Privacy policy
ContourMapMaker works without an account. Contours are computed in your browser, and we collect as little as we can.
The free tool runs in your browser
Elevation data is downloaded by your browser and the contour lines are computed there, in a Web Worker. Free downloads (PNG, GeoJSON, SVG and KML) are made in your browser too. We do not receive or store the areas you look at or the maps you make.
Boundary files you import (KML or GeoJSON) are read in your browser and never uploaded. The tool checks their type, size (up to 5 MB) and contents locally and keeps only the outline in memory while the page is open.
Saved areas are kept in your browser's local storage on your device; we never see them, and clearing your site data removes them. Share links put the area and settings in the part of the address after #, which browsers do not send to our server.
Services your browser contacts
To draw the map, your browser fetches data directly from these public services. Like any website, they receive your IP address and the request; their own privacy policies apply.
| Service | Used for | What it sees |
|---|---|---|
| Terrain Tiles on AWS (s3.amazonaws.com) | Elevation tiles for the area on the map | The tile addresses, which reveal the map area |
| USGS National Map (elevation.nationalmap.gov) | Pro only: 1 m lidar for US areas | The area requested |
| OpenStreetMap tile servers (tile.openstreetmap.org) | The street basemap, when it is on | The map tiles you view |
| Overpass API (overpass-api.de) | Roads and buildings, only when you turn them on | The area requested |
| Nominatim (nominatim.openstreetmap.org) | Place search | The text you search for |
Pro files
When you download a Pro file (DXF, layered SVG, KMZ, Shapefile, 8000 px PNG or a batch), your browser sends the contour lines on your map and your export settings to our server. The server builds the file in memory and sends it back. We do not store the lines, the file or the area, and we do not log their contents. To stop abuse, the server counts requests per visitor for a short time window using a one-way keyed hash of the IP address, not the address itself; the counts expire after the window.
Payments
Payments are handled by Stripe, which receives your payment details and email address. We receive a payment confirmation and an anonymous customer reference. We never see your card number.
What we store
To remember what you paid for, we store an anonymous access record (plan, status, expiry) and a one-way keyed hash of the email address you paid with, so you can sign in on another device. We cannot turn that hash back into your email address. Sign-in emails are sent through our email provider.
The free tool sets no cookies. When you buy a plan or sign in, we set a single strictly necessary cookie that keeps your access on this browser. It holds only the anonymous access reference, is signed so it cannot be forged, and cannot be read by scripts.
Analytics
We use Plausible Analytics, which does not use cookies and does not collect personal data. It counts page views and a few anonymous events, such as starting the tool, generating contours and which export format was downloaded. Events may include the size of the area in km², the interval and the data source, never the location you mapped.
Your choices
Email contourmapmaker@vezli.net to delete your access record or to ask any question about this policy. See also the terms of use, or go back to the contour map tool.