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Big Sur Trailmap for Smartphones

updated: Jan 16, 2025
Note:  I have limited hiking experience with a smartphone, since I usually use a GPS while hiking.  Information presented here is based upon experimentation with GPS apps on my android phone and a friend's iphone, so is likely incomplete.  If you think something needs to be added, post to the Trailmap Forum to educate me and I will add that information to this webpage. 

App map warning:   Smartphone apps generally use OpenStreetMap or USFS derived maps, both giving incorrect or incomplete trail/camp locations in the Ventana/SilverPeak wilderness areas.  So the focus here is on apps which can use the accurate Big Sur Trailmap data I provide.  FYI: for Big Sur trails, all commercially-printed Big Sur maps are more accurate than those in smartphone apps.

Cell connectivity:  much of Big Sur has no wireless phone reception, especially in the wilderness, so requires a GPS-enabled smartphone and "off-line map" software - all software described below has that capability, but some are easier to utilize. 



Three ways of displaying Big Sur Trailmap
in a  smartphone GPS app
use whichever best meets your needs: GPX or PDF or Tiles



Gaia screenshot
(click for larger view)

Many, but not all, phone GPS apps can import a GPX file to display lines ("tracks"), such as trails, and points ("waypoints"), such as camps.  With such apps, you can add Big Sur Trailmap lines and points, i.e. trails, camps, and water sources, by importing a single GPX files containing all trailmap lines and points. 


This method's advantages are:
• can be free  (depending upon app)
• allows high zoom levels (to max permitted by app)
• tapping on line or point will display associated info (on most apps)
• versions with and without trail conditions/closures available
• available in most smartphone GPS apps

This method's disadvantages are:
• mixes trailmap lines and points with other lines and points in the app
• may display trailmap line colors and points differently from on-line trailmap
• cannot display/hide all trailmap lines and points with single click
• updating may require deleting existing lines and points before exporting new trailmap GPX file  (depends upon whether app overwrites or re-names trails with same name)

Apps allowing GPX import:
• Gaia GPS (for android & iPhone - free for gpx-only usage)
Import Instructions: 'Import GPX' webpage
 (some Gaia users report that waypoint name information is not being displayed - it can be made to appear by simply "editing" the waypoint, the name then magically appearing)
• Backcountry Navigator (for android - "Pro" version = one-time $15 [Jan.2025])
Import Instructions: Section 4.e of manual
• OruxMaps (for android - free)
Import Instructions: in Tracks/Routes screen, use "Import" button - see English Manual
[If you know a link for instructions for another app, let me know and I will add it here]


GPX file download:
with trail conditions/closures
line color ⇒ trail/road condition/closure
(Valid until conditions/closures change)
[file updated: Mar 28]
GPX file download:
sans trail conditions/closures
line color ⇒ trail/road type
(Valid for indefinite period)
[file updated: Mar 28]


Notes:
• To reduce file size, "lost" trails and camps are not included.  Included points are only camps, campgrounds, use camps, and water sources.
• Line color is ultimately set by the app - what you see may differ from gpx internally-specified color.
• Both gpx files updated daily to match latest on-line maps.
• File size ~2.8GB




Avenza screenshot
(click for larger view)

Several phone GPS apps can display geospatial PDFs.  So I provide two geospatial PDF Trailmap files [link], one including current trail conditions/closures (valid until conditions/closures change) and the other not.  Many find these apps simple to use and meet their need to see where they are on a map.  But note that their mapping display is limited, being for a single map at all zoom levels and so providing fewer zoom levels, since lines/icons must get larger/smaller when zooming in/out (whereas the apps described in 'Trailmap Tiles in GPS App'" below can provide differing detail at different zooms - personally, I consider these more capable than the PDF apps and so a better choice if willing to pay for an app.). 


