troggle/templates/eastings.html

{% extends "base.html" %}
{% block title %}Cave Entrances and other locations in UTM{% endblock %}

{% block content %}

<h1>Entrance locations</h1>

<p>
These first two tables are all the Caves which have <em>manual</em> locations specified as Northing/Easting coordinates in their Cave Entrance Description data. 
<p>
This report is to help you sort out and fix the bad data in our records. You can see from the tables here
that UTM data sometimes have Northings and Eastings swapped, or UTM is used when it is intended to be 
BMN and vice versa.

<p>All surveyed caves have entrance locations fixed by the survex data, as survey stations with names such as 
1623.p277a . This is the reliable data and is shown in the third table. The reason why we have manual data is because when a 
cave entrance is first discovered, it is not yet connected to the survey network. But we want to record its position
otherise we will lose it.

<p>
Coordinate systems in Austria are explained in:<br>
<a href="/handbook/survey/lasers.htm">Geographical fixed points on Loser</a><br>
<a href="/handbook/survey/coord2.html">GPS and coordinate systems</a><br>
<a href="/handbook/survey/coord.htm">Basic Coordinate Systems</a>.

<p>The data in the table immediately below has been hand-entered and is sometimes very wrong.
<p>The Lat. Long. coordinates are manually entered using a phone or a hand-held GPS device at (or near) the entrance.
<p>For the Cave column, if there is an official cave name, then it is shown. 
Otherwise whatever other name we can find for it is shown <em>in italics</em>.

<style> 
th, td {
  padding-left: 5px;
  padding-right: 5px;
</style>

<p>OK now for the nasty bit. Many of the older caves did not have easting & northing in UTM 33T at all, but (probably) in BMN and converting between BMN into UTM requires ellipsoids and bessel functions.. or we can just take a linear approximation, which is what I have done here:<br>
e.northingUTM = e.northingBMN + 5198919.918<br>
e.eastingUTM = e.easting + 374854.63<br>
Such converted eastings and northings are <em>in italics</em> in the table below. As you can see, some were wildly out.
<p>These magic numbers simply come from assuming that both BMN and UTM are in metres, and linear over our area, and then taking the avergage of the offsets for 5 locations, the 5 cave entrances at the bottom of this page: 
<a href="http://localhost:8000/handbook/survey/coord.htm#summary">Olaf's Coordinates</a>.
<p>This horrible approximation is accruate to ~8m in the northing and ~30m in the easting.
<table>BMN
<tr><th>Cave</th><th>Entrance slug</th><th>Easting</th><th>Northing</th><th>best tag easting</th><th>best tag northing</th>
<th>&Delta; x</th>
<th>&Delta; y</th>
<th>Distance (m)</th></tr>
{% for ent in ents %}
<tr>
  <td style="text-align:left">
  {% for c in ent.cavelist %}
    <a href="/{{c.url}}">
    {% if c.official_name %}
        {{c.official_name|safe}}
    {% else %}
        <em>{{c|safe}}</em>
    {% endif %}</a><br>
  {% endfor %}</td>
  <td style="text-align:right">{{ent.slug}}</td>
  
  <td style="text-align:right; {% if ent.bmn %}font-style: italic{% endif %}">{{ent.easting|floatformat:2}}</td>
  <td style="text-align:right; {% if ent.bmn %}font-style: italic{% endif %}">{{ent.northing|floatformat:2}}</td>

  <td style="text-align:right">{{ent.best_station_object.x|floatformat:2}}</td>
  <td style="text-align:right">{{ent.best_station_object.y|floatformat:2}}</td>
  <td style="text-align:right; {% if ent.bmn %}font-style: italic{% endif %}">{{ent.diffx|floatformat:0}}</td>
  <td style="text-align:right; {% if ent.bmn %}font-style: italic{% endif %}">{{ent.diffy|floatformat:0}}</td>
  <td style="text-align:right; {% if ent.bmn %}font-style: italic{% endif %}">{{ent.error|floatformat:0}}</td>
</tr>
{% endfor %}
</table>

