Create a point-density heatmap from CSV

Upload a header-based CSV and select one latitude and one longitude column. The parser skips empty rows but otherwise reads the available data in the browser.

• Recognized latitude names include lat and names containing latitude
• Recognized longitude names include lng, lon, and names containing longitude
• You can override the automatically selected columns

The current filter checks only whether JavaScript converts each selected value to a finite number. It does not enforce geographic ranges.

• Remove blank coordinate cells because an empty string can convert to zero
• Require latitude from -90 to 90 and longitude from -180 to 180 in the source
• Remove headers, units, or symbols from coordinate cells
• Watch for accidental points near 0,0 caused by blank or malformed data

Each accepted row contributes one equally weighted point. Color intensity reflects nearby point density in the built-in map style.

• There is no weight or value column
• There are no radius, intensity, blur, threshold, or palette controls
• The layer is for visual exploration, not a statistical density estimate

Use a heatmap to notice broad concentrations. Use a marker map when visitors need exact locations, counts, labels, popups, filters, or actions.

• Dense patterns can hide data quality errors
• Zoom changes the visible intensity pattern
• Compare hotspots with the cleaned source before drawing conclusions

CSV parsing and point preparation happen in the browser, while normal basemap resources load over the network. This helper does not save, export, or publish the heatmap.

• There is no verified maximum-row performance claim
• Large files can be limited by the user's device and browser
• Use the full editor only after confirming that its current heatmap and plan capabilities fit the project