Digitising Ward Maps of Bhubaneswar, Odisha. [Work in Progress] Information about Bhubaneswar

[Pratyush Mohapatra]

Link to the geojson file:
https://github.com/Ativerc/GeoData/blob/master/BBSR_Wardmap_v0.1.geojson

If you have any suggestions, please let me know.


Created by following the steps given here:
http://datameet.org/2016/08/12/guide-on-digitizing-static-maps/

So thanks NikhilVJ for that (why don't you put your contact links on datameet's website?).

About Bhubaneswar:

Bhubaneswar is the capital of Odisha. Its local urban governing body is called Bhubaneswar Municipal Corporation (BMC). https://en.wikipedia.org/wiki/Bhubaneswar_Municipal_Corporation

www.bmc.gov.in

I will be posting more information soon.

[Devdatta Tengshe]

Hi Pratyush,

After you shared the link on the Slack channel, I scraped some of the data, directly from the ArcGIS backend.

I've shared it at the following location: https://github.com/datameet/Municipal_Spatial_Data/tree/master/Bhubaneswar

Having the original data, as compared to digitized data is better, because invariably some errors are introduced when you Georeference, and Digitize data, based off that.

Regards,

Devdatta

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[Pratyush Mohapatra]

How did you scrape off the data? 

Regards,

Devdatta

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[Devdatta Tengshe]

The way to do this, is to first figure out the Backend of the map. If you use Chrome's Developer tools, and look at the Network Tab, you can Find out where the data is coming from. I found out that it coming from an ArcGIS Server REST endpoint at http://bhubaneswarone.in/arcgis/rest/services/.

You will find a number of layers, and say that I want to get the data for the BMC boundry, which is available at: http://bhubaneswarone.in/arcgis/rest/services/Boundry/MapServer/

The Actual Boundry is at layer number 2, and then you can query it by using the following URL

http://bhubaneswarone.in/arcgis/rest/services/Boundry/MapServer/2/query?where=1%3D1&text=&objectIds=&time=&geometry=&geometryType=esriGeometryEnvelope&inSR=&spatialRel=esriSpatialRelIntersects&relationParam=&outFields=*&returnGeometry=true&returnTrueCurves=false&maxAllowableOffset=&geometryPrecision=&outSR=&returnIdsOnly=false&returnCountOnly=false&orderByFields=&groupByFieldsForStatistics=&outStatistics=&returnZ=false&returnM=false&gdbVersion=&returnDistinctValues=false&resultOffset=&resultRecordCount=&f=geojson

This gives you data in GeoJSON

Regards,

Devdatta

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[Nikhil VJ]

Great work, pratyuksh!

Devdatta, not simple at all, but wow, total Inside Man type ;)

Scraping off a google maps backend was how i'd gotten the pune maps too: first from an ngo's website (i did beg first!), and then more accurate data from a pune corporation's map that was there to show polling booths .

Right-click > inspect element > network > click only XHR, and then i refreshed the page.

The tracing guide is for cases where you have only raster (printed/jpg/pdf) maps, that too high-res. If we do come across vector data (ie, on a web map) then its possible to scrape.

Has anyone cracked how to extract vector data from a layered pdf map (exported from autocad etc)? couldnt find anything on the net for it; many others have posted facing the same challenge.

The development plan maps we have.. have multiple layers including census block boundaries. Converting to image, all the layers pile up and the output is very difficult to read, one layer censors the one below it. Even if i could just disable the other layers and convert to image, that would be great.

-nikhil