[OSM-talk] who moved Mumbai?

Shekhar Krishnan shekhar at crit.org.in
Sun Jul 6 19:43:22 BST 2008


I have also imported the road network layer from the Mumbai Freemap and here
is the WMS URL:

http://mumbai.freemap.in/wms.cgi?srs=epsg:4326&format=image/png&request=GetMap&service=WMS&version=1.1.1&layers=road_net_line_4326

Good for comparing to AND's road network. ;-)


S.K.

2008/7/6 Shekhar Krishnan <shekhar at crit.org.in>:

> I spent today attempting to grapple with these issues, with some success.
> We've reprojected the WMS into wgs84 (EPSG:4326) from UTM 43N (EPSG:32643)
> by reprojecting the shape files using ogr2ogr. This fixed the WMS problem,
> and I have succesfully loaded these URLs for different layers from the
> Mumbai Freemap in JOSM:
>
> Buildings (Polygons)
>
> http://mumbai.freemap.in/wms.cgi?srs=epsg:4326&format=image/jpeg&request=GetMap&service=WMS&version=1.1.1&layers=building_polygon_4326
>
> Building Outlines (Lines)
>
> http://mumbai.freemap.in/wms.cgi?srs=epsg:4326&format=image/jpeg&request=GetMap&service=WMS&version=1.1.1&layers=building_line_4326
>
> Municipal Land Use Reservations (Polygons)
>
> http://mumbai.freemap.in/wms.cgi?srs=epsg:4326&format=image/jpeg&request=GetMap&service=WMS&version=1.1.1&layers=reserved_polygon_4326
>
> There are several other layers in http://mumbai.freemap.in that are not
> here yet, and I will work on grouping and styling them so there is only one
> for buildings and another for road and rail networks and send around new
> links. A quick glance at the results in OSM shows that as reported, with the
> AND data on OSM right now, everything has been moved east and north, though
> this is not consistent and in Central Mumbai the offset seems to becomes
> less.
>
> This raises the question of what to do generally about Mumbai in OSM. While
> a WMS overlay looks nice and can be traced by volunteers with a great deal
> of time and effort, I am more interested in directly loading these shape
> files into JOSM and supplementing or replacing the AND data with our Mumbai
> Freemap layers. I am happy to share these shape files with anyone in the OSM
> community who might be able to lend a hand using osmlib, ruby-shapefile,
> gml2osm, or any other method.
>
> A correction to Mikel: the third dataset which you mentioned we have from
> the Govt of Maharashtra PWD is not of Mumbai, but of the rest of the state,
> and contains the entire road network, all village names and maps, and
> district boundaries for Maharashtra. These are also shape files with their
> own pecularities.
>
> I've had issues both with JSOM and the WMS plugin which I'll also note
> here. I'm a newcomer to both, so any help is appreciated. Downloading data
> for Mumbai from OSM and from local OSM instances such as
> http://demo.binyasit.com:3000/ almost always returns only a snippet of the
> area which I select from the permalink. I'm not sure why, sometimes I get
> the fulll boundaries of Greater Mumbai and then a handful of nodes.
>
> Also, the WMS plugin is not very good at saving changes made to new
> entries, which often revert to the previous saved entry after restarting
> JSOM. This has made it difficult to keep track of which WMS URL is being
> called as the menu is not refreshed after saving a URL and restarting JSOM.
> The other issue, which Chippy raised, is the lack of UTM support in the WMS
> plugin which should be addressed as we would rather use our UTM projection
> fof maximum accuracy.
>
> Thanks for the help and support!
>
> Best,
>
>
> Shekhar
>
> 2008/7/6 Tim Waters (chippy) <chippy2005 at gmail.com>:
>
> UTM which EPS:32643 appears to be, could be implemented within the
>> wmsplugin.
>>
>> The WMSplugin uses some classes from jcoord, to convert from OSGB
>> (what the NPE wms server uses) to wgs84. (OSGB is itself Transverse
>> Mercator too)
>>
>> Looking at the jcoord package, it also has classes to convert from UTM
>> zones also :
>> http://www.jstott.me.uk/jcoord/api/1.1-b/uk/me/jstott/jcoord/UTMRef.html
>> So I'd think the wmsplugin could be hacked to get it working
>> reasonably easily.
>>
>> Regards,
>>
>> Tim
>>
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>>
>
>
>
> --
>
> Shekhar Krishnan
> 9 Supriya, 2nd Floor
> Plot 709, Parsee Colony Road no.4
> Dadar, Mumbai 400014
> India
> 
> http://web.mit.edu/shekhar
> http://heptanesia.net
> http://bombayology.net
>



-- 

Shekhar Krishnan
9 Supriya, 2nd Floor
Plot 709, Parsee Colony Road no.4
Dadar, Mumbai 400014
India

http://web.mit.edu/shekhar
http://heptanesia.net
http://bombayology.net
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