无Web访问的反向地理编码 [英] Reverse Geocoding Without Web Access

问题描述

我正在研究一个应用程序，其中一个要求是我能够基于GPS数据执行实时反向地理编码操作。特别是，我必须能够确定一个经纬度对映射的州/省，并检测我们何时从一个州/省转移到另一州/省。

到目前为止，我有一些想法，但是想知道是否有人对以下任一方面有任何想法：

• 解决此问题的最佳方法是什么问题有效吗？


• 哪里可以找到适合北美洲州/省界限的适当格式

首先，我有两个主要想法：

1. 将北美打入网格中的每个矩形都映射到特定的省份。根据纬度和经度（反之亦然），在这张表格上查找（快速增长，更精确）。
   
2. 为每一个定义多边形状态并进行某种计算来确定经度/纬度对在哪个多边形中。我不确定如何去做这件事。 HTML图像映射让人想起它作为一种为州/省界定界限的方法。

我正在为感兴趣的python工作或者可能有一个很好的库，他们希望建议。

要清楚...我没有可用的Web访问，所以使用现有的反向地理编码服务不是运行时的选项

解决方案

我建议使用您的第一个想法的变体：使用空间索引。空间索引是从矩形构建的数据结构，将纬度/长度映射到有效载荷。在这种情况下，您可能会将矩形映射到省级对。 R-tree 可能是一个不错的选择。这是一个 R-tree python包。您可以通过比较连续搜索的结果来检测漫游。

I am working on an application where one of the requirements is that I be able to perform realtime reverse geocoding operations based on GPS data. In particular, I must be able to determine the state/province to which a latitude, longitude pair maps and detect when we have moved from one state/province to another.

I have a couple ideas so far but wondered if anyone had any ideas on either of the following:

• What is the best approach for tackling this problem in an efficient manner?
• Where is a good place to find and what is the appropriate format for North American state/province boundaries

As a starter, here are the two main ideas I have:

1. Break North America into a grid with each rectangle in the grid mapping to a particular state province. Do a lookup on this table (which grows quickly the more precise you would like to be) based on the latitude and then the longitude (or vice versa).
2. Define polygons for each of the states and do some sort of calculation to determine in which polygon a lat/lon pair lies. I am not sure exactly how to go about this. HTML image maps come to mind as one way of defining the bounds for a state/province.

I am working in python for the interested or those that might have a nice library they would like to suggest.

To be clear... I do not have web access available to me, so using an existing reverse geocoding service is not an option at runtime

解决方案

I suggest using a variant of your first idea: Use a spatial index. A spatial index is a data structure built from rectangles, mapping lat/long to the payload. In this case you will probably map rectangles to state-province pairs. An R-tree may be a good option. Here's an R-tree python package. You could detect roaming by comparing the results of consecutive searches.

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