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Big Sur Trailmap for Smartphones

Updated: Jul 16, 2021

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. 

Jump down to Smartphone vs GPS info

App map warning:   Smartphone apps generally use USGS or OpenStreetMap derived topographic maps. both of which have incorrect or incomplete trail and 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 reliable 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. 

Smartphone trailmaps do not display any closures !
(due to the ephemeral nature of closures)
Trail and road closure information must be obtained from the on-line interactive maps,
e.g.  trail conditions interactive map





The following 3 methods display Big Sur Trailmap data in a smartphone
use whichever best meets your needs


• Trailmap GPX File in GPS App

Many, but not all, smartphone 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 the Big Sur Trailmap lines and points, i.e. trails, camps, water sources, etc., by importing this 2.3MB GPX file(Note: it does not contain "lost" trails or camps.  Last update: Jul 29) The file's copyright restricts it to personal use, i.e. it is not to be promulgated to a public source such as AllTrails or OpenStreetMap or Gaia Cloud (as these abusers have.)

This method's advantages are:
    • can be free  (depending upon app)
    • allows high zoom levels (to max permitted by app)
    • availability in most smartphone GPS apps
    • trailmap lines and icons are always on the phone, even outside internet coverage;
    • tapping on trail/icon will display associated info (on most apps)
Disadvantages are:
    • mixes trailmap lines and points with all other lines and points you have in the app
    • displays trailmap line colors and icons differently from the on-line trailmap
    • updating may require deleting existing lines and points before exporting new trailmap file
      (depends upon whether app overwrites or re-names trails with same name)       (note: shows only longer-term closures)

I've found these links giving GPX import instructions for the following apps: 
[Note: an alternative Trailmap usage for these apps is given further below, in Trailmap Tiles in GPS App - users should decide which method they prefer.]

[For undecided Android users: Gaia vs Backcountry Navigator - plus Gaia warning]

    Backcountry Navigator (for android - "Pro" version = one-time $12):  Section 4.e of manual
    Gaia GPS (for android & iPhone - free for gpx-only usage):  GPX import instructions
      (some Gaia users report that waypoint name information is not being displayed - it can be made to appear by simplying "editing" the waypoint, the name then magically appearing)
    OruxMaps (for android - free):  in Tracks/Routes screen, use "Import" button - see Engish Manual
If you know a link for instructions for another app, let me know and I will add it here

Abusers:  Gaia GPS provides a "cloud" into which some users have uploaded my copyrighted GPS files.   Unfortunately, Gaia cloud is unethically (and illegally) stripping copyright information those such files (in violation of DMCA laws)


• Trailmap Geospatial PDFs in GPS App

Several mobile phone GPS apps:
      Avenza Maps  (for android and iPhone - free for 3 loaded maps, $30/yr for unlimited maps)
      Gaia GPS (for android & iPhone - $40 yearly for offline storage - note that any 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)
      Mappt  (for android - $30/yr, free version for testing)
      [Also Adobe Acrobat Reader  (for android and iPhone - free) - but it's not a GPS app as it cannot display your current location]

For users of such apps, I provide 3 geospatial PDF Trailmaps to cover the Big Sur area 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:
    • free (for limited use)
    • displays trailmap lines and icons just as on the on-line trailmap
    • trailmap is always on the phone, even outside internet coverage;
    • allows trailmap to be easily enabled or disabled
Disadvantages are:
    • limited zoom capability
    • updating requires uploading the latest trailmap files


• Trailmap Map Tiles in GPS App
FWIW, this is the method I use on my own smartphone

Smartphone 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 smartphone, 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. 

Some smartphone GPS apps have a "custom map" feature:
      BackCountry Navigator (for android - "Pro" version = one-time $12 for off-line storage)
      Gaia GPS (for android & iPhone - $40 yearly for offline storage - note that any downloaded maps require renewal for access)
      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.  Note: an alternative Trailmap usage is given above, in Trailmap GPX File in GPS App and for OruxMaps also in Garmin Trailmap in GPS App - users should decide which method they prefer.

This method's advantages are:
    • displays trailmap lines and icons ala the on-line trailmap
    • allows trailmap to be easily enabled or disabled, with a single click
    • latest map available when within internet coverage  (note: shonws only longer-term closures)
Disadvantages are:
    • free only for OruxMaps
    • trailmap must be stored prior to use outside internet coverage areas 
    • image only - tapping on trail/icon will not display any info
    • zoom limited by tile maximum (level 16 = 2.0 meters/pixel)

Big Sur Trailmap tiles only cover the Big Sur region - outside there, blank tiles will be displayed.   Also, only zoom levels 6-16 will be displayed.

[For undecided Android users: Gaia vs Backcountry Navigator - plus Gaia warning]

Note:  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 select it from that list, steps which of course depend on the app

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 the "Technical details" section below and downloading its "TileJSON" file.  Be sure to note the location where it's being downloaded!  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 (~6min) occurs 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 smartphone.  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. 

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 [click to download "BigSurTrailmap.json"] for setup.  PNG size has been reduced using optimization algorithms.  Downloading the complete tile set requires ~400Mb of storage.  Tiles are updated weekly. 

