Re: [datameet] Re: Query about the 2011 Districts shapefile
Dear Devdatta,
OK. I wonder why I get 531/641 matches if the codes do not have the
SAME meaning in both (the map and the lgdirectory ) datasets.
What about ST_CEN_CD and DT_CEN_CD in the 2001 / 2011 Districts
shapefiles ? Are those BOTH the Census codes for States and Districts
respectively in 2001 ?
I wish someone wrote a README explaining the column names in 2001/2011
Districts and States shapefiles.
Best,
Ashim
On Wed, Dec 8, 2021 at 3:12 PM Devdatta Tengshe wrote:
>
> When this data was created, the Census Tables were not available, and it was
> created by digitising the maps given in the Administrative Atlas PDF
> available on the Census Website.
>
> So it included only the numbers available in the Administrative Atlas, and
> not the actual codes that are available in the CENSUS Tables.
>
> Source: I was part of the India-WRIS team which had created this data.
>
> Regards,
> Devdatta
>
>
> On Wed, 8 Dec 2021 at 14:49, Ashim Kapoor wrote:
>>
>> Dear Devdatta,
>>
>> Many thanks for your reply.
>>
>> The website:
>>
>> https://lgdirectory.gov.in
>>
>> has Census 2001, Census 2011 codes for ALL Districts of India.
>>
>> Example on this website:
>>
>> For the State of Maharashtra, the districts Ahmednagar, Akola and
>> Amrawati have Census 2011 codes = 522,501,503.
>>
>> In the 2011 shapefile the `censuscodes` for 522,501,503 correspond to
>> Districts Ahmadnagar, Akola Amrawati.
>>
>> I have done a "outer join" of District names by
>> censuscode=Census2011.Code and I get 531 / 641 matches.
>>
>> Please see the attached text file. I do not think this is happening by
>> "chance". I do think that the censuscodes column in the 2011 Districts
>> shapefile is the Census 2011 codes for Districts.
>>
>> Best,
>> Ashim
>>
>> On Wed, Dec 8, 2021 at 1:47 PM Devdatta Tengshe wrote:
>> >
>> > The 'censuscode' is just a sequential ID, going from 0 (for POK Areas) to
>> > 640.
>> >
>> > As far as I know, it has nothing to do with either the 2001 Census code or
>> > 2011 Census.
>> >
>> >
>> >
>> >
>> > Regards,
>> > Devdatta
>> >
>> >
>> > On Wed, 8 Dec 2021 at 12:35, Ashim Kapoor wrote:
>> >>
>> >> Dear All,
>> >>
>> >> I was a little confused.
>> >>
>> >> Attached are the extracts from 2001 / 2011 shapefiles as snippet.
>> >>
>> >> I think censuscode in 2011 shapefile = Census 2011 code for a District.
>> >> I further think DT_CEN_CD in 2011 OR 2011 shapefiles = Census 2001
>> >> code for a District.
>> >>
>> >> I would like to confirm this.
>> >>
>> >> Best,
>> >> Ashim
>> >>
>> >> 8<-snippet>8-
>> >>
>> >> > st_read("Census_2011/2011_Dist.shp") %>% filter(DISTRICT=="Ahmadnagar")
>> >> Reading layer `2011_Dist' from data source
>> >>
>> >> `/home/ashim/Documents/my-workspace/space-to-verify-state-census-codes-from-districts-shapefile/maps/Districts/Census_2011/2011_Dist.shp'
>> >> using driver `ESRI Shapefile'
>> >> Simple feature collection with 641 features and 5 fields
>> >> Geometry type: MULTIPOLYGON
>> >> Dimension: XY
>> >> Bounding box: xmin: 68.18625 ymin: 6.755953 xmax: 97.41529 ymax: 37.07827
>> >> CRS: 4326
>> >> Simple feature collection with 1 feature and 5 fields
>> >> Geometry type: MULTIPOLYGON
>> >> Dimension: XY
>> >> Bounding box: xmin: 73.62021 ymin: 18.33075 xmax: 75.58884 ymax: 19.98771
>> >> CRS: 4326
>> >> DISTRICT ST_NM ST_CEN_CD DT_CEN_CD censuscode
>> >> 1 Ahmadnagar Maharashtra2726522
>> >> geometry
>> >> 1 MULTIPOLYGON (((74.67333 19...
>> >> > st_read("Census_2001/2001_Dist.shp") %>% filter(DISTRICT=="Ahmadnagar")
>> >> Reading layer `2001_Dist' from data source
>> >>
>> >> `/home/ashim/Documents/my-workspace/space-to-verify-state-census-codes-from-districts-shapefile/maps/Districts/Census_2001/2001_Dist.shp'
>> >> using driver `ESRI Shapefile'
>> >> Simple feature collection with 594 features and 4 fields
>> >> Geometry type: MULTIPOLYGON
>> >> Dimension: XY
>> >> Bounding
Re: [datameet] Re: Query about the 2011 Districts shapefile
Dear Devdatta,
Many thanks for your reply.
The website:
https://lgdirectory.gov.in
has Census 2001, Census 2011 codes for ALL Districts of India.
Example on this website:
For the State of Maharashtra, the districts Ahmednagar, Akola and
Amrawati have Census 2011 codes = 522,501,503.
