Map material from china not allowed to leave the country





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I just read an article about a company in germany which tests autonomous driving cars in different countries.

They state that they analyze all of the generated data in germany - with one exception: China.



"Because of legal regulations, no map material is allowed to leave the country."
Googling a few seconds for maps of china shows several results.



Can anyone explain this discrepancy?










share|improve this question







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TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
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  • 1





    youtube.com/watch?v=L9Di-UVC-_4

    – Michael Hampton
    8 hours ago


















9















I just read an article about a company in germany which tests autonomous driving cars in different countries.

They state that they analyze all of the generated data in germany - with one exception: China.



"Because of legal regulations, no map material is allowed to leave the country."
Googling a few seconds for maps of china shows several results.



Can anyone explain this discrepancy?










share|improve this question







New contributor




TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
















  • 1





    youtube.com/watch?v=L9Di-UVC-_4

    – Michael Hampton
    8 hours ago














9












9








9


1






I just read an article about a company in germany which tests autonomous driving cars in different countries.

They state that they analyze all of the generated data in germany - with one exception: China.



"Because of legal regulations, no map material is allowed to leave the country."
Googling a few seconds for maps of china shows several results.



Can anyone explain this discrepancy?










share|improve this question







New contributor




TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.












I just read an article about a company in germany which tests autonomous driving cars in different countries.

They state that they analyze all of the generated data in germany - with one exception: China.



"Because of legal regulations, no map material is allowed to leave the country."
Googling a few seconds for maps of china shows several results.



Can anyone explain this discrepancy?







legal china






share|improve this question







New contributor




TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|improve this question







New contributor




TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|improve this question




share|improve this question






New contributor




TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked 9 hours ago









TimSchTimSch

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New contributor




TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






TimSch is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 1





    youtube.com/watch?v=L9Di-UVC-_4

    – Michael Hampton
    8 hours ago














  • 1





    youtube.com/watch?v=L9Di-UVC-_4

    – Michael Hampton
    8 hours ago








1




1





youtube.com/watch?v=L9Di-UVC-_4

– Michael Hampton
8 hours ago





youtube.com/watch?v=L9Di-UVC-_4

– Michael Hampton
8 hours ago










2 Answers
2






active

oldest

votes


















12














I am not sure if the context of your question is really on-topic here, but since the answer and its implications is very much relevant for travellers as well, I'll give it a try.



The explanation you have read is not entirely accurate. The problem is that accurate map material is neither allowed to be published, nor to leave the country. The Chinese National Bureau of Surveying and Mapping require all companies to obtain permits for map surveying and published map data must be obfuscated, resulting in a deviation of up to 700m between the map and the real world. To quote a well-known German children tv show: Sounds strange, but that is how it is.



You can easily see the result of this obfuscation if you e.g. in Google Maps look at the satellite imagery with a map overlay. It is especially obvious in border proximity, where you will see that the map data for China is skewed, while the map outside China is correct. If you look at this area, the Shenzhen Bay with the border between China and Hong Kong, you can see that the map over Hong Kong in the lower right area is correct, while in the middle of the bay, the map seem to indicate that the bridge makes a sharp bend to the right, while you on the satellite image can see that the bridge in reality is straight. In the upper left area (mainland China), you can then see that there is a significant discrepancy between the imagery and the map. Roads seem to float on the water, pass through buildings and what else not.






share|improve this answer





















  • 5





    @TimSch The Chinese Surveying and Mapping Law does not explain why the restriction is in place. It is commonly quoted that it is for national security purposes, but I am not really sure if there is any official statement on that subject at all. Similar regulations and restrictions are actually quite common in many other countries as well, but usually do not apply to the entire country, just to 'places of interest'.

    – Tor-Einar Jarnbjo
    9 hours ago








  • 1





    Does china mandate how exactly the skewing will be done? Do they do it themselves or is it the companies' responsibility? Can I get a bunch of maps of china and take an average?

    – OganM
    6 hours ago






  • 4





    @OganM The obfuscation algorithm is prespecified, not publicly known, but obviously deterministic. Since a lot of example data is available, there have been attempts to reverse-engineer the algorithm and there are relatively reliable software libraries available allowing a backwards mapping from obfuscated to real coordinates. You can find more information and links to further resources on Wikipedia: en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China

    – Tor-Einar Jarnbjo
    6 hours ago






  • 2





    I work for a GIS software company and we looked at some of the online libraries. They were okay for a local area--usually Beijing, not usable for the entire country.

    – mkennedy
    5 hours ago






  • 2





    I opened up a question about the reasoning for this policy on Politics.SE: politics.stackexchange.com/questions/40991/…

    – indigochild
    4 hours ago



















4














China has some pretty strict laws (for national security purposes, it seems) related to mapping and geographical surveying, effectively outlawing it for non-nationals.



