Convert array to string after "for loop" is finished

[Steve]

I am having problems getting values out of an array. The array is set
as a global array and values are pushed into it as they are read from
a JSON file using a "for loop". When the "for loop" is finished I want
to convert the array into a string which can be used by another
function. My attempt to do this is not working. The script looks like
this:

heights=[];
function getElevationInt er(latv,lngv) {
var script = document.create Element('script ');
document.body.a ppendChild(scri pt);
script.src = 'http://ws.geonames.org/srtm3JSON?lat=' + latv +
'&lng=' + lngv + '&callback=load JSON';
}

function loadJSON(result ) {
heights.push(re sult.srtm3);
}

function getProfile() {
var dLat = lat[2]-lat[1];
var dLng = lng[2]-lng[1];
for (var i=0; i<d; i+=0.5) {
var latPoints = parseFloat((lat[1] + dLat*i/d)/10);
var lngPoints = parseFloat((lng[1] + dLng*i/d))/10;
getElevationInt er(latPoints,ln gPoints);
}
//alert(i)
if (i>d) {
alert(heights[2])
heightString=he ights.toString( )
alert(heightStr ing)
}
}

Strangely, if I remove the comment // from the alert(i) the script
sometimes works but with the alert(i) commented out it never works.
The alert(heights[2] is there as a test, it is usually undefined
except sometimes when the alert(i) is uncommented when it returns the
correct value.

I would be grateful for any assistance.

[Doug Gunnoe]

On Jun 22, 4:20 pm, Steve <stephen.jo...@ googlemail.comw rote:

I am having problems getting values out of an array. The array is set
as a global array and values are pushed into it as they are read from
a JSON file using a "for loop". When the "for loop" is finished I want
to convert the array into a string which can be used by another
function. My attempt to do this is not working. The script looks like
this:

heights=[];
function getElevationInt er(latv,lngv) {
var script = document.create Element('script ');
document.body.a ppendChild(scri pt);
script.src = 'http://ws.geonames.org/srtm3JSON?lat=' + latv +
'&lng=' + lngv + '&callback=load JSON';

}

function loadJSON(result ) {
heights.push(re sult.srtm3);

}

function getProfile() {
var dLat = lat[2]-lat[1];
var dLng = lng[2]-lng[1];
for (var i=0; i<d; i+=0.5) {
var latPoints = parseFloat((lat[1] + dLat*i/d)/10);
var lngPoints = parseFloat((lng[1] + dLng*i/d))/10;
getElevationInt er(latPoints,ln gPoints);
}
//alert(i)
if (i>d) {
alert(heights[2])
heightString=he ights.toString( )
alert(heightStr ing)
}

}

Strangely, if I remove the comment // from the alert(i) the script
sometimes works but with the alert(i) commented out it never works.
The alert(heights[2] is there as a test, it is usually undefined
except sometimes when the alert(i) is uncommented when it returns the
correct value.

I would be grateful for any assistance.

Do you have a local variable in any function in your script 'http://
ws.geonames.org/srtm3JSON' named heights?

If so, try using the var keyword for your global above. 'var
heights=[]' instead of just 'heights=[]'.

The following paragraph was taken from here
http://developer.mozilla.org/en/docs...Statements:var

Using var outside a function is optional; assigning a value to an
undeclared variable implicitly declares it as a global variable.
However, it is recommended to always use var, and it is necessary
within functions in the following situations:

* If a variable in a scope containing the function (including the
global scope) has the same name.
* If recursive or multiple functions use variables with the same
name and intend those variables to be local.

Failure to declare the variable in these cases will very likely lead
to unexpected results.