In the 2011 shapefile the `censuscodes` for 522,501,503 correspond to
Districts Ahmadnagar, Akola Amrawati.
I have done a "outer join" of District names by
censuscode=Census2011.Code and I get 531 / 641 matches.
Please see the attached text file. I do not think this is happening by
"chance". I do think that the censuscodes column in the 2011 Districts
shapefile is the Census 2011 codes for Districts.
Best,
Ashim
On Wed, Dec 8, 2021 at 1:47 PM Devdatta Tengshe wrote:
>
> The 'censuscode' is just a sequential ID, going from 0 (for POK Areas) to 640.
>
> As far as I know, it has nothing to do with either the 2001 Census code or
> 2011 Census.
>
>
>
>
> Regards,
> Devdatta
>
>
> On Wed, 8 Dec 2021 at 12:35, Ashim Kapoor wrote:
>>
>> Dear All,
>>
>> I was a little confused.
>>
>> Attached are the extracts from 2001 / 2011 shapefiles as snippet.
>>
>> I think censuscode in 2011 shapefile = Census 2011 code for a District.
>> I further think DT_CEN_CD in 2011 OR 2011 shapefiles = Census 2001
>> code for a District.
>>
>> I would like to confirm this.
>>
>> Best,
>> Ashim
>>
>> 8<-snippet>8-
>>
>> > st_read("Census_2011/2011_Dist.shp") %>% filter(DISTRICT=="Ahmadnagar")
>> Reading layer `2011_Dist' from data source
>>
>> `/home/ashim/Documents/my-workspace/space-to-verify-state-census-codes-from-districts-shapefile/maps/Districts/Census_2011/2011_Dist.shp'
>> using driver `ESRI Shapefile'
>> Simple feature collection with 641 features and 5 fields
>> Geometry type: MULTIPOLYGON
>> Dimension: XY
>> Bounding box: xmin: 68.18625 ymin: 6.755953 xmax: 97.41529 ymax: 37.07827
>> CRS: 4326
>> Simple feature collection with 1 feature and 5 fields
>> Geometry type: MULTIPOLYGON
>> Dimension: XY
>> Bounding box: xmin: 73.62021 ymin: 18.33075 xmax: 75.58884 ymax: 19.98771
>> CRS: 4326
>> DISTRICT ST_NM ST_CEN_CD DT_CEN_CD censuscode
>> 1 Ahmadnagar Maharashtra2726522
>> geometry
>> 1 MULTIPOLYGON (((74.67333 19...
>> > st_read("Census_2001/2001_Dist.shp") %>% filter(DISTRICT=="Ahmadnagar")
>> Reading layer `2001_Dist' from data source
>>
>> `/home/ashim/Documents/my-workspace/space-to-verify-state-census-codes-from-districts-shapefile/maps/Districts/Census_2001/2001_Dist.shp'
>> using driver `ESRI Shapefile'
>> Simple feature collection with 594 features and 4 fields
>> Geometry type: MULTIPOLYGON
>> Dimension: XY
>> Bounding box: xmin: 68.18625 ymin: 6.755953 xmax: 97.41529 ymax: 37.07827
>> CRS: 4326
>> Simple feature collection with 1 feature and 4 fields
>> Geometry type: MULTIPOLYGON
>> Dimension: XY
>> Bounding box: xmin: 73.62021 ymin: 18.33075 xmax: 75.58884 ymax: 19.98771
>> CRS: 4326
>> ST_NM ST_CEN_CD DT_CEN_CD DISTRICT geometry
>> 1 Maharashtra2726 Ahmadnagar MULTIPOLYGON (((74.67333 19...
>> >
>>
>> On Wed, Dec 8, 2021 at 11:18 AM Ashim Kapoor wrote:
>> >
>> > Deall All,
>> >
>> > I am working with the Districts shapefile using R.
>> >
>> > The file is located here:
>> >
>> > https://github.com/datameet/maps/tree/master/Districts
>> >
>> > Here are some records from this shapefile:
>> >
>> > > districts.map.with.crs %>% head
>> > Simple feature collection with 6 features and 5 fields
>> > Geometry type: MULTIPOLYGON
>> > Dimension: XY
>> > Bounding box: xmin: 71.60734 ymin: 18.33075 xmax: 93.20723 ymax: 27.40883
>> > CRS: EPSG:4326
>> > district st_nm st_cen_cd dt_cen_cd censuscode
>> > 1 Adilabad Andhra Pradesh28 1532
>> > 2 Agra Uttar Pradesh 915146
>> > 3 AhmadabadGujarat24 7474
>> > 4 AhmadnagarMaharashtra2726522
>> > 5 AizawlMizoram15 3283
>> > 6 Ajmer Rajasthan 821119
>> >SHAPE
>> > 1 MULT
[datameet] Re: Query about the 2011 Districts shapefile
Dear All,
I was a little confused.
Attached are the extracts from 2001 / 2011 shapefiles as snippet.
I think censuscode in 2011 shapefile = Census 2011 code for a District.
I further think DT_CEN_CD in 2011 OR 2011 shapefiles = Census 2001
code for a District.
I would like to confirm this.