See OpenStreetMap's view of the topic.






share|improve this answer
























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    2 Answers
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    active

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    2 Answers
    2






    active

    oldest

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    active

    oldest

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    active

    oldest

    votes









    12














    I am not sure if the context of your question is really on-topic here, but since the answer and its implications is very much relevant for travellers as well, I'll give it a try.



    The explanation you have read is not entirely accurate. The problem is that accurate map material is neither allowed to be published, nor to leave the country. The Chinese National Bureau of Surveying and Mapping require all companies to obtain permits for map surveying and published map data must be obfuscated, resulting in a deviation of up to 700m between the map and the real world. To quote a well-known German children tv show: Sounds strange, but that is how it is.



    You can easily see the result of this obfuscation if you e.g. in Google Maps look at the satellite imagery with a map overlay. It is especially obvious in border proximity, where you will see that the map data for China is skewed, while the map outside China is correct. If you look at this area, the Shenzhen Bay with the border between China and Hong Kong, you can see that the map over Hong Kong in the lower right area is correct, while in the middle of the bay, the map seem to indicate that the bridge makes a sharp bend to the right, while you on the satellite image can see that the bridge in reality is straight. In the upper left area (mainland China), you can then see that there is a significant discrepancy between the imagery and the map. Roads seem to float on the water, pass through buildings and what else not.






    share|improve this answer





















    • 5





      @TimSch The Chinese Surveying and Mapping Law does not explain why the restriction is in place. It is commonly quoted that it is for national security purposes, but I am not really sure if there is any official statement on that subject at all. Similar regulations and restrictions are actually quite common in many other countries as well, but usually do not apply to the entire country, just to 'places of interest'.

      – Tor-Einar Jarnbjo
      9 hours ago








    • 1





      Does china mandate how exactly the skewing will be done? Do they do it themselves or is it the companies' responsibility? Can I get a bunch of maps of china and take an average?

      – OganM
      6 hours ago






    • 4





      @OganM The obfuscation algorithm is prespecified, not publicly known, but obviously deterministic. Since a lot of example data is available, there have been attempts to reverse-engineer the algorithm and there are relatively reliable software libraries available allowing a backwards mapping from obfuscated to real coordinates. You can find more information and links to further resources on Wikipedia: en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China

      – Tor-Einar Jarnbjo
      6 hours ago






    • 2





      I work for a GIS software company and we looked at some of the online libraries. They were okay for a local area--usually Beijing, not usable for the entire country.

      – mkennedy
      5 hours ago






    • 2





      I opened up a question about the reasoning for this policy on Politics.SE: politics.stackexchange.com/questions/40991/…

      – indigochild
      4 hours ago
















    12














    I am not sure if the context of your question is really on-topic here, but since the answer and its implications is very much relevant for travellers as well, I'll give it a try.



    The explanation you have read is not entirely accurate. The problem is that accurate map material is neither allowed to be published, nor to leave the country. The Chinese National Bureau of Surveying and Mapping require all companies to obtain permits for map surveying and published map data must be obfuscated, resulting in a deviation of up to 700m between the map and the real world. To quote a well-known German children tv show: Sounds strange, but that is how it is.



    You can easily see the result of this obfuscation if you e.g. in Google Maps look at the satellite imagery with a map overlay. It is especially obvious in border proximity, where you will see that the map data for China is skewed, while the map outside China is correct. If you look at this area, the Shenzhen Bay with the border between China and Hong Kong, you can see that the map over Hong Kong in the lower right area is correct, while in the middle of the bay, the map seem to indicate that the bridge makes a sharp bend to the right, while you on the satellite image can see that the bridge in reality is straight. In the upper left area (mainland China), you can then see that there is a significant discrepancy between the imagery and the map. Roads seem to float on the water, pass through buildings and what else not.






    share|improve this answer





















    • 5





      @TimSch The Chinese Surveying and Mapping Law does not explain why the restriction is in place. It is commonly quoted that it is for national security purposes, but I am not really sure if there is any official statement on that subject at all. Similar regulations and restrictions are actually quite common in many other countries as well, but usually do not apply to the entire country, just to 'places of interest'.

      – Tor-Einar Jarnbjo
      9 hours ago








    • 1





      Does china mandate how exactly the skewing will be done? Do they do it themselves or is it the companies' responsibility? Can I get a bunch of maps of china and take an average?

