[英]Calculate point distance in postgis/postgresql
I am trying to calculate the distances between points in PostgreSQL, and now I have the longitude and latitude value for each point, and I know it's from GPS(WGS84). 我正在尝试计算PostgreSQL中点之间的距离,现在我有每个点的经度和纬度值,我知道它来自GPS(WGS84)。
Because all the points are in same city, and not very far from each other, so I know that use geometry with a local cartesian projection is better, because compared with using geography, it needs less calculation. 因为所有的点都在同一个城市,并且相距不太远,所以我知道使用具有局部笛卡尔投影的几何更好,因为与使用地理相比,它需要更少的计算。
My question is how can I find the suitable cartesian projection for my data? 我的问题是如何才能为我的数据找到合适的笛卡尔投影? If I can find one, is it the SRID value which should be used in
ST_Transform
? 如果我能找到一个,是否应该在
ST_Transform
使用SRID值?
Thank you very much! 非常感谢你!
I have found the SRID I need in this page: http://help.arcgis.com/en/arcgisserver/10.0/apis/rest/pcs.html and this page: http://help.arcgis.com/en/arcgisserver/10.0/apis/rest/gcs.html , and use ST_Transform to transfer the WGS84 coordinate to local cartesian coordinate, and can get the distance result in Unit meter. 我在此页面中找到了我需要的SRID: http : //help.arcgis.com/en/arcgisserver/10.0/apis/rest/pcs.html和此页面: http : //help.arcgis.com/en/ arcgisserver / 10.0 / apis / rest / gcs.html ,并使用ST_Transform将WGS84坐标传递到本地笛卡尔坐标,并可以得到单位米的距离结果。
Hope this can help others :) 希望这可以帮助别人:)
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