[OSM-talk] JOSM and landsat shifting
frederik at remote.org
Thu Feb 22 10:02:33 GMT 2007
> Ditto here. I have found with some fiddling - permutations of
> unclicking/clicking the landsat move button, selecting one landsat
> layer after another - I can get subsequent layers to move but haven't
> found a consistent pattern I can report. I've also found that if
> you have two overlapping landsat images, only the first will
> move. If you drag the first one off to one side rather than deleting
> it, you can get the second to move.
This is still very much unchanged in the WMSplugin (which I encourage
everybody to use instead of the Landsat plugin - WMSplugin can do
everything that landsat could and then some). With the possible
exception that the WMSplugin puts all landsat images onto the same
Better control over aligning individual tiles is already on the to-do
list for that plugin. (The original landsat plugin was written by
Nick Whitelegg, then Tim "Chippy" - http://thinkwhere.wordpress.com/
- did the more general WMS plugin, and I have contributed a bit to it.)
> 1) Change the behaviour so that it you download one landsat image and
> re-align it, all subsequent image downloads are similarly
> re-adjusted. If you do more adjustment, if affects all images en
Not necessarily good, since inaccuracies may also stem from the
process used to cut and resize the image - images downloaded on
different zoom levels may require different adjustments!
> 4) Allow local caching of images for re-use in a future edit
> sessions. This would be of great benefit to dial-up users.
Local caching of downloaded images is also on my wish list and if
nobody else does, I'll put that into the WMS plugin some time soon.
It will however be a bit painful to find a good way of selecting
cached images to display, especially as non-landsat WMS servers (e.g.
my own "Yahoo WMS") may deliver wildly different pictures depending
on the size of the region you request.
> and future development direction;
> 5) Extend the whole concept to generally load images from hard disk
> and display them as underlays. I realize this involves significant
> work in putting in a geo-referencing and perhaps orthorectication
> step - I think there is already someone working on this separately?
There's the Metacarta map rectifier which I have used in conjunction
with the WMS plugin, and it works quite well. You upload your map
image to Metacarta, then rectify it using a Google map or satellite
picture as a reference, and afterwards you can query the Metacarta
WMS server directly from the WMS plugin.
Metacarta used to say that anything you upload can be accessed by
anyone, but they now have a (yet undocumented) feature where you can
register an account with them, then upload your image as "private".
The WMS plugin will then automatically ask for username and password
when downloading an image from there (unfortunately if you click on
"remember password" it will overwrite your credentials for the OSM
server, you cannot have it remember both it seems).
In theory any map used for OSM work should be "public" anyway, but
there may be situations where you have the right to use the data
displayed on a map, but not the right to distribute/publish the map
as a whole, that's where the "private" feature is handy.
Frederik Ramm ## eMail frederik at remote.org ## N49°00.09' E008°23.33'
More information about the talk