Best,
Ashim
8<-snippet>8-
> st_read("Census_2011/2011_Dist.shp") %>% filter(DISTRICT=="Ahmadnagar")
Reading layer `2011_Dist' from data source
`/home/ashim/Documents/my-workspace/space-to-verify-state-census-codes-from-districts-shapefile/maps/Districts/Census_2011/2011_Dist.shp'
using driver `ESRI Shapefile'
Simple feature collection with 641 features and 5 fields
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: 68.18625 ymin: 6.755953 xmax: 97.41529 ymax: 37.07827
CRS: 4326
Simple feature collection with 1 feature and 5 fields
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: 73.62021 ymin: 18.33075 xmax: 75.58884 ymax: 19.98771
CRS: 4326
DISTRICT ST_NM ST_CEN_CD DT_CEN_CD censuscode
1 Ahmadnagar Maharashtra2726522
geometry
1 MULTIPOLYGON (((74.67333 19...
> st_read("Census_2001/2001_Dist.shp") %>% filter(DISTRICT=="Ahmadnagar")
Reading layer `2001_Dist' from data source
`/home/ashim/Documents/my-workspace/space-to-verify-state-census-codes-from-districts-shapefile/maps/Districts/Census_2001/2001_Dist.shp'
using driver `ESRI Shapefile'
Simple feature collection with 594 features and 4 fields
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: 68.18625 ymin: 6.755953 xmax: 97.41529 ymax: 37.07827
CRS: 4326
Simple feature collection with 1 feature and 4 fields
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: 73.62021 ymin: 18.33075 xmax: 75.58884 ymax: 19.98771
CRS: 4326
ST_NM ST_CEN_CD DT_CEN_CD DISTRICT geometry
1 Maharashtra2726 Ahmadnagar MULTIPOLYGON (((74.67333 19...
>
On Wed, Dec 8, 2021 at 11:18 AM Ashim Kapoor wrote:
>
> Deall All,
>
> I am working with the Districts shapefile using R.
>
> The file is located here:
>
> https://github.com/datameet/maps/tree/master/Districts
>
> Here are some records from this shapefile:
>
> > districts.map.with.crs %>% head
> Simple feature collection with 6 features and 5 fields
> Geometry type: MULTIPOLYGON
> Dimension: XY
> Bounding box: xmin: 71.60734 ymin: 18.33075 xmax: 93.20723 ymax: 27.40883
> CRS: EPSG:4326
> district st_nm st_cen_cd dt_cen_cd censuscode
> 1 Adilabad Andhra Pradesh28 1532
> 2 Agra Uttar Pradesh 915146
> 3 AhmadabadGujarat24 7474
> 4 AhmadnagarMaharashtra2726522
> 5 AizawlMizoram15 3283
> 6 Ajmer Rajasthan 821119
>SHAPE
> 1 MULTIPOLYGON (((78.84972 19...
> 2 MULTIPOLYGON (((78.19803 27...
> 3 MULTIPOLYGON (((72.03456 23...
> 4 MULTIPOLYGON (((74.67333 19...
> 5 MULTIPOLYGON (((92.98749 24...
> 6 MULTIPOLYGON (((74.89253 26...
> >
>
> I have a question:
>
> In the Districts shapefile:
>
> st_cen_cd is the 2011 census code for States.
> dt_cen_cd is the 2011 census code for Districts.
> censuscode is the 2001 census code for Districts.
>
> Is the above correct? Especially the censuscode. Is it the 2001 census
> code for a District? Is this mentioned somewhere ?
>
> Many thanks,
> Ashim
--
Datameet is a community of Data Science enthusiasts in India. Know more about
us by visiting http://datameet.org
---
You received this message because you are subscribed to the Google Groups
"datameet" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to datameet+unsubscr...@googlegroups.com.
To view this discussion on the web visit
https://groups.google.com/d/msgid/datameet/CAC8%3D1eoNrTUkrKUWNUO67904wqR4qo1kzEYk319ZYQ2%2Bkez3nQ%40mail.gmail.com.
[datameet] Query about the 2011 Districts shapefile
Deall All, I am working with the Districts shapefile using R. The file is located here: https://github.com/datameet/maps/tree/master/Districts Here are some records from this shapefile: > districts.map.with.crs %>% head Simple feature collection with 6 features and 5 fields Geometry type: MULTIPOLYGON Dimension: XY Bounding box: xmin: 71.60734 ymin: 18.33075 xmax: 93.20723 ymax: 27.40883 CRS: EPSG:4326 district st_nm st_cen_cd dt_cen_cd censuscode 1 Adilabad Andhra Pradesh28 1532 2 Agra Uttar Pradesh 915146 3 AhmadabadGujarat24 7474 4 AhmadnagarMaharashtra2726522 5 AizawlMizoram15 3283 6 Ajmer Rajasthan 821119 SHAPE 1 MULTIPOLYGON (((78.84972 19... 2 MULTIPOLYGON (((78.19803 27... 3 MULTIPOLYGON (((72.03456 23... 4 MULTIPOLYGON (((74.67333 19... 5 MULTIPOLYGON (((92.98749 24... 6 MULTIPOLYGON (((74.89253 26... > I have a question: In the Districts shapefile: st_cen_cd is the 2011 census code for States. dt_cen_cd is the 2011 census code for Districts. censuscode is the 2001 census code for Districts. Is the above correct? Especially the censuscode. Is it the 2001 census code for a District? Is this mentioned somewhere ? Many thanks, Ashim -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/datameet/CAC8%3D1er_Jq3dopkiEyGF4EiknHHC260dphpo2eG6d-iBrex0Jw%40mail.gmail.com.
