Help - Mendip Cave Map

This Mendip Cave Map is based on the most recent version of my Where's The Path site which will be found here. This Mendip Cave Map adds markers for Mendip caves and selected cave survey overlays. Normal caves are shown with a red pin red and caves tagged as a 'Dig' by CSCC with a yellow pin yellow .

The Cave Access data used is from the CSCC and was last fetched in September 2025. To obtain the best cave locations, the CSCC data has been cross-referenced with MCRA data.

The Mendip Cave Map is intended for general reference only. It is not a definitive guide to cave locations or access. Please refer to the CSCC Access Guide and MCRA Registry for up to date authoritative information.

Please be aware that Cookies are used to preserve the state of the map display etc between visits. Some special features are used to improve the way the site works on a Tablet.

The display of modern Ordnance Survey mapping from OS Data Hub has a monthly limit. So please remember that if you use OS mapping full screen on a big display, you may well cause someone else mapping disappointment later in the month.

How to use the site

Navigate the maps in the normal way with mouse drag and scroll-wheel zoom - or pinch zoom on a tablet. Double click and double tap will do a zoom in. As you move the mouse pointer over one map, or tap a Tablet with your finger, its position is shown on the other - as a blue arrow. If the zoom levels of the two maps are different, the coverage of one map is shown on the other as a blue box.

The controls have been grouped together on Tabs to save space, especially when using a Tablet.

The first Tab contains controls for the left, top or only map:

A selector for the Base Layer
A selector for an Overlay Layer
A selector for a Grid / Graticule - No Grid, a Lat/Lon Grid, a UK OS Grid or a fixed interval UK Grid
A button to press for this Help

The second Tab contains controls for the right or bottom map:

A selector for the Base Layer - use 'Hide' to select a single map display
A selector for an Overlay Layer
A selector for a Grid / Graticule - No Grid, a Lat/Lon Grid, a UK OS Grid or a fixed interval UK Grid
A check box for linking the zoom level of the two maps together

If an Overlay is selected for either map, re-click the Tab to switch left-right mouse/finger drag, between adjusting the blend of the two map layers and panning of the map.

The following map base layers are available:

Map Google Map
Satellite Google Satellite
Hybrid Google Hybrid
Terrain Google Terrain or Physical, includes hill shading and some paths
OS Modern Ordnance Survey via OpenSpace including 1:25,000 and Streetview
OSM Open Street Map
Old 25K OS Old Ordnance Survey 1:25,000 from the National Library of Scotland
Historical OS Old Ordnance Survey mapping from the National Library of Scotland
Caves Selected Mendip Cave Surveys
Rakes A detailed map of the Charterhouse Rakes
SSSI Sites of Special Scientific Interest in the Mendip area
C Terrain Colour Terrain data for the Mendip area
BW Terrain Monochrome Terrain data for the Mendip area
Bedrock Bedrock mapping from the British Geological Survey - use right click to query for bedrock type
Deposits Deposit mapping from the British Geological Survey - use right click to query for deposit type
Linear Linear Feature mapping from the British Geological Survey

The site uses some bespoke, in browser, technology to warp the modern OS mapping to the same projection used by all the other map layers. Only by this means, is it possible to overlay for example Old and Modern OS mapping or OS mapping and Google imagery.

Google Streetview is available on the left or right map by dragging the Google pegman onto the map.

The third Tab contains controls for:

Displaying coordinates. Re-click the Tab or double click the text box to select the desired format. To freeze the displayed location and show its altitude, click or touch on either map. The location text may then be copied. To have the text track the pointer again, click or touch on the map. To change the altitude units, double-click the altitude text.
Placing Waypoints. Press the button, then click on either map. Click on the Waypoint marker to give it a name and description (for later export).
Clearing Waypoints.
Getting a link to the page as currently displayed (Base Layers, Overlays, Zooms and Centre). To have a GPX file load automatically use a final URL parameter of gpx=myGpxUrl, preceeded by wpt=1 if you want the GPX load to show waypoints in addition to any Tracks or Routes.

