[HOT] ideas on creating a dedicated server for Philippine topomap rectification

maning sambale emmanuel.sambale at gmail.com
Fri Feb 18 09:13:16 GMT 2011


This is what Schuyler's script does.  One issue we found out is that
the geographic coordinates on the map corners are in "Tansverse
Mercator Clark 1866 Luzon Datum",  if there is way to georegister the
image into the above CRS and then reproject later on to wgs84, then
that would be a good option as well.

On Fri, Feb 18, 2011 at 3:57 PM, Nick McWilliam
<nmcwilliam at mapaction.org> wrote:
> Hi all,
>
> As far as georegistration is concerned, there could be a short-cut here:
> most topographic map series are arranged on a regular grid - i.e. as tiles -
> whether with reference to geographical coordinates (e.g. each map is 15 x 15
> mins) or a local UTM-type system (e.g. 40 x 40 km).
>
> If this is the case here, then a script can be written to generate a series
> of JGW (or TFW, etc) files. For a map series of the same scale, the only
> variable in the output is the top left corner coordinate; the pixel size and
> image orientation remain constant.
>
> The method relies on the map filenames being somehow tied to their position
> on the map grid: quite often this is the case anyway, through the map tiling
> system. If not, a look-up table can be used, or the files renamed, though
> that may be a manual process: it can be as simple as 01A,01B,01C,02A,02B...
>
> Another assumption is that map scans are 'collar clipped', i.e. the scan
> includes only the geographical extent of the map, and not the map margins.
> This would be highly desirable in any case if setting up a WMS.
>
> Nick.
>
>
> Nick McWilliam
> MapAction GIS Coordinator
> nmcwilliam at mapaction.org / skype nickmcw / www.mapaction.org
> mobile +44 77 7379 7471 / office +44 1494 865 031
>
>
> Quoting maning sambale <emmanuel.sambale at gmail.com>:
>
>> At the moment I have 10 GB of jpgs.  But this is only the first batch.
>>  The whole PH has ~900 toposheets on the average, each sheet is around
>> 50 MB.  So that's around 50 GBs of raw images.  I'm not sure how to
>> calculate the full disk requirements considering map warper, wms and
>> tms.
>>
>> But I think we can start from your offer. :)
>>
>> Thanks!
>>
>>
>> On Fri, Feb 18, 2011 at 1:51 PM, Milo van der Linden <milo at dogodigi.net>
>> wrote:
>>>
>>> How much space do you need?
>>>
>>> I got about 6 Tb on my dedicated servers left plus the ability to host
>>> the
>>> warping service itself.
>>>
>>> 2011/2/18 maning sambale <emmanuel.sambale at gmail.com>
>>>>
>>>> Hi,
>>>>
>>>> This is Maning from the Philippines.  Last year we had a HOT
>>>> activation as a response to flooding in Northern Philippines [1].
>>>> Part of what we did is to rectify several 1:50k  and 1:250K old
>>>> topographic maps which were hosted in NYPL's Relief Map Warper [2]
>>>> [3].  Moreover, Schuyler Earl provided another WMS for the same set of
>>>> maps in the telascience [4].  He used a really cool script to quickly
>>>> rectify the maps using the four corners.
>>>>
>>>> One group saw the initiative and is interested to donate thousands of
>>>> un-rectified topographic maps in their collection.  What I intend to
>>>> do is to crowdsource the rectification.  Once rectified, we intend to
>>>> create a separate public tms/wms for anyone to use. On my end I intend
>>>> to use them for any future HOT activation in the country and OSM
>>>> editing.
>>>>
>>>> I asked Tim (developer of the Map Warper) if we can upload more topos
>>>> in NYPL, but the existing service have very limited disk space.  I'm
>>>> asking the group for help in creating a dedicated webservice to upload
>>>> and crowdsource the rectification of the maps.  I can maintain the
>>>> service in the long term and hopefully encourage other data holders to
>>>> provide more scanned topos.
>>>>
>>>> Any ideas on how to do this is very much appreciated.
>>>>
>>>> [1] http://wiki.openstreetmap.org/wiki/Philippines_Tropical_Storm_2010
>>>> [2] http://maps.nypl.org/relief/layers/12
>>>> [3] http://maps.nypl.org/relief/layers/13
>>>> [4]
>>>>
>>>> http://hyperquad.telascience.org/cgi-bin/mapserv?map=/data/sderle/ph50k/ph50k.map&FORMAT=image/jpeg&VERSION=1.1.1&SERVICE=WMS&REQUEST=GetMap&Layers=ph50k&
>>>> --
>>>> cheers,
>>>> maning
>>>> ------------------------------------------------------
>>>> "Freedom is still the most radical idea of all" -N.Branden
>>>> wiki: http://esambale.wikispaces.com/
>>>> blog: http://epsg4253.wordpress.com/
>>>> ------------------------------------------------------
>>>>
>>>> _______________________________________________
>>>> HOT mailing list
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>>>> http://lists.openstreetmap.org/listinfo/hot
>>>
>>>
>>
>>
>>
>> --
>> cheers,
>> maning
>> ------------------------------------------------------
>> "Freedom is still the most radical idea of all" -N.Branden
>> wiki: http://esambale.wikispaces.com/
>> blog: http://epsg4253.wordpress.com/
>> ------------------------------------------------------
>>
>> _______________________________________________
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>>
>
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-- 
cheers,
maning
------------------------------------------------------
"Freedom is still the most radical idea of all" -N.Branden
wiki: http://esambale.wikispaces.com/
blog: http://epsg4253.wordpress.com/
------------------------------------------------------



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