<p>and now the GPS equivalents:
<table>
<tr><th>Cave</th><th>GPS Lat</th><th>GPS Long</th><th>best Lat</th><th>best Long</th><th>tag</th><th>tag Lat</th><th>tag Long</th><th>tag exact</th><th>exact Lat</th><th>exact Long</th><th>tag other</th><th>other Lat</th><th>other Long</th></tr>
{% for ent in gpsents %}
<tr>
  <td style="text-align:left">
  {% for c in ent.cavelist %}
    <a href="/{{c.url}}">
    {% if c.official_name %}
        {{c.official_name|safe}}
    {% else %}
        <em>{{c|safe}}</em>
    {% endif %}</a><br>
  {% endfor %}</td>
 
  <td style="text-align:right">{{ent.lat_wgs84|floatformat:6}}</td>
  <td style="text-align:right">{{ent.long_wgs84|floatformat:6}}</td>
  <td style="text-align:right">{{ent.lat|floatformat:6}}</td>
  <td style="text-align:right">{{ent.long|floatformat:6}}</td>
  <td style="text-align:right">{{ent.tag_station}}</td>
  <td style="text-align:right">{{ent.tag_ts.lat|floatformat:6}}</td>
  <td style="text-align:right">{{ent.tag_ts.long|floatformat:6}}</td>
  <td style="text-align:right">{{ent.exact_station}}</td>
  <td style="text-align:right">{{ent.tag_es.lat|floatformat:6}}</td>
  <td style="text-align:right">{{ent.tag_es.long|floatformat:6}}</td>
  <td style="text-align:right">{{ent.other_station}}</td>
  <td style="text-align:right">{{ent.tag_os.lat|floatformat:6}}</td>
  <td style="text-align:right">{{ent.tag_os.long|floatformat:6}}</td>
 </tr>
{% endfor %}
</table>

<p>But the Entrances - the objects in the troggle system - are not properly connected to the dataset which is the combined set of survex data. They are only linked - and only implicitly - by the tag name. The data in the table below is calculated directly from 
the assemblage of survex files, including fixed point files, and is probably 'correct'. 
<p>But which coordinate system are they in ? Read these three articles to find out:
<br>
<a href="/eastings">Troggle UTM data report</a><br>
<a href="/handbook/survey/lasers.htm">Geographical fixed points on Loser</a><br>
<a href="/handbook/survey/coord2.html">GPS and coordinate systems</a><br>
<a href="/handbook/survey/coord.htm">Basic Coordinate Systems</a>.

<p>This next table is of all the survex stations in troggle: i.e. only those survey stations which have been identified with an Entrance by manually editing the Entrance data.
<table cellpadding="6" cellspacing="8">
<tr><th>Survex Station</th><th>x</th><th>y</th><th>lat.</th><th>long.</th><th>Used on ent</th></tr>
{% for s in stations %}
<tr>
  <td style="text-align:left; width:240px"> {{s.name|safe}} </td>
  <td style="text-align:right; width:90px"> {{s.x|floatformat:2}} </td>
  <td style="text-align:right; width:90px"> {{s.y|floatformat:2}} </td>
  <td style="text-align:right; width:90px"> {{s.lat|floatformat:6}} </td>
  <td style="text-align:right; width:90px"> {{s.long|floatformat:6}} </td>
  <td style="text-align:right;" > {{s.entrance|safe}} </td>
</tr>
{% empty %}
  <td colspan="3"> NO STATION DATA - This is due to survex (cavern) failing on the entire dataset.
  <br>See <a href="/dataissues">DataIssues</a> 'survex' section . 
  <br>Resolve the survex errors and do a full databasereset import. 
  <br>You should look at the .log and .err files produced by survex in the :loser: repo folder first.
  <br>
  <br>Probably, the generaton of the .3d file has failed, so the .pos file is not generated.
  <br> Look for a message like this 'Failed to find /mnt/d/EXPO/loser/1623-and-1626-no-schoenberg-hs.3d so aborting generation of new .pos, using old one if present'
  </td>
{% endfor %}
</table>

{% endblock %}