambert projection. You may need to use a different sampling algorithm instead of cubic, it depends on the sort of data you've got, and how it looks when it is warped. Specifying all the source images in one command line will avoid unsightly seams between the original images. the "TILED=YES" is sensible for almost any geo rasters to speed up access and display. See here for explanation of the parameters.
To split the image into tiles, you can use gdal2tiles.py (which you'll need to install Python, but that can be done with the OSGeo4W installer).
Addendum
It ocurred to me last night that you would need to specify the two lines of parallel and the central meridian of your source images on the command line, just using EPSG:9802 won't cut the mustard if that metadata isn't already in the source images. If that is the case, you'll need to change the -s_srs parameter to something like this:
-s_srs "+proj=lcc +lon_0=110 +lat_1=25 +lat_2=47 +datum=WGS84"
Where +lon_0
is the longitude of the central meridian, +lat_1
is the upper standard parallel, and +lat_2
is the lower standard parallel. If the images you're warping are of the same series, these values are likely to be the same for each image, but it is worth checking them first.
If you're unsure about how these projections work, you could do worse than looking here for an explanation.
A good point made by Rene W.
Here is the answer:
add +no_defs to your first example in order to avoid unwanted default values
about this part: +a=6367470 +b=6367470 +ellps=sphere +datum=WGS84
+datum=WGS84 is a shorthand for: +ellps=WGS84 +towgs84=0,0,0.
You already have +ellps=sphere. Your reference surface cannot be a shpere
and the WGS84 ellipsoid at the same time. As you already have +a=6367470
and +b=6367470, you should drop both +ellps=sphere and +datum=WGS84`
in case of doubts, use cs2cs -v for more info about which parameters
are actually takes, and which are ignored
Hermann
and
The default values of lat_1 and lat_2 are 33 and 45, so in your first
example you had +lat_1=46.244 +lat_2=45 which is not what you intended.
The second example does what you wanted.
Charles
Best Answer
If the chart shows US location, it's not using a state plane zone, and I can't think of another US-based CRS that has those standard parallel values (46deg 40min and 49deg 20min). With the knowledge that the chart's area of interest is in Canada, I couldn't find any existing CRS that match. I think you'll have to create a custom definition. The central meridian may be the longitude at the center of the map.
Here's a link to the QGIS 1.8 help on projections which discusses creating a custom definition near the bottom of the page.
I don't have QGIS to check this but there have been several other questions here about adding a custom projected coordinate reference system. Cribbing from one, here's a PROJ.4 line for a North American Albers definition:
Now let's modify it to match yours:
You'll have to fill in the lat_0 and lon_0 (latitude and longitude of origin, try the map's center?).