KML | Technology Tutorials

In this video lesson we show you how you can transfer data from your Raspberry Pi Pico W GPS Project to your PC for display on Google Earth. This program transfers the Pi Pico GPS Log file to your PC, and as the transfer is done, the program converts the log.txt file into a .kml file for display on Google Earth.

import serial
import time
serialPort = 'COM7'
baudRate = 115200
ser = serial.Serial(serialPort, baudRate, timeout = .1)
time.sleep(1)
ser.write(b"f=open('log.txt','r')\r\n")
line = ser.readline().decode('utf-8').strip()
print("Initial Line: "+line)
time.sleep(.1)
kmlHeader = """<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
  <Document>
    <name>Path from Pico</name>
    <Style id="pointStyle">
      <IconStyle>
        <Icon><href>http://maps.google.com/mapfiles/kml/shapes/placemark_circle.png</href></Icon>
        <scale>1.0</scale>
      </IconStyle>
    </Style>
    <Style id="lineStyle">
      <LineStyle><color>ff0000ff</color><width>3</width></LineStyle>
    </Style>
    <Placemark>
      <styleUrl>#pointStyle</styleUrl>
      <MultiGeometry> """
pointStart = "<Point><coordinates>"
pointEnd = "</coordinates></Point>"
lineStringStart = """ </MultiGeometry>
    </Placemark>
    <Placemark>
      <name>Path</name>
      <styleUrl> #lineStyle</styleUrl>
      <LineString>
        <tessellate>1</tessellate>
        <altitudeMode>clampToGround</altitudeMode>
        <coordinates> """
lineStringEnd = """ </coordinates>
      </LineString>
    </Placemark>
  </Document>
</kml> """
with open('path.kml','w') as kml:
    kml.write(kmlHeader)
with open('lon-lat.txt', 'w') as lonLat:
    pass
with open('path.kml','a') as kml:
    with open('lon-lat.txt','a') as lonLat:
        while line != "''":
            ser.write(b"f.readline()\r\n")
            line = ser.readline().decode('utf-8').strip()
            line = ser.readline().decode('utf-8').strip()
            print("LINE: "+line)
            if line.startswith("'") and line !="''":
                line = line[1:-3]
                myData = line.split(',')
                line = myData[1]+','+myData[0]
                print("New Line: ",line)
                kml.write(pointStart+'\n'+line+ '\n'+pointEnd+'\n')              
                lonLat.write(line+ " "+'\n')
with open('lon-lat.txt','r') as lonLat:
    coordinates = lonLat.read()
print(coordinates)
with open('path.kml','a') as kml:
    kml.write(lineStringStart+'\n'+ coordinates+lineStringEnd)
ser.write(b"f.close()\r\n")
ser.close()
print("KML File Saved as "+ 'path.kml')

import serial

import time

serialPort = 'COM7'

baudRate = 115200

ser = serial.Serial(serialPort, baudRate, timeout = .1)

time.sleep(1)

ser.write(b"f=open('log.txt','r')\r\n")

line = ser.readline().decode('utf-8').strip()

print("Initial Line: "+line)

time.sleep(.1)

kmlHeader = """<?xml version="1.0" encoding="UTF-8"?>

<Icon><href>http://maps.google.com/mapfiles/kml/shapes/placemark_circle.png</href></Icon>

</IconStyle>

</Style>

</Style>

<styleUrl>#pointStyle</styleUrl>

<MultiGeometry> """

pointStart = "<Point><coordinates>"

pointEnd = "</coordinates></Point>"

lineStringStart = """ </MultiGeometry>

</Placemark>

<styleUrl> #lineStyle</styleUrl>

<altitudeMode>clampToGround</altitudeMode>

<coordinates> """

lineStringEnd = """ </coordinates>

</LineString>

</Placemark>

</Document>

</kml> """

with open('path.kml','w') as kml:

kml.write(kmlHeader)

with open('lon-lat.txt', 'w') as lonLat:

pass

with open('path.kml','a') as kml:

with open('lon-lat.txt','a') as lonLat:

while line != "''":

ser.write(b"f.readline()\r\n")

line = ser.readline().decode('utf-8').strip()

print("LINE: "+line)

if line.startswith("'") and line !="''":

line = line[1:-3]

myData = line.split(',')

line = myData[1]+','+myData[0]

print("New Line: ",line)

kml.write(pointStart+'\n'+line+ '\n'+pointEnd+'\n')

lonLat.write(line+ " "+'\n')

with open('lon-lat.txt','r') as lonLat:

coordinates = lonLat.read()

print(coordinates)

with open('path.kml','a') as kml:

kml.write(lineStringStart+'\n'+ coordinates+lineStringEnd)

ser.write(b"f.close()\r\n")

ser.close()

print("KML File Saved as "+ 'path.kml')

Below we show you an example KML file that allows you too display your logged GPS data on Google Earth. For simplicity, we have included two GPS points. First, notice that the ordered pairs are Longitude,Latitude. Notice this is reversed of what we would normally expect, but it is important to note the order . . . Longitude must be put as the first term in the ordered pair. Also notice that the ordered pair of data show up two times in the file. The first is to create the dot, or placemark on the map, and the second list creates the line over your logged path. Now, the challenge for you is to write a python program that takes your log.txt file, which contains simple comma delimited data, lat,lon, and use that to generate a .kml file as shown below.

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2">
  <Document>
    <name>Path from Pico</name>
    <Style id="pointStyle">
      <IconStyle>
        <Icon><href>http://maps.google.com/mapfiles/kml/shapes/placemark_circle.png</href></Icon>
        <scale>1.0</scale>
      </IconStyle>
    </Style>
    <Style id="lineStyle">
      <LineStyle><color>ff0000ff</color><width>3</width></LineStyle>
    </Style>
    <Placemark>
      <styleUrl>#pointStyle</styleUrl>
      <MultiGeometry>
<Point><coordinates>
33.16453,0.47860332
</coordinates></Point>
<Point><coordinates>
33.164512,0.478673336
</coordinates></Point>
</MultiGeometry>
    </Placemark>
    <Placemark>
      <name>Path</name>
      <styleUrl>#lineStyle</styleUrl>
      <LineString>
        <tessellate>1</tessellate>
        <altitudeMode>clampToGround</altitudeMode>
        <coordinates>
33.16453,0.47860332 
33.164512,0.478673336 
</coordinates>
      </LineString>
    </Placemark>
  </Document>
</kml>

<?xml version="1.0" encoding="UTF-8"?>

<Icon><href>http://maps.google.com/mapfiles/kml/shapes/placemark_circle.png</href></Icon>

</IconStyle>

</Style>

</Style>

<styleUrl>#pointStyle</styleUrl>

33.16453,0.47860332

</coordinates></Point>

33.164512,0.478673336

</coordinates></Point>

</MultiGeometry>

</Placemark>

<styleUrl>#lineStyle</styleUrl>

<altitudeMode>clampToGround</altitudeMode>

33.16453,0.47860332

33.164512,0.478673336

</coordinates>

</LineString>

</Placemark>

</Document>

</kml>

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Technology Tutorials

Tag Archives: KML

Python Program to Convert GPS Log file into a KML File for Display on Google Earth

Create a KML File to Display your GPS Data on Google Earth

Making The World a Better Place One High Tech Project at a Time. Enjoy!