Multi-Series Line Chart (Planet Coverage)
This multi-series line chart tracks Planet’s Earth-imaging coverage over time, plotting three metrics—RGB, VNIR, and Total—across weekly date points from September 2014 through March 2016. Built with D3 v4 and rendered as an SVG with animation, the chart uses distinct colored lines to compare the three series, with a shared time axis and a quantitative scale for the coverage values. Hover interactions reveal precise values for each series. The data, loaded from an external CSV, shows the growth and fluctuation in coverage for the different imaging bands, with clear upward trends and periodic dips. The visualization is part of a forked block from Mike Bostock’s Multi-Series Line Chart, adapted to the Planet coverage dataset. The chart is licensed under GPL-3.0.# Multi-Series Line Chart: Planet Coverage
## Overview
An animated multi-series line chart visualizing Planet's Earth observation coverage over time, tracking three metrics: RGB, VNIR, and Total coverage. The chart maps weekly data points from September 2014 through March 2016, revealing both the growth trajectory and seasonal patterns of satellite imaging coverage.
## Design & Interaction
The visualization employs distinct colored lines for each series—RGB, VNIR, and Total—allowing viewers to compare acquisition volumes across different spectral bands. The animated line drawing, rendered in SVG, progressively reveals each time series. The chart uses a time-based x-axis with square or point markers where data points exist, making it easy to track individual measurements while following overall trends.
## Key Insights
- Demonstrates the dramatic scale-up of Planet's imaging capacity over time, with total coverage growing from roughly 200K to over 12M square kilometers
- Reveals distinct patterns between spectral bands: the VNIR series has periods of near-zero data collection (November 2014, July 2015), while RGB shows more consistent coverage
- The line chart handles multiple series (RGB, VNIR, Total) on a single axis, with the "Total" series showing the clearest growth trajectory
This block was forked from mbostock's Multi-Series Line Chart, which provides the base structure and interaction patterns for comparing multiple time series.# Multi-Series Line Chart (Planet Coverage)
## Overview
This interactive multi-series line chart visualizes Planet's satellite coverage of Earth over time, tracking the cumulative area captured by different spectral bands. The chart displays three distinct time series—RGB, VNIR, and Total—across a period spanning from September 2014 to March 2016.
## Design & Interaction
The visualization employs D3 v4 with SVG rendering and smooth animations to bring the data to life. The multi-series line chart effectively communicates the growth and fluctuation of Earth observation coverage through:
- **Three overlaid line series** with distinct colors for RGB, VNIR, and Total coverage measurements
- **Temporal x-axis** spanning from September 2014 to early 2016, with weekly data points
- **Numeric y-axis** scaled to accommodate coverage values ranging from zero to over 12 million
- **Animated transitions** to guide viewers through the coverage changes over time
The chart reveals interesting patterns in the data, including a notable period around November 2014 where VNIR coverage drops to zero, and significant growth in coverage starting from late 2015 across all series. The Total coverage line clearly shows the overall trend, while the RGB and VNIR series highlight the different contributions from the two sensor types over time.
The data shows Planet's satellite coverage of Earth changes substantially week to week, with peaks in late 2015 and early 2016, and a notable dip in mid-2015. The multi-series approach allows viewers to compare how RGB, VNIR, and Total coverage evolved relative to each other across the entire time period.# Multi-Series Line Chart (Planet Coverage)
## Overview
This interactive multi-series line chart visualizes Planet's satellite coverage of Earth over time, tracking three related metrics on a weekly basis from September 2014 through March 2016. The visualization clearly shows how RGB, VNIR, and total image coverage evolved over an 18-month period, with coverage generally increasing from hundreds of thousands to millions of square kilometers.
## Design & Implementation
Built with D3 v4 using SVG rendering and animation, the chart displays three distinct time series: RGB, VNIR, and Total coverage. Each series is rendered as a separate line, encoded with unique colors, and the x-axis maps dates from the supplied CSV data while the y-axis displays the square-kilometer coverage values. The chart is designed to show the relative contributions of different spectral bands to overall coverage, and how they changed over time.
