我在Postgres上有一个我没有建立的网站上的距离计算。
我编写了在php中插入新位置的脚本，因为我知道php更好的红宝石。
我想弄清楚如何为位置插入新的几何点。
我尝试使用以下内容，但我在点之间得到了8000英里......
数据库中的当前点与距离有关...但我尝试插入的任何新点都会得到错误的距离。即使我添加2个新点来检查：
我使用以下代码与城市州的csv文件和zipcodes重建数据库：
示例文件：
2832 Hope Valley RI
2833 Hopkinton RI
2835 Jamestown RI
2836 Kenyon RI
2837 Little Compton RI
2838 Manville RI
2839 Mapleville RI
2840 Newport RI
2841 Newport RI
2842 Middletown RI
2852 North Kingstown RI
2854 North Kingstown RI
2857 North Scituate RI
2858 Oakland RI
2859 Pascoag RI
2860 Pawtucket RI
2861 Pawtucket RI
2862 Pawtucket RI
2863 Central Falls RI
2864 Cumberland RI
2865 Lincoln RI
2871 Portsmouth RI
2872 Prudence Island RI
2873 Rockville RI
2874 Saunderstown RI
2875 Shannock RI
2876 Slatersville RI
2877 Slocum RI
2878 Tiverton RI
2879 Wakefield RI
2880 Wakefield RI
2881 Kingston RI
2882 Narragansett RI
2883 Peace Dale RI
2885 Warren RI
2886 Warwick RI
2887 Warwick RI
我的PHP插入代码
$content = file($selectfile1);
$posted_content = array();
list($rownum, $row) = each($content);
$posted_content[0] = explode(",", $row);
array_push($posted_content[0], "ID");
$count = 0;
$error = 0;
// iterate each row (1 post)
while (list($rownum, $row) = each($content))
{
$count++;
// extract fields from row columns
$items = explode(",", $row);
list($zip, $city1, $state1) = $items;
array_push($posted_content, $items);
$getHTML ="http://dev.virtualearth.net/REST/v1/Locations/" . $zip . "?o=xml&key=AvtYnvs3UjKaIPdG5v1YaVBL_5-Rhg_zgUwoQgvTiTS9dMxJSreIanWVLvTzQc86";
$getHTML1 ="http://dev.virtualearth.net/REST/v1/Locations/" . $city . "," .$state . "?o=xml&key=AvtYnvs3UjKaIPdG5v1YaVBL_5-Rhg_zgUwoQgvTiTS9dMxJSreIanWVLvTzQc86";
// get the response from the Locations API and store it in a string
$output = file_get_contents($getHTML);
// create an XML element based on the XML string
$response = new SimpleXMLElement($output);
// Extract data (e.g. latitude and longitude) from the results
$lat = $response->ResourceSets->ResourceSet->Resources->Location->Point->Latitude;
$lng = $response->ResourceSets->ResourceSet->Resources->Location->Point->Longitude;
$lat1 = RTRIM($lat);
$lat2 = LTRIM($lat1);
$lng1 = RTRIM($lng);
$lng2 = LTRIM($lng1);
//$getJSON = "http://maps.googleapis.com/maps/api/geocode/json?address=" . $zip . "&sensor=false";
//$contentJSON = file_get_contents($getJSON);
//$Geocode_array = json_decode($contentJSON, true);
//$lat = $Geocode_array['results'][0]['geometry']['location']['lat'];
//$lng = $Geocode_array['results'][0]['geometry']['location']['lng'];
reset($response);
if(empty($lat2) || empty($lng2))
{
echo "<b>Error:</b>" . $city1 . ", " . $state1 . " " . $zip . "<br>";
$error++;
continue;
}
$vals = "ST_GeographyFromText('POINT(" . $lat2 . " " . $lng2 . ")')";
$sql = "UPDATE locations SET coords =". $vals . " where zip ='" . $zip . "'";
$rs = $conn->Execute($sql);
if ($rs === false) die('Insert error: ' . $city . ', ' . $state . ' ' . $conn->ErrorMsg() . " SQL: " . $sql);
}
echo $error;
reset($content);
unset($GLOBALS["_SESSION"]["szContent"]);
我已尝试过以下方法，但没有一个能够正确进行距离计算（红宝石编码中的计算代码如下）
$vals = "ST_GeographyFromText('POINT(" . $lat2 . " " . $lng2 . "), 4326')";
$vals = "ST_GeographyFromText('SRID=4326; POINT(" . $lat2 . " " . $lng2 . ")')";
这是我插入的数据库表：
CREATE TABLE locations
(
id serial NOT NULL,
coords geography(Point,4326),
city character varying(255),
state character varying(255),
zip character varying(255),
created_at timestamp without time zone NOT NULL,
updated_at timestamp without time zone NOT NULL,
cs character varying(255),
alt text,
CONSTRAINT locations_pkey PRIMARY KEY (id)
)
WITH (
OIDS=FALSE
);
ALTER TABLE locations
OWNER TO postgres;
GRANT ALL ON TABLE locations TO postgres;
GRANT ALL ON TABLE locations TO loadmax;
-- Index: index_locations_on_coords
-- DROP INDEX index_locations_on_coords;
CREATE INDEX index_locations_on_coords
ON locations
USING gist
(coords);
Ruby编码计算我的ruby网站上的距离...