Example Tile: below is the highest zoom (level 16) tile covering the Big Sur Station and Pine Ridge Trail trailhead (36.24689°N,121.78047°W) with a green trail line, magenta "closed trail" line, gray road lines, Big Sur Station icon, blue 0.3 mileage (between blue dots, when over 0.1 mi) overlying a USGS topo map [with an incorrectly-located dashed-line trail] In short, the map should appear with trail/usetrail/road line colors and camp/water/summit icons all ala the printable Big Sur Trailmap, which is ala the on-line Trailmap with the addition of distances between blue dots (when over 0.1 mile)
example tile

Interactive Tiles Viewer: this link provides an interactive viewer to let you see how the tiled map will appear in your smartphone app (except the app will have its own tools, etc.) - you can zoom/move the map as an app would:
  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 not 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, displaying the tiles at their highest zoom level is needed to effectively display the stream crossing information. 

If you know of other GPS apps which can use this tiled map, let me know and I will add that info here. 

FYI on the background map: 
        The current tile background map is the venerable USGS quadrangle map, not the modern USGS topo map which is the default for my on-line Trailmap and Trail Conditions maps.  For the latter maps, a user can select a different background if deemed preferable - but that's not possible for the tiled maps, so I must decide which background is better for them. 
      In my opinion, the modern USGS map has a cleaner and more attractive look so trail lines look better on it - so it's the on-line maps default.  However, it does not have as much detailed information and its lighter contour lines and smaller text labels are less easily read.  Having to choose between "better looking" or "more useful in the field", I've opted for the latter. 




Smartphone vs GPS

In my view, smartphone maps are a "middle step" in a heirarchy:
    • paper maps
    • smartphone maps
    • GPS maps

Smartphone maps offer advantages over paper maps, particularly being able to show your location on the map and to zoom in/out - but also have some disadvantages, such as not showing as much of the forest and being dependent upon a battery.  In turn, GPSes have features not found in smartphone maps, such as displaying information associated with a line or icon and computing "along-trail" distances. And GPSes have equipment advantages of being more rugged, waterproof, (often) having a better GPS antenna (reducing accuracy problems in canyons or under tree canopies) and screens designed to be used outdoors and viewed in sunny locations (smartphone and GPS screens use differing technologies - so smartphones are more readable, and use less battery, in dimmer environments whereas GPSes are the opposite, i.e. are more readable and use less battery in brighter surroundings).  But GPSes also have their disadvantages, notably needing to purchase/carry an additional piece of equipment.  And some differences can be seen as either a positive or a negative, depending upon priorities - for example, the larger screen of a smartphone can aid map reading but also can make handing and storage more awkward. 

Those wanting an "electronic map" and already owning a smartphone should first utilize a smartphone app - it may well meet all your needs.  If you later want a more capable "electonic map", you can step up to a GPS.  (My thoughts on GPs selection)



    Smartphone apps use a "raster" map whereas GPS's use "vector" maps.   Each has advantages/disadvantages..  App maps tend to be prettier and show more detail (eg buildings, facilities, etc.) whereas GPS maps have additional capabilities useful for hard-core map users.  As a bushwhacker, I find a GPS (with vector maps) has these advantages over raster map apps:  [2018 update: the Gaia "vector" topo map can do the last three of these.]
      • can be operated with one hand while I continue to hike (for a "button style" GPS)
      • gives remaining along-trail distance to a destination as I hike
      • gives elevation of a contour line when I place the cursor over it
      • gives name of a trail, stream, etc. when I place the cursor over it
      • displays to very high zoom levels, eg: full-screen width ~60 ft
      • provides different detail depending upon zoom level  (eg: stream crossings shown at higher zooms)
      • displays constant line widths and text/icon sizes at all zoom levels

    While working on this page I came across a comparison of smartphone app vs traditional GPS, which gives useful options for getting around smartphone limitations of poorer battery life, poorer gps accuracy, and poorer ruggedness.  Unfortunately it also tries to sell instead of being objective (since it promotes a smartphone app) and some assertions are incorrect - for example, Garmin users are not "locked into expensive, proprietary Garmin formats" since there are many free Garmin-format maps available on the web (apparently the writer never heard of gpsfiledepot.com).  I've also found this detailed discussion of battery saving procedures - but I did note that among its "battery saving" tips it includes turning off tracking, whereas for me having a saved track is a main reason for carrying a GPS/smartphone.  Be aware that GPS uses continual satellite accessing, preventing a smartphone from going into "sleep" mode - so battery life will be less than you are used to.  BTW, unmentioned in the above article is what I personally find, having used both, the biggest disadvantage of a smartphone over a GPS - being unable to see details such as contour lines on the map in bright sunlight, despite having screen brightness at its max. 

    Of course, a fundamental difference and advantage of a smartphone is its non-map features (e.g. taking a photo, making a phone call, using a plant identification app, etc. - though of course many of those are on-line, which is not possible in most wilderness).  This follows the general rule (as I've experienced with airplanes) that one must often choose between something which can do a specific task very well vs. something which can do a greater variety of tasks but is not quite as good for a specific task. 

Jack Glendening
Trailmap Forum