diff --git a/css/main2.css b/css/main2.css index 6d3abb79a..cba0249be 100644 --- a/css/main2.css +++ b/css/main2.css @@ -389,6 +389,14 @@ ul#homenu li { } /*end of 2020.01 fix*/ +/* created for blocks of URLs on the samme subject */ +div.text-box { + width: 40%; + padding: 10px; + border: 5px solid gray; + margin: 0; +} + /*caves*/ table#cavepage { background: none repeat scroll 0 0 #FFFFFF; diff --git a/handbook/computing/i/F-Droid_Logo_4.svg.jpg b/handbook/computing/i/F-Droid_Logo_4.svg.jpg new file mode 100644 index 000000000..28dbf11ae Binary files /dev/null and b/handbook/computing/i/F-Droid_Logo_4.svg.jpg differ diff --git a/handbook/computing/i/dkma.jpg b/handbook/computing/i/dkma.jpg new file mode 100644 index 000000000..b45f84515 Binary files /dev/null and b/handbook/computing/i/dkma.jpg differ diff --git a/handbook/computing/i/osmand-icon.jpg b/handbook/computing/i/osmand-icon.jpg new file mode 100644 index 000000000..9704bd577 Binary files /dev/null and b/handbook/computing/i/osmand-icon.jpg differ diff --git a/handbook/computing/l/F-Droid_Logo_4.svg.html b/handbook/computing/l/F-Droid_Logo_4.svg.html new file mode 100644 index 000000000..50ff6932c --- /dev/null +++ b/handbook/computing/l/F-Droid_Logo_4.svg.html @@ -0,0 +1,24 @@ + + + + + +F-droid logo + + + + + +

F-droid logo

+
+
+ +

Downloaded Creative Commons

+ + +

Photo © Philip Sargent, 2026

+ + +
+ + diff --git a/handbook/computing/l/dkma.html b/handbook/computing/l/dkma.html new file mode 100644 index 000000000..1000735fb --- /dev/null +++ b/handbook/computing/l/dkma.html @@ -0,0 +1,24 @@ + + + + + +Don't Kill My App logo + + + + + +

Don't Kill My App logo

+
+
+ +

downloaded loga

+ + +

Photo © Philip Sargent, 2026

+ + +
+ + diff --git a/handbook/computing/l/osmand-icon.html b/handbook/computing/l/osmand-icon.html new file mode 100644 index 000000000..879943118 --- /dev/null +++ b/handbook/computing/l/osmand-icon.html @@ -0,0 +1,24 @@ + + + + + +OSMand + + + + + +

OSMand

+
+
+ +

OSMand icon, Creative Commons

+ + +

Photo © Philip Sargent, 2026

+ + +
+ + diff --git a/handbook/computing/myphone.html b/handbook/computing/myphone.html index f11ad5479..896be380f 100644 --- a/handbook/computing/myphone.html +++ b/handbook/computing/myphone.html @@ -2,9 +2,13 @@

My Phone on Expo

Before Expo

Since 2019 it has become apparent that many people have not been properly prepared for Expo.

+

Since 2019 it has become apparent that many people have not been properly prepared for Expo.

This is what you need to do: +

  +

+  
+For the latest updates on why "battery saver" kills accurate location for the most recent phones, go to: dontkillmyapp.com +
  • Fix the seriously broken default for recording your GPS track when you are walking in the plateau.
       +
    +
  • Download and install OSMand +
  • Download and install GPStest +  +

     
    @@ -67,6 +81,9 @@ tbd

    You will probably be familiar with real-time, continuous sharing of location using Google Maps or Apple, but there are several apps that do this.

    Note that you do want continuous location sharing, so that when you fall down a hole and lose signal, we know where the top of the hole is. + +

    You will probably be familiar with real-time, continuous sharing of location using Google Maps or Apple, but there are several apps that do this. +

    Note that you do want continuous location sharing, so that when you fall down a hole and lose signal, we know where the top of the hole is.

    Disabling GPS "energy saving" modes

    Why

    @@ -79,11 +96,13 @@ tbd

    If you have standard battery saving set up, when you start up OSMand and start recording a track, it will do a popup telling you about how to turn off battery saving.

    What you need to do seems to be correlated with how expensive your phone is. A Xioami Redmi 12 phone in 2024 worked with just the OSMand and battery saving fetures disabled as described above. But in 2025 a Blackview Wave8 phone would not produce a useable OSMand track at all until the "GPStest" app (see below) was also run continuously and with notifications and logging enabled. +

    What you need to do seems to be correlated with how expensive your phone is. A Xioami Redmi 12 phone in 2024 worked with just the OSMand and battery saving fetures disabled as described above. But in 2025 a Blackview Wave8 phone would not produce a useable OSMand track at all until the "GPStest" app (see below) was also run continuously and with notifications and logging enabled.

