[OSM-talk] New Map Warper

Ævar Arnfjörð Bjarmason avarab at gmail.com
Wed Feb 11 16:41:53 GMT 2009

On Wed, Feb 11, 2009 at 1:06 PM, Tim Waters (chippy)
<chippy2005 at gmail.com> wrote:
> I'd like to announce the release of the latest Map Warper image
> rectifier application, designed with OSM in mind.
> http://warper.geothings.net/

Firstly thanks for working on this, it's a very useful application
which makes it very easy to use third-party bitmap maps to import into

> You may have seen or used the older application, this one has got a
> few more bells and whistles, including:
>    * Search for maps.
>    * Users & "MyMaps". (no need to sign up to use it)
>    * Image cropping.
>    * Control Point editing.
>    * Calculation of RMS errors.
>    * Export in different formats.
>    * Activity feeds.
> More info: http://thinkwhere.wordpress.com/2009/02/10/new-map-warper/
> Caveats: It will rescale large images (over 1500x1500), but it also
> makes things work much faster. It is ultra-beta and undergoing active
> development, so expect bugs and things not to work, but for most uses
> it should work fine. Let me know if you encounter any such things.
> If you have any existing WMS links from the older version, they will
> still work and I've also imported the existing maps, and control
> points. If you sign up and want to "own" a map you previously
> uploaded, let me know.
> Features planned include serving the rectified maps as tiles, adding
> tags, making maps private, making the KML export better, and
> incorporating GeoRSS feeds. Again, feel free to drop me a line if you
> have a good idea for a new feature, or if you'd like to hack on it.

These new features are very useful, especially the ones to do with
user accounts, it's nice to have a list of your maps instead of just
adding them to one giant pool.

I think the map rectifier is a bit less intuitive than in the previous
version. I used to be able to double click on either map which would
add a new rectification point and then do the same with the other map,
but now one has to switch between the Add point/Move point/Move map
tools to move around the map. This has the advantage of being able to
double click on the map in move mode without adding points (and
probably something else I'm missing). But switching between the
different modes took me bit longer using this method.

Also, being able to download GeoTiff from the application is a very
useful feature, but does it also support GeoTiff uploads? That would
enable moving maps between installations and using this as a easy to
set up WMS for misc GeoTiff files.

The biggest disadvantage of this tool is still being limited by the
size of maps you can upload. I have several ~6000x~5000 pixel maps I'd
like to have access to over WMS, each around 12 MB[1]. Is there any
reason for this limitation other than preventing the application from
taking over resources on your server? Or is it a limitation of some
library you're working with?

> Incidentally, what do we think about using Google's Satellite View for
> helping to rectify our maps?
> [...]

Ask the lawyer droids over on legal-talk ?:)

1. http://commons.wikimedia.org/wiki/Category:Uppdráttr_Íslands_(1844)

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