This method's advantages are:
• can be free (depending on app)
• trailmap displayed exactly (lines,icons,background ala the on-line trailmap)
• trailmap can be easily enabled/disabled, with single click
• versions with and without trail conditions/closures available  (but former only valid until conditions/closures change)

This method's disadvantages are:
• limited zoom capability (depends on app)
• adding info for line/icon tap display requires additional steps

Apps allowing GeoPDF import:
• Avenza Maps  (for android and iPhone - free for 3 loaded maps, $35/yr for unlimited maps [Jan.2025])
• Gaia GPS  (for android & iPhone - $60 yearly for offline storage [Jan.2025] - note that downloaded maps require renewal for access)
note: "Trailmap Map Tiles in GPS App" section below provides a more sophisticated map for Gaia users, since zooming in brings in higher-resolution images
• Caltopo  (20/yr for offline layers [Jan.2025])
• Adobe Acrobat Reader  (for android and iPhone - free)
but is not a GPS app as it cannot display your current location]

What I use on my smartphone

Interactive tiles sampler
(can pan, zoom)
(click here for full size)

Phone GPS apps, such as Google Maps, typically display maps produced by a map tile server, accessed via the internet.  (Tiles are small pieces of the map.)  Since only map tiles around the active location are kept ("cached") on the phone, this saves memory - but when internet access is lost, only currently cached tiles can be viewed.  For wilderness use, the below apps circumvent this problem with an "off-line-map" capability, allowing a user-specified area to be downloaded and stored so the map can still be displayed when internet access is lost.  Currently these tiles do not include any trail condition/closure information.  (These tiles can also be used as a background map in GIS programs such as ArcGis and QGIS, imported as "XYZ Tiles" - see "Technical details" below.)


This method's advantages are:
• trailmap displayed exactly (lines,icons,background ala the on-line trailmap)
• trailmap can be easily enabled/disabled, with single click

This method's disadvantages are:
• free only for OruxMaps
• image only - tapping on trail/icon will not display any info
• zoom limited by tile maximum (level 16 = 2.0 meters/pixel)
• no trail condition/closure info
[An alternative for these apps is in section Trailmap GPX File in GPS App]

Apps allowing "custom map" feature:
• Gaia GPS (for android & iPhone - $60 yearly for offline storage [Jan.2025] - note that downloaded maps require renewal for access)
• BackCountry Navigator (for android - "Pro" version = one-time $12 for off-line storage, "XE" version $15/year [Jan.2025])
• OruxMaps (for android - free) allowing use of map tile servers for map display.  For such users I've created a tile server displaying Big Sur Trailmap lines and icons on a USGS topo background. 
[If you know of another GPS app which can use tiled maps, let me know and I will add that info here.]


General app info:
• The below instructions only add Big Sur Trailmap to the list of available map backgrounds - to use it as the actual displayed background layer requires additional steps to make it the active background, steps which of course depend on the app
• Big Sur Trailmap tiles only cover the Big Sur region - outside it, blank tiles will be displayed.   Also, only zoom levels 6-16 will be displayed.