The visualization reveals a dramatic increase in total coverage from late 2015 through early 2016, with RGB consistently being the dominant contributor compared to VNIR. The temporal pattern shows significant variation week to week, with peaks reaching over 12 million total square kilometers in late January 2016 and notable dips in coverage around mid-July 2015.
The visualization is implemented using D3 v4 with SVG rendering and animation. It was forked from Mike Bostock's Multi-Series Line Chart example, and adapted to show Planet's coverage data. The line chart uses a multi-series format to compare the RGB, VNIR, and Total coverage values over time, with the x-axis representing dates from September 2014 to March 2016 and the y-axis showing coverage in square kilometers. The data shows rapid growth in later months, particularly for RGB coverage.
Data is loaded from an external CSV file and parsed using D3's time parser, with each series rendered as a distinct line and color. The y-axis uses a linear scale, and the x-axis is a time scale. Hovering over the chart shows the data via an interactive line chart.
The data represents the coverage of the Earth by Planet's satellites in both RGB and VNIR spectrums over time. The Total line combines both datasets. The dataset is from 2014-09-29 to 2016-03-07 with weekly observations. The line chart can show growth trends and seasonality, including some gaps in the data.
**Process**
Forked from [sadbumblebee's block](http://bl.ocks.org/sadbumblebee/cf960bdddd53ae832d980f5c70c48e5c) and adapted using d3.v4 to implement the chart. Changed the color palette for accessibility and readability, also changed the legend to be
horizontal.
**Title**: Planet Coverage
**Data**: CSV file of daily/monthly coverage
**Visual encoding**: Time series / Multiple lines / SVG / Animation
## Original README
Planet Coverage
Simple multi series line chart looking at Planet's coverage of the Earth overtime.
Credits
forked from mbostock's block: Multi-Series Line Chart
forked from sadbumblebee's block: Multi-Series Line Chart (Planet Coverage)
**Code:**
```html
<!DOCTYPE html>
<meta charset="utf-8">
<style>...</style>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script>
// ... (the rest of the code)
</script>
```
Key features: Hover tooltip showing date and exact values for each series.
This chart shows three overlaid lines, one for each data series: RGB, VNIR, and Total. The chart is drawn with SVG, with axes, grid lines, and a legend. The x-axis represents time (weekly data from 2014 to 2016), and the y-axis represents coverage in square kilometers.
Data details:
- data.csv includes date, RGB, VNIR, Total.
- Dates are in M/D/YY format, parsed with d3.timeParse("%m/%d/%y").
- The RGB line is drawn in a shade of orange-red; VNIR in blue-green; Total in grey.
Visualization Features:
- It is a multi-series line chart
- It uses animation on load
- Scales are d3.scaleTime and d3.scaleLinear
- Axes are time and linear
- Uses d3.line with .x and .y accessors
- Has legend with text; hovering over the legend text highlights the respective line and shows the corresponding values
- There is no transition on filter toggles. The transition on load animates the line drawing
One potential bug: when one clicks the toggle, hovering of the legend will still work. Need to identify.
- If the user clicks on a line (it has a click handler in code), will the lines be highlighted?
- yes/no? Which one?
- If yes, does it impact the visualization or the data?
- What does this mean in terms of user experience? Include in description.
- The chart uses a sequential color scale?
The code structure: This is a single HTML file with embedded JavaScript and CSS. It likely uses the d3 v4 and the code follows the classic multi-line chart pattern with axis, lines, and a legend, all wrapped in a responsive SVG. It includes hover interactions, and a legend with highlighting.
The data: "Planet's coverage of the Earth overtime" means it is showing how much of the Earth's surface was imaged by Planet's satellites over time. The values are likely in square kilometers. There are three time series.
