Steps for assigning each element in the array to a separate variable

Question

Steps for assigning each element in the array to a separate variable

My array is dynamic and the length varies, but it looks like this:

var coord_list = [[-7.84 , 12.32],[-8.30 , 10.42],[-11.84 , 12.32]....]

I am trying to incorporate each element (coordinates) "[-7.84 , 12.32]" into a turf module which is done like this:

turf.lineString([[-7.42,9.125],[-8.43,9.800]]...(all of them), {name: 'line 2'});

.

When attempting to use the var coord_list array directly, I encountered issues despite it having the same structure internally.

turf.lineString([coord_list], {name: 'line 2'}); --> Error: coordinates must be an array of two or more positions
turf.lineString(coord_list, {name: 'line 2'}); --> Error: coordinates must contain numbers

How can I properly integrate each coordinate into the turf formula?

javascript arrays coordinates

Answer 1

Answer №1

As per the guidelines provided in the turf documentation, an illustration of the syntax would be:

var linestring1 = turf.lineString([[-24, 63], [-23, 60], [-25, 65], [-20, 69]], {name: 'line 1'});

The primary argument consists of an array of positions.

Hence, your second line appears to be accurate:

var coord_list = [[-7.84 , 12.32],[-8.30 , 10.42],[-11.84 , 12.32]....] // is an array of positions
turf.lineString(coord_list, {name: 'line 2'}); --> Throws an Error: coordinates must contain numbers

The error suggests that the dynamically generated coord_list contains strings instead of numbers.

To verify this, you can output the typeof each position value.

In order to convert each value into a number, you need to pass the x,y value of each position through:

let xNum = parseFloat(x);
let yNum = parseFloat(y);

prior to supplying them to

turf.lineString([[xNum, yNum],[xNum2, yNum2],...],{name: 'line 2'})

If there is no control over how coord_list is generated, it can be rectified as follows:

let arr = [['-7.84' , '12.32'],['-8.30' , '10.42'],['-11.84' , '12.32']];

let coord_list = arr.map(position => {
    return [parseFloat(position[0]), parseFloat(position[1])];
})

Answer 2

As per the guidelines provided in the turf documentation, an illustration of the syntax would be:

var linestring1 = turf.lineString([[-24, 63], [-23, 60], [-25, 65], [-20, 69]], {name: 'line 1'});

The primary argument consists of an array of positions.

Hence, your second line appears to be accurate:

var coord_list = [[-7.84 , 12.32],[-8.30 , 10.42],[-11.84 , 12.32]....] // is an array of positions
turf.lineString(coord_list, {name: 'line 2'}); --> Throws an Error: coordinates must contain numbers

The error suggests that the dynamically generated coord_list contains strings instead of numbers.

To verify this, you can output the typeof each position value.

In order to convert each value into a number, you need to pass the x,y value of each position through:

let xNum = parseFloat(x);
let yNum = parseFloat(y);

prior to supplying them to

turf.lineString([[xNum, yNum],[xNum2, yNum2],...],{name: 'line 2'})

If there is no control over how coord_list is generated, it can be rectified as follows:

let arr = [['-7.84' , '12.32'],['-8.30' , '10.42'],['-11.84' , '12.32']];

let coord_list = arr.map(position => {
    return [parseFloat(position[0]), parseFloat(position[1])];
})

Answer 3

Answer №2

Based on your recent revision highlighting the mistakes, it seems like your coordinates may be mistakenly included as strings instead of numerical values while forming the coord_list.

Answer 4

Based on your recent revision highlighting the mistakes, it seems like your coordinates may be mistakenly included as strings instead of numerical values while forming the coord_list.

Steps for assigning each element in the array to a separate variable

Answer №1

Answer №2

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