    Temporary Google Photos

    +

    When anyone shares photos on a "Shared Album" in Google Photos, they are only visible so long as the original photographer keeps the photos on their device: there are loads of photos by Harry Kettle from 2023 which are visible only as blank rectangles on the Shared Album because he has cleared out his photo album on his google account. (This really is a "share" not an "upload".)

    So unless the photo is utterly trivial and disposable, please also upload the photos using the "Upload Photos" page on the website before you delete them from your device.

    We would rather you didn't use Google Photos at all really, but people will willy-nilly, so let's at least use the same Google photos album each year. @@ -96,6 +115,7 @@ Go on to Saving your GPS tracks Go on to Next survey guide page - 'Base Camp: getting it in to the computer'

    +

    Your phone on expo - Do not select the "high accuracy" location setting on your phone (this page)
    GPS essentials on the plateau - Safety information
    diff --git a/handbook/computing/t/F-Droid_Logo_4.svg.jpg b/handbook/computing/t/F-Droid_Logo_4.svg.jpg new file mode 100644 index 000000000..98ae26eda Binary files /dev/null and b/handbook/computing/t/F-Droid_Logo_4.svg.jpg differ diff --git a/handbook/computing/t/dkma.jpg b/handbook/computing/t/dkma.jpg new file mode 100644 index 000000000..faccf707e Binary files /dev/null and b/handbook/computing/t/dkma.jpg differ diff --git a/handbook/computing/t/osmand-icon.jpg b/handbook/computing/t/osmand-icon.jpg new file mode 100644 index 000000000..8b71635d4 Binary files /dev/null and b/handbook/computing/t/osmand-icon.jpg differ diff --git a/handbook/essentials.html b/handbook/essentials.html index 2302bff3d..a7067c577 100644 --- a/handbook/essentials.html +++ b/handbook/essentials.html @@ -20,8 +20,8 @@

    What EVERYONE needs to do

    Don't be misled by the apparent simplicity of the tracks. The plateau is very broken and is an unremitting extent of cliffs, holes and impassable dwarf-larch scrub ("bunde" as it is known on expo). You can be 5m from the route and have lost it entirely. The walk to and from @@ -169,9 +169,11 @@ This should work the same way whether you have an iPhone or an Android phone.

    This (nerds only) has been moved to a separate page: regenerating essentials.gpx.

    +
    +
    Your phone on expo - Do not select the "high accuracy" location setting on your phone
    - +GPS essentials on the plateau - Safety information (this page)
    Photo GPS - Is unreliable unless you follow procedure
    -Locating entrances by GPS - from the survey handbook section
    -
    + Locating Entrances - expo recommended methods
    +
    diff --git a/handbook/survey/gps.htm b/handbook/survey/gps.htm index e6b42bd84..b63a32f0b 100644 --- a/handbook/survey/gps.htm +++ b/handbook/survey/gps.htm @@ -9,6 +9,8 @@

    First actions

    First of all, you need to set up your phone in "expo mode" for recording locations on the plateau reliably. This is not just some technical settings, it also means a particular style of useage whch you need to learn. + +

    Which point to fix

    @@ -28,8 +30,14 @@ otherwise with a restricted view of the sky, then choose instead a good landmark with a wide, clear view of the sky, and with at least two survey shots of the entrance.

    -

    Yes, you will have to manually do a surface survey leg using your survey instruments between the GPS point and the cave entrance tag station, and record that in your cave survex file. +

    Yes, you will have to manually do a surface survey leg using your survey instruments between the GPS point and the cave entrance tag station, and record that in your cave survex file.

    Calibrate/document your phone's capabilities

    +
       +
    +Install the "GPS Test" app, this one: GPS TEST and check whether your phone is using SBAS "Satellite-based Augmentation Services", which is another name for EGNOS, the differential GPS system. +You need to record if SBAS is in operation whenever you record the position of a cave entrance (and ideally whenever you take a photo too, but that would be unrealistic). [ Philip Balister takes a screen-shot of the GPStest screen whenever he want a proper GPS location. A notebook and pencil are also valuable adjuncts when looking at lots of entrances: use the timestamp on the screenshots to correlate everything. ] + +

    Since 2018 we have differential GPS which renders historical advice obsolete (e.g. Wookey's 1996 article) but altitudes are still always inaccurate and GPS devices don't generally tell you how inaccurate they are. Also phones are now much more complicated than the dedicated GPS devices used in the past. It is now the phone itself we have to worry about, not just GPS. Phones try to be "helpful" these days and do not tell you what they are doing. @@ -75,10 +83,19 @@ too.