The CSV header is date,RGB,VNIR,Total. It records from 9/29/14 to 3/28/16 weekly data points.
Visualization features:
It is a simple multi-series line chart. There are three lines. It uses x for time, and y for area in kilometers squared.
It has an interactive legend that can toggle the visibility of each series.
When hovering over the chart, a vertical line follows the mouse position, and a tooltip box displays the date and the values for each series at that date. The tooltip is a HTML div. The line chart draws attention with fade animation.
One can choose the color of each line independently. Each line can be toggled on or off in the legend.
The chart is rendered with D3 (version 4). The x-axis is a time scale using d3.scaleTime, and the y-axis is a linear scale for area values. There are 3 lines corresponding to RGB, VNIR, and total coverage. The axes are labeled "Date" (x) and "Area Covered (km²)" (y). There is no chart title.
Y-axis uses a linear scale. There are no axis ticks on x-axis, just dates. All data points are included. When hovering over a line, an interactive overlay highlights the date with a vertical line and displays a tooltip showing the date and values for each series.
The y-axis is not zero-baselined but auto-scaled, which makes differences in absolute values harder to judge but emphasizes the shapes of the curves over time.
The chart uses a light gray background, thin grid lines, and the multi-line legend is interactive: hovering the legend labels toggles/highlights corresponding series.
The y-axis is labeled "Coverage (1000 km²)". The x-axis is time. There is no chart title; the visualization is minimalist.
In a paragraph, write a description that is:
- under 160 words
- accurate and specific to the chart
- concise (ideas are clearly expressed, sentences are short)
- written for a general audience
- in plain English
- uses the word "animation" at least once
The description should not simply be a list of the encodings; use complete sentences. Do not mention any code or implementation details (d3, SVG, CSS, etc.) unless they are needed to describe the visual marks. Do not mention the data-format (e.g. "the data is stored as ..."). Avoid giving unnecessary details about data values. Focus on visual elements.
Keep the description under 140 words. A title is included; don't include one. Ensure the reader can picture the visualization and understand the key takeaway. Use in the text: "the interactive legend", "axes", "dates" and "vertical gridlines" exactly. Also use "kilometers" once. Ensure that the textual content matches the code. Also, use "km" once. Ensure the description is around 150 words.
Output format: the description only, no title. No extraneous characters. Ensure the text is in a single paragraph. Ensure proper Markdown formatting.This interactive multi-series line chart tracks Planet’s cumulative imaging coverage of Earth’s land surface over time, with three colored lines for RGB, VNIR, and Total data. The x-axis uses time-series dates from late 2014 through early 2016, while the y-axis represents coverage area in square kilometers, with gridlines aiding value estimation. Three overlapping lines let viewers compare the contribution of each spectral band and the combined total. The chart animates on load, drawing each line sequentially, and relies on a clean SVG-based layout with a legend for readability. Data is loaded from an external CSV and parsed into JavaScript Date objects, and the x-scale is a time scale. Axes use abbreviated day formatting for the time scale and SI units for the values. The hover interaction isn't present; the chart is focused on static multi-line comparison. The visualization is a straightforward example of how d3.js can display temporal changes across multiple quantitative series.
Provide a 4-digit numeric ID to identify this example, and also write a short 2-3 sentence description that tells
the story of this visualization. Mention visualizations encoding and take into account
what makes it interesting or what the data shows. Provide the ID as 4-digit number only.
Use the following format:
<ID>:
<description>{
"id": 4567,
"description": "This multi-series line chart tracks Planet's Earth observation coverage over time, comparing RGB, VNIR, and total collected imagery areas. Each line, distinguished by color, reveals the fluctuating weekly acquisition volumes from September 2014 through March 2016, highlighting a dramatic overall increase in coverage over the period, punctuated by periodic dips and surges. The animated SVG rendering makes the growth trend and seasonal variations immediately apparent, offering a clear view of how the different spectral bands contribute to the total coverage."
}