string conversion problems - the method is not applicable for the arguments

dwarrenku

string conversion problems - the method is not applicable for the arguments

in Contributed Library Questions • 6 months ago

Hi all,

I'm creating a tool to track a weather balloon, but I'm stuck on a pretty basic part: drawing a line.

I have the file of fake GPS info being read to mimic the serial input, and then display the information in a line on the map created by googlemapper. I keep getting this error: "The method line(float, float, float, float) in the type PApplet is not applicable for the arguments (double, double, double, double)" and I know it's because of the doubles not working well with the draw function. How can I convert things so that this works?

The googlemapper library returns a double, but how can I convert this since everything I've tried so far returns "Type mismatch: cannot convert from double to int"

Here is my code:

Copy code

BufferedReader reader;
import googlemapper.*;
import controlP5.*;
import guicomponents.*;
double mapCenterLat = 42.66656;
double mapCenterLon = -72.4831;
int zoomLevel =15;
String mapType = GoogleMapper.MAPTYPE_ROADMAP;
int mapWidth=640;
int mapHeight=480;
String inBuffer;
Boolean isGPSActive;
ArrayList<Double> lat ;
ArrayList<Double> lng ;
Double newLat;
Double newLng;
ControlP5 cp5;
int zoomSlider=7;
Slider abc;
PImage map;
GoogleMapper gMapper;
public void setup() {
//start reading the file with fake info
reader = createReader("C:/Documents and Settings/DWarren/My Documents/Processing/googlemapper_testing/fakegps.txt");
//sets the window size to 640x480
size(640, 480);
//creates new controls using the P5 Library
cp5 = new ControlP5(this);
cp5.addSlider("zoomSlider")
.setPosition(50, 100)
.setSize(40, 200)
.setRange(3, 21)
.setNumberOfTickMarks(9);
cp5.addButton("refresh")
.setValue(0)
.setPosition(50, 80)
.setSize(40, 19);
//sets the zoomlevel
zoomLevel=zoomSlider;
//loads the google map
gMapper = new GoogleMapper(mapCenterLat, mapCenterLon, zoomLevel, mapType, mapWidth, mapHeight);
//loads it to cache
map = gMapper.getMap();
//displays it
image(map, 0, 0);
}
long interval = millis();
//function to run when refresh button is pressed
public void refresh(int theValue) {
println("refreshing map");
try {
interval = millis();
zoomLevel=zoomSlider;
gMapper = new GoogleMapper(mapCenterLat, mapCenterLon, zoomLevel, mapType, mapWidth, mapHeight);
map = gMapper.getMap();
image(map, 0, 0);
}
catch(Exception e) {
e.printStackTrace();
}
}
void draw() {
try {
String inBuffer = reader.readLine();
}
catch (IOException e) {
e.printStackTrace();
inBuffer = null;
}
//String inBuffer = myPort.readString();
println(inBuffer);
String[] op = inBuffer.split(",");
//only when we get valid data, split it to get coordinates
if (op.length==6) {
newLat = Double.valueOf(op[0]); //get latitude
newLng = Double.valueOf(op[1]); //get longitude
lat.add(newLat);
lng.add(newLng);
isGPSActive=true;
}
for (int i=0; i < lat.size() ; i++)
{
double lat1 = gMapper.lat2y(lat.get(i));
double lng1 = gMapper.lon2x(lng.get(i));
double lat2 = gMapper.lat2y(lat.get(i+1));
double lng2 = gMapper.lon2x(lng.get(i+1));
line(lat1,lng1,lat2,lng2);
}
}

Replies(3)

pauline303

Re: string conversion problems - the method is not applicable for the arguments

6 months ago

would this help ?

Copy code

int x;
double mapCenterLat = 42.66656;
x = (int)(mapCenterLat);
println(x);

GoToLoop

Re: string conversion problems - the method is not applicable for the arguments

6 months ago

Different from regular Java's standard, Processing prefers to use data-type float

rather than double for fractional values.

Any drawing function accepts float values as arguments. And normally, Java language doesn't auto-convert

a higher precision type like double to a lower float one. So it has to be done manually!

So, I believe that exception happens in line #97, right?

The best performance solution is to use a (cast) operator using a primitive type.

In your case you can choose n1 from below for drawing function argument purposes:

(float) [4-byte fractional value]
(long) [-2^63 ~ 2^31 - 1] {8 bytes}
(int) [-2^31 ~ 2^31 - 1] {4 bytes}
(char) [0 ~ 2^16 - 1] {2 bytes} (can't be negative)
(short) [-2^15 ~ 2^15 - 1] {2 bytes}

That is, everything but (byte) & (boolean), b/c a 1 byte range isn't enough for a screen coordinate.

And (double) would be redundant of course!

short lat1 = (short) gMapper.lat2y( lat.get(i) );
char  lng1 = (char)  gMapper.lon2x( lng.get(i) );
long  lat2 = (long)  gMapper.lat2y( lat.get(i+1) );
float lng2 = (float) gMapper.lon2x( lng.get(i+1) );

line(lat1, lng1, lat2, lng2);

dwarrenku

Re: string conversion problems - the method is not applicable for the arguments

6 months ago

That was an awesome response, thanks for making it so clear. It fixed my problem.

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