[Doug Gunnoe]

On Jun 22, 4:20 pm, Steve <stephen.jo...@ googlemail.comw rote:

I am having problems getting values out of an array. The array is set
as a global array and values are pushed into it as they are read from
a JSON file using a "for loop". When the "for loop" is finished I want
to convert the array into a string which can be used by another
function. My attempt to do this is not working. The script looks like
this:

heights=[];
function getElevationInt er(latv,lngv) {
var script = document.create Element('script ');
document.body.a ppendChild(scri pt);
script.src = 'http://ws.geonames.org/srtm3JSON?lat=' + latv +
'&lng=' + lngv + '&callback=load JSON';

}

function loadJSON(result ) {
heights.push(re sult.srtm3);

}

function getProfile() {
var dLat = lat[2]-lat[1];
var dLng = lng[2]-lng[1];
for (var i=0; i<d; i+=0.5) {
var latPoints = parseFloat((lat[1] + dLat*i/d)/10);
var lngPoints = parseFloat((lng[1] + dLng*i/d))/10;
getElevationInt er(latPoints,ln gPoints);
}
//alert(i)
if (i>d) {
alert(heights[2])
heightString=he ights.toString( )
alert(heightStr ing)
}

}

Strangely, if I remove the comment // from the alert(i) the script
sometimes works but with the alert(i) commented out it never works.
The alert(heights[2] is there as a test, it is usually undefined
except sometimes when the alert(i) is uncommented when it returns the
correct value.

I would be grateful for any assistance.

Possibly a scope problem with 'heights=[];' ?

[RobG]

On Jun 23, 7:20 am, Steve <stephen.jo...@ googlemail.comw rote:

I am having problems getting values out of an array. The array is set
as a global array and values are pushed into it as they are read from
a JSON file using a "for loop". When the "for loop" is finished I want
to convert the array into a string which can be used by another
function. My attempt to do this is not working. The script looks like
this:

heights=[];

You should always declare variables with var, although that may not be
an issue in this case.

var heights=[];

function getElevationInt er(latv,lngv) {
var script = document.create Element('script ');
document.body.a ppendChild(scri pt);
script.src = 'http://ws.geonames.org/srtm3JSON?lat=' + latv +
'&lng=' + lngv + '&callback=load JSON';

}

function loadJSON(result ) {
heights.push(re sult.srtm3);

}

function getProfile() {
var dLat = lat[2]-lat[1];

What is the result of that? Is it a number? See below.

var dLng = lng[2]-lng[1];
for (var i=0; i<d; i+=0.5) {
var latPoints = parseFloat((lat[1] + dLat*i/d)/10);
var lngPoints = parseFloat((lng[1] + dLng*i/d))/10;

There seems to be a misplaced bracket in the above, -----^

Why have you used parseFloat? What are the values in the lat and lng
arrays? If they are numbers, there is no need for parseFloat. If
they are strings, you need to use parseFloat on the individual values,
e.g.

var latPoints = (parseFloat(lat[1]) + dLat*i/d)/10);

The use of multiplication and division will automatcially convert
dLat, i and d to numbers if they are strings (provided they are
strings that can be converted to numbers, like 23.45).

getElevationInt er(latPoints,ln gPoints);

Here you load the data, but do you wait for the element to become
available?

}
//alert(i)
if (i>d) {
alert(heights[2])
heightString=he ights.toString( )
alert(heightStr ing)
}

}

Strangely, if I remove the comment // from the alert(i) the script
sometimes works but with the alert(i) commented out it never works.
The alert(heights[2] is there as a test, it is usually undefined
except sometimes when the alert(i) is uncommented when it returns the
correct value.

That seems like a timing issue. Are you wating for the script element
to exist before trying to use the content? Try puting the statements
after the alter into a separate function and call it after a delay of
say 1000ms or so (or maybe 2000ms to be sure).
--
Rob

[Steve]

On Jun 23, 3:54 am, Doug Gunnoe <douggun...@gma il.comwrote:

On Jun 22, 4:20 pm, Steve <stephen.jo...@ googlemail.comw rote:

I am having problems getting values out of an array. The array is set
as a global array

Possibly a scope problem with 'heights=[];' ?

The scope of heights=[] is Global.

Steve.

[Steve]

Thanks for the reply but.........

On Jun 23, 5:08 am, RobG <[e-mail] t.auwrote:

>

var dLng = lng[2]-lng[1];
for (var i=0; i<d; i+=0.5) {
var latPoints = parseFloat((lat[1] + dLat*i/d)/10);
var lngPoints = parseFloat((lng[1] + dLng*i/d))/10;

There seems to be a misplaced bracket in the above, -----^

You're right, I'll correct this when I get home tonight.

