The Web Mercator Projection

Author(s):  
İbrahim Öztuğ BİLDİRİCİ ◽  
Osman Sami KIRTILOĞLU
Keyword(s):  
2021 ◽  
Vol 20 (35) ◽  
pp. 30-47
Author(s):  
Miljenko Lapaine ◽  
Nedjeljko Frančula

The Web Mercator projection is a projection of a relatively recent date. There has been a lot of controversy about its application. Some believe that this projection is not a projection of either the sphere or the surface of the ellipsoid. Therefore, in this paper, several projections of the surface of a rotational ellipsoid into a plane are investigated and it is shown that the Web Mercator projection is one of such projections. Namely, although the equations of this projection are identical to the equations for the projection of the sphere, the basic difference is in the choice of the area of definition, i.e., the domain of the projection. Furthermore, we have shown that the Web Mercator projection can also be interpreted as double mapping: mapping an ellipsoid to a sphere according to the normals and then mapping the sphere to the plane according to the formulas of the Mercator projection for the sphere. The Web Mercator projection is not a conformal projection, but it is close in properties to the Mercator projection.


2019 ◽  
Vol 8 (3) ◽  
pp. 125 ◽  
Author(s):  
Lieselot Lapon ◽  
Philippe De Maeyer ◽  
Nina Vanhaeren ◽  
Sarah Battersby ◽  
Kristien Ooms

For decades, cartographers and cognitive scientists have speculated about the influence of map projections on mental representations of the world. The development of Web 2.0 and web mapping services at the beginning of the 21st century—such as Google Maps, OpenStreetMap, and Baidu Map—led to an enormous spread of cartographic data, which is available to every Internet user. Nevertheless, the cartographic properties of these map services, and, in particular, the selected map projection or the Web Mercator projection, are questionable. The goal of this study is to investigate if the global-scale mental map of young people has been influenced by the increasing availability of web maps and the Web Mercator projection. An application was developed that allowed participants of Belgium and the US to scale the land area of certain countries and continents compared to Europe or the conterminous United States. The results show that the participants’ estimation of the actual land area is quite accurate. Moreover, an indication of the existence of a Mercator effect could not be discovered. To conclude, the young people’s mental map of the world does not appear to be influenced by a specific map projection but by personal characteristics. These elements are varied and require further analysis.


2008 ◽  
Vol 11 (2) ◽  
pp. 83-85
Author(s):  
Howard Wilson
Keyword(s):  

2005 ◽  
Vol 8 (1) ◽  
pp. 16-18
Author(s):  
Howard F. Wilson
Keyword(s):  

1999 ◽  
Vol 3 (2) ◽  
pp. 6-6
Author(s):  
Barbara Shadden
Keyword(s):  

2008 ◽  
Vol 18 (1) ◽  
pp. 9-20 ◽  
Author(s):  
Mark Kander ◽  
Steve White

Abstract This article explains the development and use of ICD-9-CM diagnosis codes, CPT procedure codes, and HCPCS supply/device codes. Examples of appropriate coding combinations, and Coding rules adopted by most third party payers are given. Additionally, references for complete code lists on the Web and a list of voice-related CPT code edits are included. The reader is given adequate information to report an evaluation or treatment session with accurate diagnosis, procedure, and supply/device codes. Speech-language pathologists can accurately code services when given adequate resources and rules and are encouraged to insert relevant codes in the medical record rather than depend on billing personnel to accurately provide this information. Consultation is available from the Division 3 Reimbursement Committee members and from [email protected] .


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