Realtime export of payload data in KML format.

gateway.c

@@ -23,6 +23,7 @@
 #include "urlencode.h"
 #include "base64.h"
 #include "ssdv.h"
+#include "kml.h"
 #include "global.h"
 
 
@@ -586,6 +587,7 @@ void LoadConfigFile()
 	Config.ftpUser[0] = '\0';
 	Config.ftpPassword[0] = '\0';
 	Config.ftpFolder[0] = '\0';
+	Config.EnableKML = 0;
 
 	if ((fp = fopen(filename, "r")) == NULL)
 	{
@@ -604,6 +606,8 @@ void LoadConfigFile()
 	ReadString(fp, "ftpPassword", Config.ftpPassword, sizeof(Config.ftpPassword), 0);
 	ReadString(fp, "ftpFolder", Config.ftpFolder, sizeof(Config.ftpFolder), 0);	
 
+	ReadBoolean(fp, "EnableKML", 0, &Config.EnableKML);
+
 	for (Channel=0; Channel<=1; Channel++)
 	{
 		// Defaults
@@ -1070,6 +1074,12 @@ int main(int argc, char **argv)
 							DoPositionCalcs(Channel);
 
 							Config.LoRaDevices[Channel].TelemetryCount++;
+							if (Config.EnableKML)
+								UpdatePayloadKML(Config.LoRaDevices[Channel].Payload, Config.LoRaDevices[Channel].Seconds, 
+									Config.LoRaDevices[Channel].Latitude, Config.LoRaDevices[Channel].Longitude, 
+									Config.LoRaDevices[Channel].Altitude);
+
+
 
 							Message[strlen(Message+1)] = '\0';
 							LogMessage("Ch %d: %s\n", Channel, Message+1);
@@ -1111,6 +1121,12 @@ int main(int argc, char **argv)
 							DoPositionCalcs(Channel);
 
 							Config.LoRaDevices[Channel].TelemetryCount++;
+							if (Config.EnableKML)
+								UpdatePayloadKML(Payloads[SourceID].Payload, Config.LoRaDevices[Channel].Seconds, 
+									Config.LoRaDevices[Channel].Latitude, Config.LoRaDevices[Channel].Longitude, 
+									Config.LoRaDevices[Channel].Altitude);
+
+
 
 							LogMessage("Ch %d: Sender %d Source %d (%s) Position %8.5lf, %8.5lf, %05u\n",
 								Channel,

global.h

@@ -40,6 +40,7 @@ struct TConfig
 	char ftpPassword[32];
 	char ftpFolder[64];
 	struct TLoRaDevice LoRaDevices[2];
+	int EnableKML;
 };
 
-extern struct TConfig Config;
+extern struct TConfig Config;