Re: [datameet] Re: Correct CRS for datameet maps
Dear Sharad, My apologies for the delay in responding.(The week was blissfully busy and I lost track of responding to this email). My response is inline. On Thu, Apr 18, 2019 at 11:09 PM Sharad Lele wrote: > Devdatta's summary was short and sweet, and practical. To add to it: > > 1. The NNRMS CRS suggested seems to be in Lambert Conformal Conic > projection (with WGS84 ellipsoid and datum). An alternative to it is the > UTM projection system, which keeps longitudes parallel, and gives > reasonably accurate area estimate. The particular UTM zone one may use > varies by which part of India one is in. > 2. In common parlance, 'unprojected' means having no Coordinate Reference > System at all. In GIS parlance, 'unprojected' may be understood as > 'geographic' CRS, that is, in lat-long rather than in metres. I presume > Ashim means 'having no CRS' at all. Whether one's map needs a CRS or not > depends upon what use one wants to put it to (and hence how accurate it > must be) and its size. A map of a 60'x40' piece of land does not require a > CRS if the purpose is house construction. It may require a CRS if one is > setting up a telescope on it which will do interferometry with another > telescope 500km away. A map of even a layout or a village or small town may > not need a CRS if one wants approximate locations/directions to navigate > visually (old style). It will need a CRS if one wants to use a GPS to > navigate. > If, Ashim, you mean 'geographic' vs 'projected' system, the answer is > different: geographic is useful for representation, easy to understand > (lat-long concept), but not to be used for calculating distances and areas. > I think when the data is "unprojected", it simply plots the points in a plane based on the co-ordinates( long / lat) . When it is projected it uses a transformation to go from points ( long / lat ) -> 2D map. > Hope this helps. Devdatta and others: please correct/supplement. > Sharad > > On Tuesday, April 16, 2019 at 3:38:08 PM UTC+5:30, Ashim wrote: >> >> Dear All, >> >> I have a small query on similar lines. When do we use UNPROJECTED maps ? >> I understand that to go from 3D to 2D we need a projection. When is it >> reasonable to use an unprojected map? >> >> Many thanks, >> Ashim >> >> On Tue, Apr 16, 2019 at 12:12 PM Ashim Kapoor wrote: >> >>> Dear Devdatta and Nikhil, >>> >>> I attended a R GIS school where the teachers were from France and they >>> were using CRS 2154. They told us that they were not familiar with the CRS >>> for Indian maps. >>> >>> I used 2154 thinking that it would not make much of a difference, but I >>> was wrong. My apologies for the confusion. When I used that on Indian ( >>> datameet ) shapefiles,I got this : map1.png ( see attachment ) >>> >>> I have also attached the R code to create these maps from the Datameet >>> District level ( 2011 ) shapefiles. I have created map2.png and map3.png >>> from crs = 3857 / 7755 respectively. >>> >>> I also found this : >>> https://epsg.io/?q=india >>> >>> Which is confusing because many CRS are there for India. Why do we have >>> so many choices of CRS for India ? >>> >>> I guess for the time being I will use 7755. >>> >>> Many thanks to Devdatta and Nikhil for their help. >>> Best Regards, >>> Ashim >>> >>> >>> >>> On Tue, Apr 16, 2019 at 11:42 AM Nikhil VJ wrote: >>> >>>> Hi Ashim, >>>> >>>> Pls provide the exact link of what you're referring - this stuff is >>>> never as much on the top of people's minds as we assume it to be. >>>> Do try loading your shapefiles on other tools and check there : >>>> mapshaper.org is a site that does a lot of quick, cool things with >>>> shapefiles; QGIS is a software that does everything with shapefiles. Both >>>> are free and open source. >>>> >>>> The latter will help you re-save the shapefile into any CRS you want. >>>> Right-click the layer > Save As (or "Export") and remember to choose your >>>> preferred CRS in the dropdown. >>>> >>>> Can you give background on what this CRS : *2154* : is and why you >>>> want to transform to that? Because I've only come across two main CRS's >>>> both being under the "WSG 84" category : >>>> - EPSG 4326 : this makes everything in latitude longitude >>>> - EPSG 3857 : this makes everything in meters from the equator (I >>>> think) and we ne
Re: [datameet] Re: Correct CRS for datameet maps
Dear All,
I have a small query on similar lines. When do we use UNPROJECTED maps ? I
understand that to go from 3D to 2D we need a projection. When is it
reasonable to use an unprojected map?
Many thanks,
Ashim
On Tue, Apr 16, 2019 at 12:12 PM Ashim Kapoor wrote:
> Dear Devdatta and Nikhil,
>
> I attended a R GIS school where the teachers were from France and they
> were using CRS 2154. They told us that they were not familiar with the CRS
> for Indian maps.
>
> I used 2154 thinking that it would not make much of a difference, but I
> was wrong. My apologies for the confusion. When I used that on Indian (
> datameet ) shapefiles,I got this : map1.png ( see attachment )
>
> I have also attached the R code to create these maps from the Datameet
> District level ( 2011 ) shapefiles. I have created map2.png and map3.png
> from crs = 3857 / 7755 respectively.