      – OganM
      6 hours ago






    • 4





      @OganM The obfuscation algorithm is prespecified, not publicly known, but obviously deterministic. Since a lot of example data is available, there have been attempts to reverse-engineer the algorithm and there are relatively reliable software libraries available allowing a backwards mapping from obfuscated to real coordinates. You can find more information and links to further resources on Wikipedia: en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China

      – Tor-Einar Jarnbjo
      6 hours ago






    • 2





      I work for a GIS software company and we looked at some of the online libraries. They were okay for a local area--usually Beijing, not usable for the entire country.

      – mkennedy
      5 hours ago






    • 2





      I opened up a question about the reasoning for this policy on Politics.SE: politics.stackexchange.com/questions/40991/…

      – indigochild
      4 hours ago














    12












    12








    12







    I am not sure if the context of your question is really on-topic here, but since the answer and its implications is very much relevant for travellers as well, I'll give it a try.



    The explanation you have read is not entirely accurate. The problem is that accurate map material is neither allowed to be published, nor to leave the country. The Chinese National Bureau of Surveying and Mapping require all companies to obtain permits for map surveying and published map data must be obfuscated, resulting in a deviation of up to 700m between the map and the real world. To quote a well-known German children tv show: Sounds strange, but that is how it is.



    You can easily see the result of this obfuscation if you e.g. in Google Maps look at the satellite imagery with a map overlay. It is especially obvious in border proximity, where you will see that the map data for China is skewed, while the map outside China is correct. If you look at this area, the Shenzhen Bay with the border between China and Hong Kong, you can see that the map over Hong Kong in the lower right area is correct, while in the middle of the bay, the map seem to indicate that the bridge makes a sharp bend to the right, while you on the satellite image can see that the bridge in reality is straight. In the upper left area (mainland China), you can then see that there is a significant discrepancy between the imagery and the map. Roads seem to float on the water, pass through buildings and what else not.






    share|improve this answer















    I am not sure if the context of your question is really on-topic here, but since the answer and its implications is very much relevant for travellers as well, I'll give it a try.



    The explanation you have read is not entirely accurate. The problem is that accurate map material is neither allowed to be published, nor to leave the country. The Chinese National Bureau of Surveying and Mapping require all companies to obtain permits for map surveying and published map data must be obfuscated, resulting in a deviation of up to 700m between the map and the real world. To quote a well-known German children tv show: Sounds strange, but that is how it is.



    You can easily see the result of this obfuscation if you e.g. in Google Maps look at the satellite imagery with a map overlay. It is especially obvious in border proximity, where you will see that the map data for China is skewed, while the map outside China is correct. If you look at this area, the Shenzhen Bay with the border between China and Hong Kong, you can see that the map over Hong Kong in the lower right area is correct, while in the middle of the bay, the map seem to indicate that the bridge makes a sharp bend to the right, while you on the satellite image can see that the bridge in reality is straight. In the upper left area (mainland China), you can then see that there is a significant discrepancy between the imagery and the map. Roads seem to float on the water, pass through buildings and what else not.







    share|improve this answer














    share|improve this answer



    share|improve this answer








    edited 9 hours ago

























    answered 9 hours ago









    Tor-Einar JarnbjoTor-Einar Jarnbjo

    34.4k486126




    34.4k486126








    • 5





      @TimSch The Chinese Surveying and Mapping Law does not explain why the restriction is in place. It is commonly quoted that it is for national security purposes, but I am not really sure if there is any official statement on that subject at all. Similar regulations and restrictions are actually quite common in many other countries as well, but usually do not apply to the entire country, just to 'places of interest'.

      – Tor-Einar Jarnbjo
      9 hours ago








    • 1





      Does china mandate how exactly the skewing will be done? Do they do it themselves or is it the companies' responsibility? Can I get a bunch of maps of china and take an average?

      – OganM
      6 hours ago






    • 4





      @OganM The obfuscation algorithm is prespecified, not publicly known, but obviously deterministic. Since a lot of example data is available, there have been attempts to reverse-engineer the algorithm and there are relatively reliable software libraries available allowing a backwards mapping from obfuscated to real coordinates. You can find more information and links to further resources on Wikipedia: en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China

      – Tor-Einar Jarnbjo
      6 hours ago






    • 2





      I work for a GIS software company and we looked at some of the online libraries. They were okay for a local area--usually Beijing, not usable for the entire country.

      – mkennedy
      5 hours ago






    • 2





      I opened up a question about the reasoning for this policy on Politics.SE: politics.stackexchange.com/questions/40991/…

      – indigochild
      4 hours ago














    • 5





      @TimSch The Chinese Surveying and Mapping Law does not explain why the restriction is in place. It is commonly quoted that it is for national security purposes, but I am not really sure if there is any official statement on that subject at all. Similar regulations and restrictions are actually quite common in many other countries as well, but usually do not apply to the entire country, just to 'places of interest'.