kml.c

@@ -0,0 +1,125 @@
+/* RealTime KML export of the payload data */
+/* Based on https://ukhas.org.uk/using_google_earth */
+
+#include <unistd.h>  	// UNIX standard function definitions
+#include <stdio.h>   	// Standard input/output definitions
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "kml.h"
+#include "global.h"
+
+#define KML_LINE_SIZE 256 //Maximum size of a kml line
+
+/* KML file footer */
+const char footer_str[] = 
+	"        </coordinates>\n" \
+        "      </LineString>\n" \
+       	"    </Placemark>\n" \
+        "  </Document>\n" \
+       	"</kml>\n";
+
+/* Write the header of the KML file for the specified payload */
+void writeHeader(FILE* fp, char * payload) {
+	fprintf(fp,"<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n");
+	fprintf(fp,"  <kml xmlns=\"http://www.opengis.net/kml/2.2\" xmlns:gx=\"http://www.google.com/kml/ext/2.2\" " );
+	fprintf(fp,"  xmlns:kml=\"http://www.opengis.net/kml/2.2\" xmlns:atom=\"http://www.w3.org/2005/Atom\">\n");
+	fprintf(fp,"  <Document>\n	<name>%s</name>\n", payload);
+	fprintf(fp,"    <open>1</open>\n");
+	fprintf(fp,"    <Placemark>\n");
+	fprintf(fp,"      <name>%s-track</name>\n", payload);
+	fprintf(fp,"      <LineString>\n");
+	fprintf(fp,"        <extrude>1</extrude>\n");
+	fprintf(fp,"        <tessellate>1</tessellate>\n");
+	fprintf(fp,"        <altitudeMode>absolute</altitudeMode>\n");
+	fprintf(fp,"        <coordinates>\n");
+
+}
+
+/* Write the footer of the KML file */
+void writeFooter(FILE* fp) {
+	fprintf(fp,"%s", footer_str);
+}
+
+/* Write the KML for refreshing the track of the specified payload */
+void writeRefreshKML(FILE* fp, char * payload) {
+	fprintf(fp,"<kml xmlns=\"http://earth.google.com/kml/2.0\">\n");
+	fprintf(fp,"  <Document>\n");
+	fprintf(fp,"    <NetworkLink>\n");
+	fprintf(fp,"      <name>%s</name>\n", payload);
+	fprintf(fp,"      <Url>\n");
+	fprintf(fp,"        <href>%s.kml</href>\n", payload);
+	fprintf(fp,"        <refreshMode>onInterval</refreshMode>\n");
+	fprintf(fp,"        <refreshInterval>5</refreshInterval>\n");
+	fprintf(fp,"      </Url>\n");
+	fprintf(fp,"    </NetworkLink>\n");
+	fprintf(fp,"  </Document>\n");
+	fprintf(fp,"</kml>\n");
+}
+
+/* Update the KML file of the payload with the specified data */
+void UpdatePayloadKML(char * payload, unsigned int seconds, double latitude, double longitude, unsigned int altitude) {
+	FILE * fp;
+	char filename[256];
+	char line[KML_LINE_SIZE];
+	struct stat st;
+	int res;
+
+	/* Discard empty positions */
+	if (latitude == 0.0 && longitude == 0.0)
+		return;	
+	/* Path to the KML file for this payload */
+	sprintf(filename, "%s.kml", payload);
+
+	/* Check if the KML exists already */
+	res = stat(filename, &st);
+
+	/* Prepare the KML line for the payload data */
+	snprintf(line, KML_LINE_SIZE, "          %f,%f,%d\n", 
+			longitude, latitude, altitude);
+
+	/* If the KML doesn't exists */
+	if (res < 0) {
+		/* Create a KML file which will refresh the payload KML at regular interval */
+		char filename_refresh[256];
+		FILE * fp_refresh;
+		sprintf(filename_refresh, "%s-refresh.kml", payload);
+		fp_refresh = fopen(filename_refresh, "w");
+		if (fp_refresh) {
+			writeRefreshKML(fp_refresh,payload);
+			fclose(fp_refresh);
+		} else {
+			LogMessage("Can't open %s file for writing\n", filename_refresh);
+		}
+		/* Create the KML file for the payload */
+
+		fp = fopen(filename, "a");
+		if (!fp) {
+			LogMessage("Can't open %s file for writing\n", filename);
+			return;
+		} else {
+			LogMessage("Created %s file\n", filename);
+		}
+		/* Add the header, new data line and footer */
+		writeHeader(fp, payload);
+		fwrite(line, 1, strlen(line), fp);
+		writeFooter(fp);
+
+	} else {
+		/* KML already exists : update only the file with new data */
+		fp = fopen(filename, "r+");
+		if (!fp) {
+			LogMessage("Can't open %s file for writing\n", filename);
+			return;
+		}
+		/* Write new data just before the position of the footer in the KML */
+		fseek(fp, -strlen(footer_str), SEEK_END);
+		fwrite(line, 1, strlen(line), fp);
+		writeFooter(fp);
+
+	}
+	fclose(fp);
+}
+
+

kml.h

@@ -0,0 +1,4 @@
+/* RealTime KML export of the payload data */
+/* Based on https://ukhas.org.uk/using_google_earth */
+
+void UpdatePayloadKML(char * payload, unsigned int seconds, double latitude, double longitude, unsigned int altitude);

makefile

@@ -1,15 +1,18 @@
-gateway: gateway.o urlencode.o base64.o ssdv.o ssdv.h global.h
-	cc -o gateway gateway.o urlencode.o base64.o ssdv.o -lm -lwiringPi -lwiringPiDev -lcurl -lncurses -lpthread
-
-gateway.o: gateway.c global.h
-	gcc -c gateway.c
-
-ssdv.o: ssdv.c ssdv.h global.h
-	gcc -c ssdv.c
-
-urlencode.o: urlencode.c
-	gcc -c urlencode.c
-
-base64.o: base64.c
-	gcc -c base64.c
-
+gateway: gateway.o urlencode.o base64.o ssdv.o ssdv.h kml.o global.h
+	cc -o gateway gateway.o urlencode.o base64.o ssdv.o kml.o -lm -lwiringPi -lwiringPiDev -lcurl -lncurses -lpthread
+
+gateway.o: gateway.c global.h
+	gcc -c gateway.c
+
+ssdv.o: ssdv.c ssdv.h global.h
+	gcc -c ssdv.c
+
+urlencode.o: urlencode.c
+	gcc -c urlencode.c
+
+base64.o: base64.c
+	gcc -c base64.c
+
+kml.o: kml.c kml.h global.h
+	gcc -c kml.c
+