>
> I also found this :
> https://epsg.io/?q=india
>
> Which is confusing because many CRS are there for India. Why do we have so
> many choices of CRS for India ?
>
> I guess for the time being I will use 7755.
>
> Many thanks to Devdatta and Nikhil for their help.
> Best Regards,
> Ashim
>
>
>
> On Tue, Apr 16, 2019 at 11:42 AM Nikhil VJ wrote:
>
>> Hi Ashim,
>>
>> Pls provide the exact link of what you're referring - this stuff is never
>> as much on the top of people's minds as we assume it to be.
>> Do try loading your shapefiles on other tools and check there :
>> mapshaper.org is a site that does a lot of quick, cool things with
>> shapefiles; QGIS is a software that does everything with shapefiles. Both
>> are free and open source.
>>
>> The latter will help you re-save the shapefile into any CRS you want.
>> Right-click the layer > Save As (or "Export") and remember to choose your
>> preferred CRS in the dropdown.
>>
>> Can you give background on what this CRS : *2154* : is and why you want
>> to transform to that? Because I've only come across two main CRS's both
>> being under the "WSG 84" category :
>> - EPSG 4326 : this makes everything in latitude longitude
>> - EPSG 3857 : this makes everything in meters from the equator (I think)
>> and we need to get the data in this format when we want to do things in
>> physical distance terms like making a 1km distance buffer or measuring areas
>>
>> I haven't learned GIS stuff from theory, I just use it, so don't know
>> more details about CRS. I do understand that the dizzying multitude of
>> CRS's out there are so because apparently GIS folks like to re-orient the
>> center of the world (geometrically speaking) to where their data is to
>> ensure least distortion of their shapes in the rendering. When I come
>> across anything that's in a non-standard CRS, my first move is to transform
>> it to either lat-longs (4326) or meters (3857).
>>
>> Regards
>> Nikhil VJ
>>
>>
>> On Monday, April 15, 2019 at 1:57:20 PM UTC+5:30, Ashim wrote:
>>>
>>> Dear All,
>>>
>>> I am referring to 2011_Dist. * set of shapefile. (District level
>>> shapefiles).
>>>
>>> When I read them as simple features in R, ( like this )
>>>
>>> map <- st_read("2011_Dist.shp") %>% st_as_sf()
>>>
>>> ( it's unprojected because it says 4326 in the epsg when I read the
>>> above )
>>>
>>> plot(map$geometry)
>>>
>>> it looks OK.
>>>
>>> But when I do :
>>>
>>> map <- st_read("2011_Dist.shp") %>% st_as_sf() %>% st_transform(crs=
>>> 2154)
>>>
>>> plot(map$geometry)
>>>
>>> the map is TILTED.
>>>
>>> What is the correct projection to use for this dataset? Please clarify.
>>>
>>> Best Regards,
>>> Ashim
>>>
>> --
>> Datameet is a community of Data Science enthusiasts in India. Know more
>> about us by visiting http://datameet.org
>> ---
>> You received this message because you are subscribed to the Google Groups
>> "datameet" group.
>> To unsubscribe from this group and stop receiving emails from it, send an
>> email to datameet+unsubscr...@googlegroups.com.
>> For more options, visit https://groups.google.com/d/optout.
>>
>
--
Datameet is a community of Data Science enthusiasts in India. Know more about
us by visiting http://datameet.org
---
You received this message because you are subscribed to the Google Groups
"datameet" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to datameet+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
Re: [datameet] Re: Correct CRS for datameet maps
Dear Devdatta and Nikhil,
I attended a R GIS school where the teachers were from France and they were
using CRS 2154. They told us that they were not familiar with the CRS for
Indian maps.
I used 2154 thinking that it would not make much of a difference, but I
was wrong. My apologies for the confusion. When I used that on Indian (
datameet ) shapefiles,I got this : map1.png ( see attachment )
I have also attached the R code to create these maps from the Datameet
District level ( 2011 ) shapefiles. I have created map2.png and map3.png
from crs = 3857 / 7755 respectively.
I also found this :
https://epsg.io/?q=india
Which is confusing because many CRS are there for India. Why do we have so
many choices of CRS for India ?
I guess for the time being I will use 7755.
Many thanks to Devdatta and Nikhil for their help.
Best Regards,
Ashim
On Tue, Apr 16, 2019 at 11:42 AM Nikhil VJ wrote:
> Hi Ashim,
>
> Pls provide the exact link of what you're referring - this stuff is never
> as much on the top of people's minds as we assume it to be.
> Do try loading your shapefiles on other tools and check there :
> mapshaper.org is a site that does a lot of quick, cool things with
> shapefiles; QGIS is a software that does everything with shapefiles. Both
> are free and open source.
>
> The latter will help you re-save the shapefile into any CRS you want.
> Right-click the layer > Save As (or "Export") and remember to choose your
> preferred CRS in the dropdown.