The fourth Tab contains controls for:

Entering text for a location to pan to or a name to search for. Parsing is done in the following order:
- UK Grid ref e.g. "SU 800 600" with or without spaces
- Two numbers separated by a space or comma are taken as a Latitude and Longitude pair
- Text with a comma, e.g. a postal address, is submitted to Google Maps search.
- If there are digits in the text, then a Postcode search is made.
- Anything else is submitted to the Ordnance Survey Gazetteer. Search text can be for a hill, lake, river, village etc.
Perform the search for the entered text. If more than one result is found then a selector is presented for you to choose the wanted result. If there is only one result, or a choice is made, then the maps are panned to the result and the pointer is set to point at the result. The pointers are frozen, until the map is clicked or touched.
Panning the maps to the current location provided by your browser.

The fifth Tab contains controls for building, importing, exporting, profiling and printing routes and waypoints:

To construct a route simply click points on either map. If you are using a Tablet, use the side buttons to switch between panning the map and marking route points. On a Tablet, an offset pointer is used and points are placed when your finger is lifted. You may go back and move points around or insert points into a 'Leg' (not easy on a Tablet). You can use a right click to delete a node on a Leg. When Printing, each 'Leg' is shown as one row of a 'Route Card'. If the OSM Cycle map is used, then Open Cycle routing is used to between the start or end of you route and the click point. The start of your route is shown with a Green Circle marker, the start of each intermediate Leg with a Blue Circle marker and the end of your route with a Red Circle marker. You can click on any marker to add some descriptive text. On the Start marker you can set a start date and time. If you have a terrain profile data for your route, then the End marker will show an ETA and how long before or after sunset that is.
A text box is used to show the length etc. of your route. Click on the tab or double click the text box to cycle through the available formats. Some of the formats are for area, and will shade the inside of a polygon built from your route.
This is the 'Magic' bit. Press the button to enable or disable 'Magic' path routing. Many local authorities have release their Public Right Of Way (PROW) data as 'Open Data'. Barry Cornelius of rowmaps.com has done a fantastic job of collating these releases. For WTP, I have processed them so that as you hover over the map, whole path sections are shown and may be added to your route with a single click. If you start a route with a path, click near the end you want to start at. To add a path to a route click on it. If your route ended with a clicked path, the new path will be joined to it as the 'Crow Flies'. If your end of route was not a path, then a best guess at where you want to join the path and which way you want to go is made.
Use this button to hide your route. When the button shows like this, you can press it to restore the previously hidden route. If you start a new route whilst one is hidden, the hidden route will be discarded.
Use this button to reverse you route.
Use this button to cycle through the available colours for drawing you route.
Use this button to undo or remove the last leg of the route.
Use this button to perform a terrain profile lookup of your route. The button will change to , the 'Legs' of your route will be coloured according to gradient (red for up, blue for down) and total ascent, descent and a hiking time estimate will be shown. To turn the look up off, press the button again .
When terrain data is available for all the Legs of your route, press this button to show a profile display of you route. Press the button again to hide the display. You can move the display to one side, and leave it on whilst you construct or adjust your route.
Press this button to bring up the Import / Export dialogue. Routes may be exported as GPX Tracks or GPX Routes to the on screen text area or to a local file. Waypoints can be included in the export. Import can be from the text area, from a URL on the text area or from a local file. WTP will do its best to break up your import into sensible Legs e.g. by introducing a Leg on a Track or Route near a Waypoint.
Once you have a route on screen, press this button to print a Route Card. The printout will use the same map Base Layer and Zoom as your Left/Top/Only map. The layout is rendered for A4 portrait printing.

Use the final tab to roll up or hide the controls. Useful on smaller screens.

That's it. I hope you enjoy it. If you have any questions please ask by email bill.chadwick2@gmail.com