Spike Maps

Learn how to visualize data patterns across geographic locations using spike maps.

Overview

Spike Maps display data from a spike field on defined points of latitude and longitude. Each spike can be assigned both color and height dimensions, with the option to display negative values as downward-facing spikes. These maps allow users to visualize intensity or magnitude across a defined geographic area, helping to revealing spatial patterns or trends at a glance.

Spike maps are commonly used in fields like environmental monitoring, economics, and risk analysis to depict data such as pollution levels, population density, or economic output across regions. They are also valuable in political forecasting and election analysis, as the spikes can represent changes in variables like voter turnout and party support.

Setup

After inserting a map, navigate to the Map tab in the right panel. In the Setup section, you can assign basic properties to the map, which are detailed on the Maps overview page. Next, open the Map Type section and click on Spike Map.

Connecting to a Basemap

In the Basemap section under the Map tab, you can select an underlying basemap for your map element. The basemap is a map, stored in GeoJSON format, consisting of features (geographical shapes) such as countries, provinces, and electoral districts. In order to add a basemap to a map element, you must first add a basemap to your project. This can be done by selecting New Basemap in the Project tab. Clicking Find Basemap then opens a library of more than 600 basemaps to choose from.

MAPPICA Pro

If you are on the Pro plan, you can upload your own files (in GeoJSON format) to use as basemaps, by clicking New Basemap, then Upload Basemap.

In spike maps, the basemap serves as a background layer, defining the geographic extent of the map container. While the basemap itself is not connected to the overlaid spikes, it establishes the visible area in which the spikes are displayed.

Connecting to Datasets

In the Dataset section under the Map tab, you can select the dataset for your map element, which contains the data that you wish to display on the map. In order to add a dataset to a map element, you must first add a dataset to your project. This can be done by selecting New Dataset in the Project tab.

MAPPICA Pro

If you are on the Pro plan, you can upload your own files (in csv format) to use as datasets, by clicking New Dataset and then Upload Dataset.

After you have selected a dataset, you can optionally enable the Prefilter Dataset switch, which lets you filter the data that is supplied to the map. The filter is a "prefilter" because it is applied before the visualization is generated; end users are unable to adjust the filter dynamically.

You can also enable the Connect to Filter switch, which allows your end user to filter the map data in real-time using one or more filter elements on the canvas.

Next, select Latitude and Longitude fields. These are fields (columns) within the selected dataset that will determine the location of each spike on the map element. Both fields must be assigned the Coordinate data type in the dataset editor

Connecting to Filters

You can establish connections to filter elements under the Map tab, in the Connections section, by making a selection under Filter.

Filter elements display values from a specified Filter Field, in the form of checkboxes, dropdown menu items, or (for numeric filtering) slider values. A given map can be connected to one or more filters, and the same filter can be connected to multiple maps or other elements. Once connected to a map, a filter element will dynamically control the dataset records passed to the map element, based on user selections made on the filter.

For more details about connecting to filters, see the main Maps page.

Colors

In the Colors section under the Map tab, you can assign a Color Field from the selected dataset. Choose either a text or numeric field (e.g., number, currency, percent, or measurement). For text fields, each unique value becomes a category that can be assigned a specific color. For numeric fields, you can configure a Color Gradient, set Domain Minimum and Maximum values, and define the Color Scale. Additionally, you can assign a Missing Data Color and adjust the default Opacity. For more details, see our Colors page.

You can also assign a fixed color to all spikes on the map. This is useful when you only want to vary the spike height while keeping the color consistent.

Spikes

In the Spikes section under the Map tab, you can adjust certain properties related to the size and appearance of the spikes:

Spike Height: The Spike Height Field controls the height of spikes based on the values it contains. The Maximum Spike Height field sets the spike's height when the value in the Spike Height Field reaches the Maximum Spike Value. Other values are scaled proportionally. If Maximum Spike Value is set to "auto," it defaults to the largest value in the Symbol Size Field.
Border: You can specify a Border Width for all spikes on the map. By default, the border shares the same color as the spike, making it blend in unless the spike's Opacity, set in the Colors menu, is reduced below 100%. Alternatively, you can apply a Custom Border Color, which assigns the same border color to all spikes, regardless of their inner fill color.

Annotations

In the Annotations section under the Map tab, you can add annotations consisting of text and/or symbols to your map.

Begin by picking a longitude and latitude to place the annotation on the map. You can then choose either or both of the following two options:

Add Text: Add some Text, pick a Color, and specify the Text Position in relation to the chosen longitude and latitude.
Add Symbol: Choose a Symbol Shape, a Color for the symbol, and a fixed Width in pixels.

Tooltips

Tooltips on maps can be enabled by selecting the Map tab, navigating to the Tooltip section, and selecting Display Tooltip. These are automatically configured to display the series fields you have selected in your map.

In situations where the same field has been used more than once (for instance if you are using the same field to set both spike height and color), the tooltip will only display information about the field once.

Overview
Setup
Connecting to a Basemap
Connecting to Datasets
Connecting to Filters
Colors
Spikes
Annotations
Tooltips