>
> Can you give background on what this CRS : *2154* : is and why you want
> to transform to that? Because I've only come across two main CRS's both
> being under the "WSG 84" category :
> - EPSG 4326 : this makes everything in latitude longitude
> - EPSG 3857 : this makes everything in meters from the equator (I think)
> and we need to get the data in this format when we want to do things in
> physical distance terms like making a 1km distance buffer or measuring areas
>
> I haven't learned GIS stuff from theory, I just use it, so don't know more
> details about CRS. I do understand that the dizzying multitude of CRS's out
> there are so because apparently GIS folks like to re-orient the center of
> the world (geometrically speaking) to where their data is to ensure least
> distortion of their shapes in the rendering. When I come across anything
> that's in a non-standard CRS, my first move is to transform it to either
> lat-longs (4326) or meters (3857).
>
> Regards
> Nikhil VJ
>
>
> On Monday, April 15, 2019 at 1:57:20 PM UTC+5:30, Ashim wrote:
>>
>> Dear All,
>>
>> I am referring to 2011_Dist. * set of shapefile. (District level
>> shapefiles).
>>
>> When I read them as simple features in R, ( like this )
>>
>> map <- st_read("2011_Dist.shp") %>% st_as_sf()
>>
>> ( it's unprojected because it says 4326 in the epsg when I read the above
>> )
>>
>> plot(map$geometry)
>>
>> it looks OK.
>>
>> But when I do :
>>
>> map <- st_read("2011_Dist.shp") %>% st_as_sf() %>% st_transform(crs= 2154)
>>
>> plot(map$geometry)
>>
>> the map is TILTED.
>>
>> What is the correct projection to use for this dataset? Please clarify.
>>
>> Best Regards,
>> Ashim
>>
> --
> Datameet is a community of Data Science enthusiasts in India. Know more
> about us by visiting http://datameet.org
> ---
> You received this message because you are subscribed to the Google Groups
> "datameet" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to datameet+unsubscr...@googlegroups.com.
> For more options, visit https://groups.google.com/d/optout.
>
--
Datameet is a community of Data Science enthusiasts in India. Know more about
us by visiting http://datameet.org
---
You received this message because you are subscribed to the Google Groups
"datameet" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to datameet+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
map.R
Description: Binary data
[datameet] Correct CRS for datameet maps
Dear All,
I am referring to 2011_Dist. * set of shapefile. (District level
shapefiles).
When I read them as simple features in R, ( like this )
map <- st_read("2011_Dist.shp") %>% st_as_sf()
( it's unprojected because it says 4326 in the epsg when I read the above )
plot(map$geometry)
it looks OK.
But when I do :
map <- st_read("2011_Dist.shp") %>% st_as_sf() %>% st_transform(crs= 2154)
plot(map$geometry)
the map is TILTED.
What is the correct projection to use for this dataset? Please clarify.
Best Regards,
Ashim
--
Datameet is a community of Data Science enthusiasts in India. Know more about
us by visiting http://datameet.org
---
You received this message because you are subscribed to the Google Groups
"datameet" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to datameet+unsubscr...@googlegroups.com.
For more options, visit https://groups.google.com/d/optout.
Re: [datameet] Rural vs urban areas in India
Dear Arun, Many thanks for your prompt reply. One person here says it's commercially available from GIS vendors:- https://www.quora.com/Maps-Where-we-can-find-the-list-of-all-villages-of-India-with-their-longitude-and-latitude I will explore the data set that you have suggested. Best Regards, Ashim On Wed, Jan 16, 2019 at 5:59 PM Arun Ganesh wrote: > You got lucky, i just happened to be looking for this an hour ago. > > You can use the data from Global Human Settlement dataset Settlement Grid: > https://ghsl.jrc.ec.europa.eu/datasets.php > > Its a gridded raster tif where each pixel has a value for urbanization. If > you load it into qgis and use some python, you can classify an input set of > points if they are urban or rural. > > Dont know if theres a ready API already available that already offers this > as a service. > > -- > Datameet is a community of Data Science enthusiasts in India. Know more > about us by visiting http://datameet.org > --- > You received this message because you are subscribed to the Google Groups > "datameet" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to datameet+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[datameet] Rural vs urban areas in India
Dear all, Is there any way that given a lat long in India, we can classify it as rural / urban ? Best Regards, Ashim -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [datameet] States shapefile is based on which Census Year ?
