geolocationgpsindoor
I would like to know what are the differences between Positioning and Localization. In most papers they are used interchangeably.
Are they the same?
Does one come after another?
I always thought in this order:
Is this correct?
The problem is poorly documented by authoritative sources for English speakers, despite affecting millions of people on an everyday basis. I've spend the past two days trying to understand the situation and I've created a Wikipedia article about the restrictions on mapping in China and about the China GPS shift problem. Below is the part of my research that answers the question.
The root of the problem is the severe restrictions that the Chinese State Council places on geographic data concerning China's air, land and waters. Mapping and surveying can only be done with authorization from the State Council, and foreigners must form a joint-venture in order to be granted authorization for surveys. There have been numerous examples of fines levied against individuals and companies breaking this (cough protectionist and isolationist cough) law.
Online map providers offering street maps of China must obtain an authorization from the State Council. These maps must use the GCJ-02 datum, instead of the WGS-84 that the most of the world uses. This causes WGS-84 coordinates, such as those coming from a regular GPS chip, to be plotted incorrectly on GCJ-02 maps.
The street maps displayed by both google.com/maps and google.cn/maps use GCJ-02 coordinates. This can be proved by getting the GPS (WGS-84) coordinates of a known landmark, such as the Monument to the People's Heroes in Shanghai, which is located at 31.24427 N, 121.48695 E:
Google.com Maps satellite imagery uses the WGS-84 coordinates, which causes a pretty terrible mismatch:
I'm still unclear as to whether GPS chips manufactured in China return GCJ-02 coordinates directly, or if they return WGS-84 coordinates, which approved map software can convert to GCJ-02.
So your GPS coordinates are far apart? If they are close - eg. short segments along a road, then "straight line" is good enough.
There is an open source extension for PostGIS that can calculate road distances. It is called pgRouting. You will also need to create a road database - typically OpenStreetMaps is used.
Best Answer
The word localization is a new and, in my opinion, an annoying addition to geomatics. The question used to be: What is the difference between positioning and location? Two possible answers to which were:
One context was AVL (automatic vehicle location). In the late '80s, Hassan Karimi coined the term PLANS for "positioning, location and navigation systems". While it didn't catch on, it does relate closely to your question. In that context, positioning was determining coordinates (what the P in GPS stands for), location was finding that place on the map (or the nearest point on a road network to that position), and navigation was finding routes to other places on the network. If that is correct, then you have your 1 and 2 in reverse order.
Now to the (IMO, ugly) word localization. I often see it used in the context of trilateration where position must be determined from multiple distance measurements to control points. In that case it is synonymous with positioning. However, I believe the more common use, especially in IT, of localization is "the process of adapting internationalized software for a specific region or language by adding locale-specific components and translating text." wikipedia