    We all use the same coordinate system WGS84 these days, so the extensive discussion on coordinate systems has been moved to a different page. If you are really interested you can read Olaf's articletoo. +

    The future

    +

    Location fixing: How to obtain a fixed point for a cave survey (2020) .Galileo High Accuracy Service (HAS) was due to become available in 2024, which would offer RTPPP for free around the world - but it's still not really working for most people. + This is an excellent article and nearly all of it is still absolutely true, e.g.: +

    Keep the device very still. If the position shown by GPSTest slowly refines then stops updating within a minute or two, or shows only the last digit changing slowly, then your device cannot be used for averaging. A device with 1 metre accuracy still shows the 6th and 7th decimal place digits of the longitude and latitude updating every second or so (that is a roughly 10 cm wobble every second). Unless your device can actually do 1 cm accuracy, you should be seeing those numbers change! In general, this makes most phones unusable for this purpose"
    +

    Unfortunately RTPPP has not actually caught on [2025] and it is still only available for experts and phones supporting L2 and L5 frequencies have been slower to appear than we hoped. Read Wikipedia on Real-time kinematic positioning (RTK).

    Next survey guide page - 'Base Camp: getting it in to the computer'
    +
    +
    Your phone on expo - Do not select the "high accuracy" location setting on your phone
    GPS essentials on the plateau - Safety information
    -Photo GPS - Is unreliable unless you follow procedure
    +Photo GPS - Is unreliable unless you follow procedure
    + Locating Entrances - expo recommended methods (this page)
    +
    diff --git a/years/2024/log_entries/2024-07-21c.json b/years/2024/log_entries/2024-07-21c.json index b351a3c08..2fd537fc6 100644 --- a/years/2024/log_entries/2024-07-21c.json +++ b/years/2024/log_entries/2024-07-21c.json @@ -3,7 +3,7 @@ "title": "Photo - Photo GPS is unreliable", "place": "Photo", "other_people": "", - "text": "During this same trip walking to Geschandalm, later analysis of the GPS locations of various photos showed a lot of variability. \nThis is a particularly clear example where the location is obvious in the photo (it is definitely on the path) \nbut the GPS location stored by the phone camera is 60m away.\n

    \nI had one phone (Xioami) continually tracking my location (using OSMand) which produced the GPX track, \nand another (Pixel) used for photographs. \nThe GPS data in the photos is clearly completely wrong for some of the photos - \npresumably because I hadn't left enough time for it to get a decent GPS fix before taking the photo. \nThis is particularly clear when there is a well-identified spot in the photo, \nsuch as this one right by the shady cliff (photo EXIF GPS locations are orange dots):
    \n\n \n \n

    \nThe lesson to take away from this is to always take TWO photos at any one position, and throw away the first one. \nThis will nearly always work for most people, and is sufficiently simple that even undergraduates can remember it.\nAlternatively, always continually record a GPS track on the phone you are using to take photos with - \nthough this is unfortunately not always reliable either, as the camera app tends to cache locations and doesn't always \nget a fresh one from the \"location\" module in the phone.\n

    \n
    ", + "text": "During this same trip walking to Geschandalm, later analysis of the GPS locations of various photos showed a lot of variability. \nThis is a particularly clear example where the location is obvious in the photo (it is definitely on the path) \nbut the GPS location stored by the phone camera is 60m away.\n

    \nI had one phone (Xioami) continually tracking my location (using OSMand) which produced the GPX track, \nand another (Pixel) used for photographs. \nThe GPS data in the photos is clearly completely wrong for some of the photos - \npresumably because I hadn't left enough time for it to get a decent GPS fix before taking the photo. \nThis is particularly clear when there is a well-identified spot in the photo, \nsuch as this one right by the shady cliff (photo EXIF GPS locations are orange dots):
    \n\n \n \n

    \nThe lesson to take away from this is to always take TWO photos at any one position, and throw away the first one. \nThis will nearly always work for most people, and is sufficiently simple that even undergraduates can remember it.\nAdditionally, \n

    1. always continually record a GPS track on the phone you are using to take photos with - \nthough this is unfortunately not always reliable either, as the camera app tends to cache locations and doesn't always \nget a fresh one from the \"location\" module in the phone,\n
    2. Take a screenshot of the GPStest app showing current location and accuracy data. You can get it from F-Droid or Google Play Store.
        \n
      \n
    \n

    \n
    \n
    \nYour phone on expo - Do not select the \"high accuracy\" location setting on your phone
    \nGPS essentials on the plateau - Safety information
    \nPhoto GPS - Is unreliable unless you follow procedure (this page)
    \n Locating Entrances - expo recommended methods
    \n
    ", "slug": "2024-07-21c", "time_underground": 0.0, "author": {