Dear Devdatta. This page : http://projects.datameet.org/maps/districts/ says : The District Boundaries of India, Scraped from ECI's Poling Station Locations <http://psleci.nic.in/> Website. Wouldn’t the ECI website have the latest data on Districts? Since the Districts boundaries are scraped from ECI's website wouldn’t we have the latest Districts boundaries ? Where do I misunderstand ? Best Regards, Ashim On Fri, Apr 27, 2018 at 12:25 PM, Devdatta Tengshe <devda...@tengshe.in> wrote: > > we are approximately correct is using both the State and the District > shapefiles ? > > No! > The states represent the current boundaries, while the districts shapefile > represent the 2001 Census & 2011 Census. > > We do not have a District file for the Current boundaries & names. > > Regards, > Devdatta > > On Fri, Apr 27, 2018 at 12:22 PM, Ashim Kapoor <ashimkap...@gmail.com> > wrote: > >> Dear Devdatta, >> >> Thank you once again for the prompt reply. So if I understand correctly, >> we are approximately correct is using both the State and the District >> shapefiles ? >> >> Warm Regards, >> Ashim >> >> On Fri, Apr 27, 2018 at 12:13 PM, Devdatta Tengshe <devda...@tengshe.in> >> wrote: >> >>> Hi Ashim, >>> >>> Both those sections are incorrect. I've created a >>> https://github.com/datameet/maps/issues/28 for the same. >>> >>> The States folder at https://github.com/datameet/maps/ contains updated >>> State Boundries, while the District have information from 2011 & 2001 >>> Census. >>> >>> Regards, >>> Devdatta >>> >>> On Fri, Apr 27, 2018 at 11:53 AM, Ashim Kapoor <ashimkap...@gmail.com> >>> wrote: >>> >>>> Dear Devdatta, >>>> >>>> Many thanks for your reply. >>>> >>>> On this page: >>>> >>>> http://projects.datameet.org/maps/states/ >>>> >>>> Item 3 says : >>>> >>>> Some State Boundaries Names seem to be incorrect or Missing. >>>> >>>> Also on this page : >>>> >>>> http://projects.datameet.org/maps/districts/ >>>> >>>> Item 3 says : >>>> Some Assemblies Constituency Names seem to be incorrect or Missing. >>>> >>>> Can you please clarify which ones are these ? Is there a list of >>>> Incorrect/Missing States / Districts ? >>>> >>>> Best Regards, >>>> Ashim >>>> >>>> On Fri, Apr 27, 2018 at 11:31 AM, Devdatta Tengshe <devda...@tengshe.in >>>> > wrote: >>>> >>>>> This data was originally based on the 2011 Census; We have then >>>>> partitioned AP and also updated the Telangan Boundary based on the 2015 >>>>> Order. >>>>> >>>>> So this data approximately represents the current situation. >>>>> >>>>> Regards, >>>>> Devdatta >>>>> >>>>> On Fri, Apr 27, 2018 at 9:57 AM, Ashim Kapoor <ashimkap...@gmail.com> >>>>> wrote: >>>>> >>>>>> Dear all, >>>>>> >>>>>> I am referring to the State maps here : >>>>>> >>>>>> http://projects.datameet.org/maps/states/ >>>>>> >>>>>> My query is : what Census year is this based on ? Can someone clarify >>>>>> ? >>>>>> >>>>>> Best Regards, >>>>>> Ashim >>>>>> >>>>>> -- >>>>>> Datameet is a community of Data Science enthusiasts in India. Know >>>>>> more about us by visiting http://datameet.org >>>>>> --- >>>>>> You received this message because you are subscribed to the Google >>>>>> Groups "datameet" group. >>>>>> To unsubscribe from this group and stop receiving emails from it, >>>>>> send an email to datameet+unsubscr...@googlegroups.com. >>>>>> For more options, visit https://groups.google.com/d/optout. >>>>>> >>>>> >>>>> -- >>>>> Datameet is a community of Data Science enthusiasts in India. Know >>>>> more about us by visiting http://datameet.org >>>>> --- >>>>> You received this message because you are subscribed to the Google >>>>> Groups "datameet" group. &g
Re: [datameet] States shapefile is based on which Census Year ?
Dear Devdatta, Thank you once again for the prompt reply. So if I understand correctly, we are approximately correct is using both the State and the District shapefiles ? Warm Regards, Ashim On Fri, Apr 27, 2018 at 12:13 PM, Devdatta Tengshe <devda...@tengshe.in> wrote: > Hi Ashim, > > Both those sections are incorrect. I've created a > https://github.com/datameet/maps/issues/28 for the same. > > The States folder at https://github.com/datameet/maps/ contains updated > State Boundries, while the District have information from 2011 & 2001 > Census. > > Regards, > Devdatta > > On Fri, Apr 27, 2018 at 11:53 AM, Ashim Kapoor <ashimkap...@gmail.com> > wrote: > >> Dear Devdatta, >> >> Many thanks for your reply. >> >> On this page: >> >> http://projects.datameet.org/maps/states/ >> >> Item 3 says : >> >> Some State Boundaries Names seem to be incorrect or Missing. >> >> Also on this page : >> >> http://projects.datameet.org/maps/districts/ >> >> Item 3 says : >> Some Assemblies Constituency Names seem to be incorrect or Missing. >> >> Can you please clarify which ones are these ? Is there a list of >> Incorrect/Missing States / Districts ? >> >> Best Regards, >> Ashim >> >> On Fri, Apr 27, 2018 at 11:31 AM, Devdatta Tengshe <devda...@tengshe.in> >> wrote: >> >>> This data was originally based on the 2011 Census; We have then >>> partitioned AP and also updated the Telangan Boundary based on the 2015 >>> Order. >>> >>> So this data approximately represents the current situation. >>> >>> Regards, >>> Devdatta >>> >>> On Fri, Apr 27, 2018 at 9:57 AM, Ashim Kapoor <ashimkap...@gmail.com> >>> wrote: >>> >>>> Dear all, >>>> >>>> I am referring to the State maps here : >>>> >>>> http://projects.datameet.org/maps/states/ >>>> >>>> My query is : what Census year is this based on ? Can someone clarify ? >>>> >>>> Best Regards, >>>> Ashim >>>> >>>> -- >>>> Datameet is a community of Data Science enthusiasts in India. Know more >>>> about us by visiting http://datameet.org >>>> --- >>>> You received this message because you are subscribed to the Google >>>> Groups "datameet" group. >>>> To unsubscribe from this group and stop receiving emails from it, send >>>> an email to datameet+unsubscr...@googlegroups.com. >>>> For more options, visit https://groups.google.com/d/optout. >>>> >>> >>> -- >>> Datameet is a community of Data Science enthusiasts in India. Know more >>> about us by visiting http://datameet.org >>> --- >>> You received this message because you are subscribed to the Google >>> Groups "datameet" group. >>> To unsubscribe from this group and stop receiving emails from it, send >>> an email to datameet+unsubscr...@googlegroups.com. >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> -- >> Datameet is a community of Data Science enthusiasts in India. Know more >> about us by visiting http://datameet.org >> --- >> You received this message because you are subscribed to the Google Groups >> "datameet" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to datameet+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > Datameet is a community of Data Science enthusiasts in India. Know more > about us by visiting http://datameet.org > --- > You received this message because you are subscribed to the Google Groups > "datameet" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to datameet+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [datameet] States shapefile is based on which Census Year ?