Specific app info:
BackCountry Navigator has a "custom map" feature for displaying a user-specified tile map.  To add the Big Sur Trailmap, under the "Map Layers" icon, select "More Map Sources" and tap its 3-vertical-dot top-right menu to select "Custom Map Source".  Then tap "New Custom Map Source" and enter the following fields (tap and use keyboard):  Name: "Big Sur Trailmap"  MinZoom: "6"  MaxZoom: "16"  TileType: "PNG"  TileUpdate: "None"  Url: "https://bigsurtrailmap.net/TRAILMAP/TILES/{$z}/{$x}/{$y}.png" - then tap "Save".  This will return to the "Custom Map Source" screen - tapping the newly added "Big Sur Trailmap" line and then "Use" will display the Big Sur Trailmap (note: the alternative choice "Edit/View" allows you to check for typing errors, should there be a problem).  Note that tapping on the "Map Layers" icon will indicate that the "Online & Cached Tiles" selection is now "Big Sur Trailmap".  Also note that after switching to a different map, "Big Sur Trailmap" and other previously used maps are quickly available by tapping on the current map source on the "Map Layers" screen.  To display when out of internet/phone service, you must download the tiles to your phone (345Mb storage for all tiles) - see map download help page.  (Summary: with Big Sur Trailmap displayed as "Online & Cached Tiles", zoom out to show entire map area, tap "Layers" icon, tap "Select Areas for Download", drag to create selection rectangle(s) covering map area, tap "Folder" icon, set "Max Zoom" 16, tap "Save to new Named Map Folder", input "Big Sur Trailmap", tap "Create", tap "Begin Download", wait for download to be completed - note final 1% processing may take ~10 mins, do not cancel prematurely).  Remember that the displayed on-line map will always be up-to-date whereas the downloaded map will require updating to be current. 
Gaia GPS users can add the Big Sur Trailmap to your "Layers" by going to "Technical details" below and downloading its "TileJSON" file.  Be sure to note the folder on the mobile phone where it's being downloaded to!  The file name is "BigSurTrailmap.json".  Then in Gaia go to the map page and click the "+" icon and then "Import" - navigate to the folder where the JSON file is, then click on the file to import.  (Ignore any references to trails/POIs, which can also be loaded in this fashion.)  You should now see "BigSurTrailmap" in your "Layers" screen - touch to make it the displayed map.  (You can delete the downloaded file.) To display when out of internet/phone service, you must download the tiles to your phone (330Mb storage for all tiles) - see iOS map download help page or Android map download help page.  Note: when choosing to display a "Saved" map, after pressing "Show on Map" a considerable delay can occur (~6min) before the map is displayed.  Remember that the displayed on-line map will always be up-to-date whereas the downloaded map will require updating to be current. 
OruxMaps can display maps from a tile server, including off-line by pre-loading onto the mobile phone.  To add Big Sur Trailmap tiles, after installation find directory oruxmaps/mapfiles on the memory card - after making a backup copy of its onlinemapsources.xml file, use a text editor to insert (be careful!) this text into file onlinemapsources.xml, just after the "<onlinemapsources>" tag and just before the following "<onlinemapsource uid=..." tag.  Big Sur Trailmap will then appear as a selection under "ONLINE" "LAYERS" "US".  Alternative to avoid editing:  copy this 2018 version of onlinemapsources.xml with Big Sur Trailmap added to that directory and re-name it as onlinemapsources.xml.  [Tested: Aug2018]  To display when out of internet/phone service, you must download the tiles to your phone.  For more information, see the English manual.  Remember that the displayed on-line map will always be up-to-date whereas the downloaded map will require updating to be current. 


Example Tile:
Below is the highest zoom (level 16) tile covering the Big Sur Station and Pine Ridge Trail trailhead.  The map has trail/usetrail/road line colors and camp/water/summit icons all ala the printable Big Sur Trailmap, which adds distance between blue dots (when over 0.2 mile) to the on-line Trailmap.  This illustrate the high-resolution capability of these tiles.

example tile


Interactive Tiles Sampler:
This link provides an interactive viewer to let you see how the tiled map will appear in your mobile phone app (except the app will have its own tools, etc.) - you can zoom/move the map as an app would:
  Full-screen tiles viewer


Stream Crossing Icons:
Some trails cross the same stream multiple times, sometimes in quick secession - for example, the Carmel River Trail crosses the Carmel River 27 times!  Since knowing whether the next crossing is near or far can be useful, for such trails I've added crossing icons . But the icon must be small since if larger would show only a single icon at crossings which are very close together, negating their usefulness.  So if hiking such trails, you must display the tiles at their highest zoom level to effectively view the stream crossing points. 


Technical details:  (used by some apps)
• Tiles are accessed at subdirectories of https://bigsurtrailmap.net/TRAILMAP/TILES/, providing 256x256 pixel PNG tiles with directory ordering "ZXY", Y increasing southward (i.e. GoogleMaps/OSM/XYZ format) (Addendum: have added links such that "Y increasing northward", OSGeo TMS format, also works). 
• Zoom levels are 6 through 16 (zoom6-13=100Kmap,zoom14-16=24Kmap).
• Bounds are 35.758° to 36.415° latitude and -121.874° to -121.162° longitude.
• The top-most tile is https://bigsurtrailmap.net/TRAILMAP/TILES/6/10/25.png
• Some apps can use a GeoJSON/TileJSON tile information file for setup [click to download "BigSurTrailmap.json"]
• PNG image sizes have been reduced using optimization algorithms.  Downloading the complete tile set requires ~400Mb of storage.
• Tiles are updated weekly.

Background map FYI 
  The PDF background map used at higher resolutions is the modern USGS "shaded terrain" National Map, which is the default for my on-line interactive maps, rather than the venerable USGS quadrangle map. The modern USGS map has a cleaner and more attractive look and does not have the often-incorrect trail lines found on the venerable quadrangle maps.