>
Why have you used parseFloat? What are the values in the lat and lng
arrays? If they are numbers, there is no need for parseFloat. If
they are strings, you need to use parseFloat on the individual values,
e.g.

var latPoints = (parseFloat(lat[1]) + dLat*i/d)/10);

The use of multiplication and division will automatcially convert
dLat, i and d to numbers if they are strings (provided they are
strings that can be converted to numbers, like 23.45).

I used parsefloat because of the problems I was having. I am aware
that is not necessary but it shouldn't matter or cause a problem
should it?

>

getElevationInt er(latPoints,ln gPoints);

Here you load the data, but do you wait for the element to become
available?

}
//alert(i)
if (i>d) {
alert(heights[2])
heightString=he ights.toString( )
alert(heightStr ing)
}
}

Yes, because if I put an alert(heights) in the loadJSON function like
below the result values are displaed in the alert.

function loadJSON(result ) {
heights.push(re sult.srtm3);
alert(heights)
}

Strangely, if I remove the comment // from the alert(i) the script
sometimes works but with the alert(i) commented out it never works.
The alert(heights[2] is there as a test, it is usually undefined
except sometimes when the alert(i) is uncommented when it returns the
correct value.

That seems like a timing issue. Are you wating for the script element
to exist before trying to use the content? Try puting the statements
after the alter into a separate function and call it after a delay of
say 1000ms or so (or maybe 2000ms to be sure).

Maybe, but why should a delay be necessary as I know that the values
are in the array, see above comments on loadJSON.

[RobG]

On Jun 23, 4:58 pm, Steve <stephen.jo...@ googlemail.comw rote:

Thanks for the reply but.........

On Jun 23, 5:08 am, RobG <[e-mail] t.auwrote:

var dLng = lng[2]-lng[1];
for (var i=0; i<d; i+=0.5) {
var latPoints = parseFloat((lat[1] + dLat*i/d)/10);
var lngPoints = parseFloat((lng[1] + dLng*i/d))/10;

There seems to be a misplaced bracket in the above, -----^

You're right, I'll correct this when I get home tonight.

Why have you used parseFloat? What are the values in the lat and lng
arrays? If they are numbers, there is no need for parseFloat. If
they are strings, you need to use parseFloat on the individual values,
e.g.

var latPoints = (parseFloat(lat[1]) + dLat*i/d)/10);

The use of multiplication and division will automatcially convert
dLat, i and d to numbers if they are strings (provided they are
strings that can be converted to numbers, like 23.45).

I used parsefloat because of the problems I was having. I am aware
that is not necessary but it shouldn't matter or cause a problem
should it?

No, I was just seeing if you expect it to do anything that it might
not be doing.

getElevationInt er(latPoints,ln gPoints);

Here you load the data, but do you wait for the element to become
available?

}
//alert(i)
if (i>d) {
alert(heights[2])
heightString=he ights.toString( )
alert(heightStr ing)
}
}

Yes, because if I put an alert(heights) in the loadJSON function like
below the result values are displaed in the alert.

function loadJSON(result ) {
heights.push(re sult.srtm3);
alert(heights)

}

The code you posted doesn't call loadJSON, it is included in the URI
for the script element's src attribute. Where do you call it from?

Strangely, if I remove the comment // from the alert(i) the script
sometimes works but with the alert(i) commented out it never works.
The alert(heights[2] is there as a test, it is usually undefined
except sometimes when the alert(i) is uncommented when it returns the
correct value.

That seems like a timing issue. Are you wating for the script element
to exist before trying to use the content? Try puting the statements
after the alter into a separate function and call it after a delay of
say 1000ms or so (or maybe 2000ms to be sure).

Maybe, but why should a delay be necessary as I know that the values
are in the array, see above comments on loadJSON.

Did you try it?

