Delphi Call Baidu Map WebService convert GPS coordinates turn

Baidu Map API Description How to use

The first step, the application of the key (AK), as the basis for accessing the service;

Second, follow the request parameter description to send the URL of the HTTP request, note the need to use the first step of the AK application;

The third step is to receive the returned data (in JSON or XML format).

Note: This interface supports callbacks.

Service Address

Http://api.map.baidu.com/geoconv/v1/?

Composition Description:

• Domain Name: http://api.map.baidu.com
• Service Name: Geoconv
• Service version number: v1

Service parameter Description

Parameters	meaning	range of Values	whether you must	Default Value
Coords	SOURCE coordinates	Format: Longitude, latitude, longitude, latitude ... Limit: up to 100 supported Examples of formats: 114.21892734521,29.575429778924; 114.21892734521,29.575429778924	Is	No
Ak	Developer Key		Is	No
sn	User's permission signature		Whether	This parameter must be used if the user is using the AK Check mode for SN check. (SN generation algorithm)
From	source Coordinate type	The values are as follows: The angular coordinates obtained by the 1:GPS device; 2:gps obtained by the metric coordinates, sogou map coordinates used; 3:google map, Soso map, Aliyun map, mapabc map and AMAP map coordinates Metric coordinates for list map coordinates in 4:3 5: Baidu map using latitude and longitude coordinates 6: Baidu map using the metric coordinate system 7:mapbar map coordinates; 8:51 Map coordinates	Whether	The default is 1, which is the coordinates acquired by the GPS device
To	Destination coordinate type	There are two options available: 5, 6. 5:bd09ll (Baidu latitude and longitude coordinates), 6:BD09MC (Baidu metric system latitude and longitude coordinates);	Whether	The default is 5, which is bd09ll (Baidu coordinates)
Output	return result format	JSON or XML	Whether	Json

Return value Description

name		type	meaning	range of Values
Status		Init	Status code	Normal 0, abnormal non 0, detailed status code description
Result		JSON or XML array	Conversion results	Consistent with input order
	X	Float	Abscissa
	Y	Float	Ordinate

Delphi's Invocation process

Procedure Gpstobaidu (Gx,gy:real;var bx,by:real);
Const
urs1= ' http://api.map.baidu.com/geoconv/v1/?coords= ';
Urs2= ' &&ak= your secret key ';//Two &&
Var
url:string;
Ts:tstringstream;
Jo:isuperobject;
Xy:tsuperarray;
Begin
Url:=urs1+floattostr (Gx) + ', ' +floattostr (Gy) +urs2;
Ts:=tstringstream.create;
Try
Idhttp1.get (Url,ts);
Ts. position:=0;
Jo:=so (TS. datastring);
xy:=jo[' result '. Asarray;
Jo:=so (Xy[0]. asstring);
bx:=jo[' x ']. asdouble;
by:=jo[' y ']. asdouble;
Except//conversion failed
BX:=GX;
By:=gy;
Exit
End
End

Delphi Call Baidu Map WebService convert GPS coordinates turn