php - PostgreSQL select query (GPS) -


the problem!

i have postgresql database on saving gps data of cars. i'm preparing history report , have show 2 different stutus each car according speed, firs stoped if car speed remains 0 within 5 minutes, if more 5 minutes have show parking. data gps on each 10 seconds. there way that? appreciated.

here table structure: 

create table gps_data_abl_soft (   id bigint not null default nextval('gps_data_id_seq'::regclass),   device_id bigint not null default (-1),   keyword character varying(30),   coordinate geometry,   date_time timestamp without time zone not null default now(),   message character varying(200) not null default ''::character varying,   speed real not null default 0.0,   angle real not null default 0.0,   constraint gps_data_pkey primary key (id) )

here sample data table:

i have tackled problem myself creating postgresql function! 

-- function: stop_func(bigint)  -- drop function stop_func(bigint);  create or replace function stop_func(in device_id_param bigint)   returns table(coordinate geometry, difference interval) $body$ declare     r record;     stop_records stop_record[];     speed_zero boolean;     prev_date_time timestamp;     coordinate geometry; begin      speed_zero:=false;      r in select g.coordinate, g.date_time, g.speed gps_data_abl_soft g g.device_id=device_id_param  order g.date_time     loop         if r.speed=0             if not speed_zero prev_date_time:=r.date_time; coordinate=r.coordinate; end if;              speed_zero:=true;         else              if speed_zero                  stop_records=array_append(stop_records,(coordinate, r.date_time-prev_date_time)::stop_record);             end if;              speed_zero:=false;          end if;      end loop;     return query select * unnest(stop_records);    end $body$   language plpgsql volatile   cost 100   rows 1000; alter function stop_func(bigint)   owner dr;

usage of function

 select st_asgeojson(st_transform(st_multi(st_union(coordinate)), 4326)) coordinate,    difference stop_func(device_id, start_time, end_time) group difference;

sample result here:

enter image description here


Comments

Post a Comment

Popular posts from this blog

python Tkinter Capturing keyboard events save as one single string -

is possible store keyboard events 1 string? code below stores 1 char , prints it. card reader or bar code reader, contains collection of character/ string not 1 character @ time. goal save char pressed text variable. from tkinter import * root = tk() def key(event): text= event.char text+= event.char print ("pressed", text) def callback(event): frame.focus_set() print ("clicked at", event.x, event.y) frame = frame(root, width=100, height=100) frame.bind("<key>", key) frame.bind("<button-1>", callback) frame.pack() root.mainloop() currently, creating text variable , everytime key() function gets called, , text stores last character typed. you can define text module level variable , , use module level text inside key function - text = '' def key(event): global text text+= event.char print("pressed", text)
Read more

android - InAppBilling registering BroadcastReceiver in AndroidManifest -

i'm implementing inapp billing in android app. works well, however, i'm trying decouple broadcast receiver activity manifest. suggestion in android's trivialdrive sample: // important: dynamically register broadcast messages updated purchases. // register receiver here instead of <receiver> in manifest // because call getpurchases() @ startup, therefore can ignore // broadcasts sent while app isn't running. // note: registering listener in activity bad idea, done here // because sample. regardless, receiver must registered after // iabhelper setup, before first call getpurchases(). currently there's class extends broadcastreceiver : public class iabbroadcastreceiver extends broadcastreceiver { /** * intent action receiver should filter for. */ public static final string action = "com.android.vending.billing.purchases_updated"; private final iabbroadcastlistener mlistener; public iabbroadcastreceiver(iabbroadcastlistener listener) { m
Read more

javascript - Z-index in d3.js -

i have map , when hover effect on region of map below yellow line , circle, last ones disappear. how can solve problem? http://jsfiddle.net/ot21n9qx/ var arc = g.append("path") .style("fill", "none") .style("stroke", "yellow") .style("stroke-width", 2) .attr("d", "m" + pathorigin[0] + "," + pathorigin[1] + " q" + svgpoint[0] + "," + pathorigin[1] + " " + svgpoint[0] + "," + svgpoint[1]); var circlesize = d3.scale.linear() .domain([0, 0.5, 1]) .range([4, 10, 4]); svg not have z order draws objects in order created. need create path , circle after create highlight regions. here forked fiddle: http://jsfiddle.net/o00fzgaf/1/
Read more