      – Tor-Einar Jarnbjo
      9 hours ago








    • 1





      Does china mandate how exactly the skewing will be done? Do they do it themselves or is it the companies' responsibility? Can I get a bunch of maps of china and take an average?

      – OganM
      6 hours ago






    • 4





      @OganM The obfuscation algorithm is prespecified, not publicly known, but obviously deterministic. Since a lot of example data is available, there have been attempts to reverse-engineer the algorithm and there are relatively reliable software libraries available allowing a backwards mapping from obfuscated to real coordinates. You can find more information and links to further resources on Wikipedia: en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China

      – Tor-Einar Jarnbjo
      6 hours ago






    • 2





      I work for a GIS software company and we looked at some of the online libraries. They were okay for a local area--usually Beijing, not usable for the entire country.

      – mkennedy
      5 hours ago






    • 2





      I opened up a question about the reasoning for this policy on Politics.SE: politics.stackexchange.com/questions/40991/…

      – indigochild
      4 hours ago








    5




    5





    @TimSch The Chinese Surveying and Mapping Law does not explain why the restriction is in place. It is commonly quoted that it is for national security purposes, but I am not really sure if there is any official statement on that subject at all. Similar regulations and restrictions are actually quite common in many other countries as well, but usually do not apply to the entire country, just to 'places of interest'.

    – Tor-Einar Jarnbjo
    9 hours ago







    @TimSch The Chinese Surveying and Mapping Law does not explain why the restriction is in place. It is commonly quoted that it is for national security purposes, but I am not really sure if there is any official statement on that subject at all. Similar regulations and restrictions are actually quite common in many other countries as well, but usually do not apply to the entire country, just to 'places of interest'.

    – Tor-Einar Jarnbjo
    9 hours ago






    1




    1





    Does china mandate how exactly the skewing will be done? Do they do it themselves or is it the companies' responsibility? Can I get a bunch of maps of china and take an average?

    – OganM
    6 hours ago





    Does china mandate how exactly the skewing will be done? Do they do it themselves or is it the companies' responsibility? Can I get a bunch of maps of china and take an average?

    – OganM
    6 hours ago




    4




    4





    @OganM The obfuscation algorithm is prespecified, not publicly known, but obviously deterministic. Since a lot of example data is available, there have been attempts to reverse-engineer the algorithm and there are relatively reliable software libraries available allowing a backwards mapping from obfuscated to real coordinates. You can find more information and links to further resources on Wikipedia: en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China

    – Tor-Einar Jarnbjo
    6 hours ago





    @OganM The obfuscation algorithm is prespecified, not publicly known, but obviously deterministic. Since a lot of example data is available, there have been attempts to reverse-engineer the algorithm and there are relatively reliable software libraries available allowing a backwards mapping from obfuscated to real coordinates. You can find more information and links to further resources on Wikipedia: en.wikipedia.org/wiki/Restrictions_on_geographic_data_in_China

    – Tor-Einar Jarnbjo
    6 hours ago




    2




    2





    I work for a GIS software company and we looked at some of the online libraries. They were okay for a local area--usually Beijing, not usable for the entire country.

    – mkennedy
    5 hours ago





    I work for a GIS software company and we looked at some of the online libraries. They were okay for a local area--usually Beijing, not usable for the entire country.

    – mkennedy
    5 hours ago




    2




    2





    I opened up a question about the reasoning for this policy on Politics.SE: politics.stackexchange.com/questions/40991/…

    – indigochild
    4 hours ago





    I opened up a question about the reasoning for this policy on Politics.SE: politics.stackexchange.com/questions/40991/…

    – indigochild
    4 hours ago













    4














    China has some pretty strict laws (for national security purposes, it seems) related to mapping and geographical surveying, effectively outlawing it for non-nationals.



    See OpenStreetMap's view of the topic.






    share|improve this answer




























      4














      China has some pretty strict laws (for national security purposes, it seems) related to mapping and geographical surveying, effectively outlawing it for non-nationals.



      See OpenStreetMap's view of the topic.






      share|improve this answer


























        4












        4








        4







        China has some pretty strict laws (for national security purposes, it seems) related to mapping and geographical surveying, effectively outlawing it for non-nationals.



        See OpenStreetMap's view of the topic.






        share|improve this answer













        China has some pretty strict laws (for national security purposes, it seems) related to mapping and geographical surveying, effectively outlawing it for non-nationals.



        See OpenStreetMap's view of the topic.







        share|improve this answer












        share|improve this answer



        share|improve this answer










        answered 9 hours ago









        RichardRichard

        1,733517




        1,733517






















            TimSch is a new contributor. Be nice, and check out our Code of Conduct.










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            TimSch is a new contributor. Be nice, and check out our Code of Conduct.
















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