class Location < ActiveRecord::Base
attr_accessible :city, :coords, :state, :zip
set_rgeo_factory_for_column(:coords, RGeo::Geographic.spherical_factory(:srid => 4326))
def self.validate_cs_and_return_proper(location)
return "ANYWHERE" if location.upcase == "ANYWHERE" || location.nil? || location == ""
state = location[-2,2]
city = location.gsub(%r(, [a-zA-Z]+), '').strip
l = first(:conditions => {:city => city.downcase, :state => state.downcase})
if l.nil?
new_l = where("(levenshtein(city, '#{city}') <= 4) AND state = '#{state}'").order("levenshtein(city, '#{city}') ASC").first
return "#{new_l.city}, #{new_l.state}"
else
return location
end
end
def self.city_state_exists?(location)
return true if location.upcase == "ANYWHERE" || location.nil? || location == ""
state = location[-2,2]
city = location.gsub(%r(, [a-zA-Z]+), '').strip
l = first(:conditions => {:city => city.downcase, :state => state.downcase})
if l.nil?
new_l = where("(levenshtein(city, '#{city}') <= 4) AND state = '#{state}'").order("levenshtein(city, '#{city}') ASC").first
return true unless new_l.blank?
return false
else
return true
end
end
def self.to_point(location)
return location unless location.class == String
return nil if location.upcase=='ANYWHERE'
state = location[-2,2]
city = location.gsub(%r(, [a-zA-Z]+), '').strip
l = first(:conditions => {:city => city.downcase, :state => state.downcase})
l.coords
end
def self.to_cs(point)
return "ANYWHERE" if point.nil? || (point.x == 0.0 && point.y == 0.0)
l = first(:conditions => {:coords => point})
l[:state] = l[:state].upcase
c_parts = l[:city].split(" ")
c_parts.each {|part| part.capitalize! }
l[:city] = c_parts.join(" ")
return "#{l[:city]}, #{l[:state].upcase}"
end
def self.city_state(point)
return "ANYWHERE" if point.nil? || (point.x == 0.0 && point.y == 0.0)
city_state = {}
l = first(:conditions => {:coords => point})
city_state[:city] = l[:city]
city_state[:state] = l[:state]
city_state
end
def self.distance_between(locale_one, locale_two)
#locale_one and locale_two must be points
select = "ST_Distance(gg1, gg2)"
from = "(SELECT ST_GeographyFromText('#{locale_one}') AS gg1, ST_GeographyFromText('#{locale_two}') AS gg2) AS foo"
distance = Location.select(select).from(from)
#1609.344 is how many meters are in a mile
"%.2f" % (distance[0].st_distance.to_f/1609.344)
end
def self.check_unknown(cs)
report = Report.first( :conditions => { :metric => "unknown_locations", :name => cs } )
#i.e. if it's been tried 25 times, add it to the locations table.
if report.value > 5
city, state = cs.split(",")
state = state.strip
google_api_results = HTTParty.get("http://maps.googleapis.com/maps/api/geocode/json?address=#{cs.gsub(/ /, "%20")}&sensor=true")
geo_data = google_api_results.parsed_response
lat = geo_data["results"][0]["geometry"]["location"]["lat"]
lng = geo_data["results"][0]["geometry"]["location"]["lng"]
l = Location.new({
:city => city,
:state => state,
:coords => "ST_GeographyFromText('POINT( #{lat} #{lng} )')",
:cs => "#{city}, #{state}"
})
l.save
Report.delete(report.id)
return l
else
return false
end
end
end
答案 0 :(得分：2)
轴顺序很重要。如果假设输入是（lat lng），（并且我不会责怪大多数人这样思考的话），你会得到意想不到的结果：
SELECT ST_AsLatLonText('POINT(37.215396881103516 -93.295166015625)');
86°42'17.402"S 142°47'4.571"W或南极洲的La Gorce山脉
将它们交换到（lng lat）：
SELECT ST_AsLatLonText('POINT(-93.295166015625 37.215396881103516)');
37°12'55.429"N 93°17'42.598"W或400-504 W Chestnut Expy Springfield，MO 65801，USA
为PostGIS使用正确的轴顺序，即（X Y）或（长纬度）。因此使用：
$vals = "ST_GeographyFromText('POINT(" . $lng2 . " " . $lat2 . ")')"