What is Georeferencer?
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What is the online service Georeferencer.org?
It is a tool designed to bookmark, georeference and annotate high-resolution images
which you find on the web.
It is a collaborative web 2.0 online service
which you can use
and
it allows crowdsourcing
of
georeferencing without installing any software
on your desktop - just from the webbrowser
better than to describe it is to see it. If you go to Georeferencer.org
you find there an on-line service which is used this way:
you drag the bookmarklet into your bookmark bar in the web browser
and then when you are browsing Internet and
you find some interesting map, which can be also a high resolution map,
or an image from Flicker or Wikipedia
as well as
an image published on a website of a library.
In this case it is an old map
from an map seller
published online in a Zoomify format.
That you click on the bookmarklet
and the bookmarklet
manages to find in the website the high resolution image
and displays it in the Georeferencer interface.
The Georeferencer is able to do
a bit more with the map
so
when you click on the georeferencing
you can assign control points.
So simply find on the old map
a place which
has not been changed in the time
click on that place and click on the modern map
and point this way the place
We were working pretty hard
on improving this interface so it is usable by retired people and kids.
It is straightforward. There are no "modes", you don't have to switch to the editing mode and back.
It is optimized for the number of clicks as well.
You can edit the points pretty user-friendly
and you can also crop the map, select the border,
which is not part of the map
and should be cut away
quite..
..easily. I hope it is natural. You can try it and send me a feedback.
Through the magical red "Feedback" button
on the side, which you can use anytime.
We will be very glad for feedback.
From the control points the system automatically generates
KML metadata
so the original image
can appear on the correct location in Google Earth
just by you choosing this three or more points
in the website
We are able to generate the metadata Google Earth needs
to display
the image
on top of terrain in Google Earth inside of your webbrowser.
We have implemented also a cloud service
for providing WMS. In fact
we provide
right now three kinds of WMS services for every map
every revision of the map.
The system keeps track of all the modifications. It is like Wikipedia
or similar services. When somebody comes and click the control points we save everything
what was done in the system.
All people have to log-in
and if you see that somebody did something wrong you can
go back in time and restore the original version.
If you are not satisfied with how the georeference was done
and you think it should be done differently
you can just log-in into the online system
and do it yourself.
You get your own WMS service for the map
and it all runs just as a service.
So, we are providing three WMS services
for every revision
of the georeference for an old map.
This is a next tool:
the MapAnalyst visualization
especially if you provide more points then I did for this map,
it can gives you
the accuracy analyze, or visualization of the cartometric accuracy of the map
that shows in which way the map was not accurate
what are probably the problems
where the cartographer used
places which were measured and where not.
All the math behind
is based on the open-source MapAnalyst application.
