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I cannot figure out how to use the torque map:

A typical row of my data, which is named torquedata3, looks like : [nodenumber, lat,long,time,value].

I have multiple rows at the same time with each row having a different "value" ranging from 0-7. I simply want to display at each different node a different color depending on the value.

Sorry for how easy my question may seem but I can not get it to work, I have tried all sorts of different torque-aggregation-functions(avg, round(avg()), min, max, count).

Below is the code I am using (field 4 has the time and field_5 has my values I want to display).

/** torque visualization */

Map {
-torque-frame-count:30;

-torque-animation-duration:60;

-torque-time-attribute:"field_4";

-torque-aggregation-function:"count(field_5)";

-torque-resolution:1;

-torque-data-aggregation:linear;
}


torquedata3{
  marker-width: 4;

  [value = 0] { marker-fill: #229A00; }

  [value = 1] { marker-fill: #0F3B82; }

  [value = 2] { marker-fill: #7B00B4; }

  [value = 3] { marker-fill: #000000; }

  [value = 4] { marker-fill: #FF2900; }

  [value = 5] { marker-fill: #CC4C02; }

  [value = 6] { marker-fill: #993404; }

  [value = 7] { marker-fill: #662506; }

}

I am now trying to create a heatmap.

I have changed some of the commands to

Map {
-torque-frame-count:30;
-torque-animation-duration:90;
-torque-time-attribute:"field_4";
-torque-aggregation-function:"sum(field_5)";
-torque-resolution:1;
-torque-data-aggregation:linear;
}

#torquedata3{
  image-filters: colorize-alpha(red); 
  marker-file: url(http://s3.amazonaws.com/com.cartodb.assets.static/alphamarker.png);
 marker-fill-opacity:0.5*[value];
 marker-width: 5;

But I cannot do this multiplication on the value, I get the error message: Invalid value for marker-fill-opacity, the type float is expected. 0.5*[value](of type field) was given. I would like to use the marker file that fades in order to get a heat map type visual as opposed to the dots that do not fade into each other as much.

  • Hi there, welcome to GIS stack exchange. I formatted your code using the CODE tag for easier readability. – Stephen Lead Jul 14 '16 at 4:17
1

I have replicated your dataset according to your description (I highly recommend next time give us the link anyway). Here is my dataset, called new_table. It contains the following columns: cartodb_id(numeric), the_geom(geometry/points), city(string) and country(string), order_num(numeric, this should be your field_4) and colors(numeric, and this should be as field_5).

If you select Torque Map in CARTO Wizard and change the CartoCSS a little bit in order to add the colors, you end up with a block of CartoCSS code like this:

/** torque visualization */

Map {
-torque-frame-count:256;
-torque-animation-duration:30;
-torque-time-attribute:"order_num";
-torque-aggregation-function:"sum(colors)";
-torque-resolution:2;
-torque-data-aggregation:linear;
}

#new_table{
  comp-op: lighter;
  marker-fill-opacity: 0.9;
  marker-line-color: #FFF;
  marker-line-width: 0;
  marker-line-opacity: 1;
  marker-type: ellipse;
  marker-width: 6;
  marker-fill: #0F3B82;
}
#new_table[frame-offset=1] {
 marker-width:8;
 marker-fill-opacity:0.45; 
}
#new_table[frame-offset=2] {
 marker-width:10;
 marker-fill-opacity:0.225; 
}

#new_table{
  [value = 1] { marker-fill: #FFCC00; }

  [value = 2] { marker-fill: #FFA300; }

  [value = 3] { marker-fill: #FF5C00; }

  [value = 4] { marker-fill: #FF6600; }

  [value = 5] { marker-fill: #FF2900; }

  [value = 6] { marker-fill: #F11810; }

  [value = 7] { marker-fill: #B40903; }

}

I have reused the code from this gist (where I also add a bubble effect), and this is the resulting map.

Take good care to set torque-time-attribute parameter to your date or numeric field that you want your data-points to be ordered. In addition, you should set torque-aggregation-function attribute to other aggregation operation but count. What Torque.js is doing is aggregating in a third dimension (usually time) and apply that formula. So if you use count with just 7 rows with different values, you will end up with value equal to 1 each time/bin.

  • Thank you that seemed to work. I also read somewhere that [value = 0] does not work, is this true? Some of the elements in my field_5 are valued 0. – Michael Jul 14 '16 at 16:33
  • The value 0 does not work with count aggregation function, because you always get more than one figure. Last, if your question has been answered, please set as answered. – ramiroaznar Jul 14 '16 at 16:45

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