The reason I think it might be an issue is that after you assign a
value to the DOM element's src property, the function moves on. I
don't think there is anything that says it should wait until the
script file has actually finished loading and code executed before
moving to the next step in the function.
--
Rob

[Steve]

On Jun 23, 9:11 am, RobG <[e-mail] t.auwrote:

On Jun 23, 4:58 pm, Steve <stephen.jo...@ googlemail.comw rote:

Thanks for the reply but.........

On Jun 23, 5:08 am, RobG <[e-mail] t.auwrote:

var dLng = lng[2]-lng[1];
for (var i=0; i<d; i+=0.5) {
var latPoints = parseFloat((lat[1] + dLat*i/d)/10);
var lngPoints = parseFloat((lng[1] + dLng*i/d))/10;

There seems to be a misplaced bracket in the above, -----^

You're right, I'll correct this when I get home tonight.

Why have you used parseFloat? What are the values in the lat and lng
arrays? If they are numbers, there is no need for parseFloat. If
they are strings, you need to use parseFloat on the individual values,
e.g.

var latPoints = (parseFloat(lat[1]) + dLat*i/d)/10);

The use of multiplication and division will automatcially convert
dLat, i and d to numbers if they are strings (provided they are
strings that can be converted to numbers, like 23.45).

I used parsefloat because of the problems I was having. I am aware
that is not necessary but it shouldn't matter or cause a problem
should it?

No, I was just seeing if you expect it to do anything that it might
not be doing.

getElevationInt er(latPoints,ln gPoints);

Here you load the data, but do you wait for the element to become
available?

}
//alert(i)
if (i>d) {
alert(heights[2])
heightString=he ights.toString( )
alert(heightStr ing)
}
}

Yes, because if I put an alert(heights) in the loadJSON function like
below the result values are displaed in the alert.

function loadJSON(result ) {
heights.push(re sult.srtm3);
alert(heights)

}

The code you posted doesn't call loadJSON, it is included in the URI
for the script element's src attribute. Where do you call it from?

Strangely, if I remove the comment // from the alert(i) the script
sometimes works but with the alert(i) commented out it never works.
The alert(heights[2] is there as a test, it is usually undefined
except sometimes when the alert(i) is uncommented when it returns the
correct value.

That seems like a timing issue. Are you wating for the script element
to exist before trying to use the content? Try puting the statements
after the alter into a separate function and call it after a delay of
say 1000ms or so (or maybe 2000ms to be sure).

Maybe, but why should a delay be necessary as I know that the values
are in the array, see above comments on loadJSON.

Did you try it?

The reason I think it might be an issue is that after you assign a
value to the DOM element's src property, the function moves on. I
don't think there is anything that says it should wait until the
script file has actually finished loading and code executed before
moving to the next step in the function.

--
Rob

Hi Rob,

I will try it this evening and let you know what happens.

Thanks for your help.

Steve.

[Doug Gunnoe]

On Jun 23, 1:45*am, Steve <stephen.jo...@ googlemail.comw rote:

On Jun 23, 3:54 am, Doug Gunnoe <douggun...@gma il.comwrote:

On Jun 22, 4:20 pm, Steve <stephen.jo...@ googlemail.comw rote:

I am having problems getting values out of an array. The array is set
as a global array

Possibly a scope problem with 'heights=[];' ?

The scope of heights=[] is Global.

Steve.

Yes I know.

My first inclination was that there could have been some issues
regarding this.

from http://developer.mozilla.org/en/docs...Statements:var
--
Using var outside a function is optional; assigning a value to an
undeclared variable implicitly declares it as a global variable.
However, it is recommended to always use var, and it is necessary
within functions in the following situations:

* If a variable in a scope containing the function (including the
global scope) has the same name.
* If recursive or multiple functions use variables with the same
name and intend those variables to be local.

Failure to declare the variable in these cases will very likely lead
to unexpected results.
--

But, after testing the idea out for a little while I decided that this
probably wasn't the problem.

I am intrigued by RobG's thought that this could be a timing problem.
And I too would like to know at what point you are calling functions
in the the script you insert into the DOM tree.

Good luck with this. Sorry I wasn't any help.

[Laser Lips]

I remember having this problem when trying to use google maps. I'm
raking my brains to remeber what the soloution was