Dear Devdatta, Many thanks for your reply. On this page: http://projects.datameet.org/maps/states/ Item 3 says : Some State Boundaries Names seem to be incorrect or Missing. Also on this page : http://projects.datameet.org/maps/districts/ Item 3 says : Some Assemblies Constituency Names seem to be incorrect or Missing. Can you please clarify which ones are these ? Is there a list of Incorrect/Missing States / Districts ? Best Regards, Ashim On Fri, Apr 27, 2018 at 11:31 AM, Devdatta Tengshe <devda...@tengshe.in> wrote: > This data was originally based on the 2011 Census; We have then > partitioned AP and also updated the Telangan Boundary based on the 2015 > Order. > > So this data approximately represents the current situation. > > Regards, > Devdatta > > On Fri, Apr 27, 2018 at 9:57 AM, Ashim Kapoor <ashimkap...@gmail.com> > wrote: > >> Dear all, >> >> I am referring to the State maps here : >> >> http://projects.datameet.org/maps/states/ >> >> My query is : what Census year is this based on ? Can someone clarify ? >> >> Best Regards, >> Ashim >> >> -- >> Datameet is a community of Data Science enthusiasts in India. Know more >> about us by visiting http://datameet.org >> --- >> You received this message because you are subscribed to the Google Groups >> "datameet" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to datameet+unsubscr...@googlegroups.com. >> For more options, visit https://groups.google.com/d/optout. >> > > -- > Datameet is a community of Data Science enthusiasts in India. Know more > about us by visiting http://datameet.org > --- > You received this message because you are subscribed to the Google Groups > "datameet" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to datameet+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[datameet] States shapefile is based on which Census Year ?
Dear all, I am referring to the State maps here : http://projects.datameet.org/maps/states/ My query is : what Census year is this based on ? Can someone clarify ? Best Regards, Ashim -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[datameet] 2011 Districts Shapefile seems to have an island inside Odisha
Dear All, I downloaded the shapefiles from : http://projects.datameet.org/maps/districts/ Then I subset it and kept only districts in Odisha and then took a union of all polygons in Odisha. When I did this I was expecting the boundary of Odisha. What I can see instead is the boundary of Odisha with a polygon inside it. Please see the attached code in R and the pdf generated by this code. I guess I can use the State shapefile for the state boundary of Odisha but I thought I would report this. Best Regards, Ashim -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout. code.R Description: Binary data map.pdf Description: Adobe PDF document
[datameet] Creating a Indian law approved map of India using OSM
Dear All, I need to create a shapefile of India using OSM data which shows the Indian version of the borders according to the existing law. Can someone point me in the right direction ? Many thanks, Ashim -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
Re: [datameet] are these shapefiles based on OSM ?
Dear Arun, Thank you. Best Regards, Ashim On Thu, Nov 2, 2017 at 3:34 PM, Arun Ganesh <arungra...@gmail.com> wrote: > > > On Thu, Nov 2, 2017 at 8:06 AM, Ashim Kapoor <ashimkap...@gmail.com> > wrote: > >> Dear All, >> >> I am looking for OSM based shapefile of India at the state and district >> level. Can someone point me in the right direction? >> > > > You can generate a shapefile for any arbitrary area using > https://mapzen.com/data/metro-extracts/ > > If you want one for each district, your best bet is to do it > programmatically with postgres and QGIS. > > > -- > Datameet is a community of Data Science enthusiasts in India. Know more > about us by visiting http://datameet.org > --- > You received this message because you are subscribed to the Google Groups > "datameet" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to datameet+unsubscr...@googlegroups.com. > For more options, visit https://groups.google.com/d/optout. > -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
[datameet] are these shapefiles based on OSM ?
Dear All, I have a query. Are the following shapefiles : http://datameet.org/indian-shapefiles-central/ based on open street map ? Please clarify. Best Regards, Ashim -- Datameet is a community of Data Science enthusiasts in India. Know more about us by visiting http://datameet.org --- You received this message because you are subscribed to the Google Groups "datameet" group. To unsubscribe from this group and stop receiving emails from it, send an email to datameet+unsubscr...@googlegroups.com. For more options, visit https://groups.google.com/d/optout.
