I'm new to all this surveying and mapping.

I've got a centreline on survex and am currently drawing up the passage detail. Is there an easy way to overlay the centre line onto google earth or google maps?

Preferably if there is a free option, even better.

jess

One way would be to use Therion (a free download of a cave survey package). It does take some getting to know but it has an output option to export into .kml format (google earth format).

Hi there and welcome to the world of surveying.

Two things:

Firstly, there is a simple way of getting an overlay onto Google earth,, but not through Survex!

Therion will output .kml files, which are the appropriate ones directly. This does not mean that you have to do the job all over again as you can import your .3d file into Therion.

This is quite straightforward. The only glitch point is ensuring that your fixed point is in the correct co-ordinate type otherwise it won't appear in the right place on Google Earth.

Second point, [puts evangelical hat on] Obviously I do not know where you are working or what you have done, but I would hope that might take a look at the data repository at http://cave-registry.org.uk/ and consider adding your data to it. The idea behind this is to prevent future loss of data which has happened all too frequently in the past and has meant a lot of duplicate work has had to done these past few years. Please at least read the background stuff before dismissing it.

Learning to use Therion might be a bit too much investment of time if you're just using it to plot survey data.

You may be interested in trying to export the data and then use this very nice online service to visualise it:
http://www.gpsvisualizer.com/

The big problem will be getting it from a metric grid (survex) --> latitude + longitude.

If you're working with the OS Grid, this page might get you started:
http://www.movable-type.co.uk/scripts/latlong-gridref.html

Essentially if you have a fixed point on survex as (0,0) and then have your entrance GPS location, and calculate the local conversion between Northing Metres --> Lattitude & Easting Metres --> Longitude, then you can fudge it together in a spreadsheet.

jarvist said:

The big problem will be getting it from a metric grid (survex) --> latitude + longitude.
Essentially if you have a fixed point on survex as (0,0) and then have your entrance GPS location, and calculate the local conversion between Northing Metres --> Lattitude & Easting Metres --> Longitude, then you can fudge it together in a spreadsheet.

Click to expand...

Therion does it automatically. And to use data from Survex and generate a kml of surveying line is question of:

2 lines in thconfig file:

source xxxx.th - file with import of survex data
export map xxxx.kml


import of Survex data (http://therion.speleo.sk/samples.doc/40.html):

`import'
Description: Reads survey data in dierent formats (currently processed centreline in
*.3d, *.plt, *.xyz formats). Survey stations may be referenced in scraps etc. When
importing Survex' 3D le, stations are inserted in survey hierarchy, if there exists identical
hierarchy to that in 3D le.
Syntax: import <file-name> [OPTIONS]
Context: survey / all32
Options:
filter <prefix> . if specied, only stations with given prex and shots between them will be imported. Prex will be removed from station names.
surveys (create)/use/ignore . species how to import survey structure (works only with .3d les).
create . split stations into subsurveys, if subsurveys do not exist, create them
use . split stations into existing subsurveys
ignore . do not split stations into sub-surveys
 cs <coordinate system> . coordinate system for stations with xed coordinates
 calibrate [<x> <y> <z> <X> <Y> <Z>] . coordinates in the imported le are shifted
from lower-case coordinates to upper-case coordinates.

As has been mentioned above you really need to convert your survey points to Latitude and Longitude. As an alternative to the above suggestions I have developed some software to do this and assuming you don't have masses of data and have a Grid Ref for the entrance (or some point on the survey) I wouldn't mind converting your centre line data for you. I don't think getting from that to KML would be particularly difficult.

I'm not sure what you are expecting but it may be worth mentioning that whilst KML data can be imported into google earth and whilst there is nothing wrong with google mapping, bing maps allow you to see the data on an OS Map background (e.g. http://chris-h.me.uk/cavemapping/) although getting the data on line takes a little more doing.

TheBitterEnd said:

As has been mentioned above you really need to convert your survey points to Latitude and Longitude.

Click to expand...

& has also been mentioned, Therion does this automatically.

TheBitterEnd said:

I'm not sure what you are expecting but it may be worth mentioning that whilst KML data can be imported into google earth and whilst there is nothing wrong with google mapping, bing maps allow you to see the data on an OS Map background (e.g. http://chris-h.me.uk/cavemapping/) although getting the data on line takes a little more doing.

Click to expand...

If you do decide to use Therion, you can download a surface overlay & make a three dimensional model see this link You can drape OS map data (some is open source & thus publishable) or aerial photography over the surface & the whole thing gets very wizzy looking. For example this file which opens in Therion's viewer 'lox' shows the extent of the caves in the Cheddar Catchment as surveyed to the end of 2011.

If even an idiot like me can build these files, then anyone can.

graham said:

& has also been mentioned, Therion does this automatically.

Click to expand...

Do you have a problem with people learning / figuring out how to do this themselves? Or of volunteering their time to convert someone else's dataset?

jarvist said:

graham said:

& has also been mentioned, Therion does this automatically.

Click to expand...

Do you have a problem with people learning / figuring out how to do this themselves? Or of volunteering their time to convert someone else's dataset?

Click to expand...

No.

Do you have a problem with people pointing out short cuts?

Sheesh!

Now, Now Play nice!

I printed off the Therion manual yesterday and have started to have a look at the relevant bits. Think i'm going to need a lot of time to get my head around it, but i'll get there eventually.

Sadly this survey wasn't for a cave at all, but a culvert running under a grade 1 listed house in Dorset that i used to work on. They let me go in and survey it to confirm my theory that there were other culverts branch in and off the main section and thats why the water levels appeared weird where we had monitoring equipment.

I've got a old colleague who's a GIS wizz sorting the survey now, but i would still like to learn as i now have 3 mine surveys which i need to finish drawing up which i could do with showing people.

Any takers for someone doing a training course 'idiots guide to Therion Mapping' or bringing a laptop and showing me next time you are at the TSG. Any takers drop me an email; secretary@tsgcaving.com

There is another way to do this without getting your hands dirty with Therion. But you'd have to get your hands dirty with Photoshop instead

Basically output your survex file as an EPS, open your EPS in Photoshop, change any black lines to white, save your file as a transparent PNG.

Then in Google Earth, use the 'Add Image Overlay' and import your PNG, and adjust to fit with the green grid lines. Hey presto!

Purists will no doubt be aghast that the thing ain't fixed with coordinates and whatnot, but if you want a rough and ready but reasonably accurate visual, it can be done in 5 minutes.

If you know your Photoshop you might thicken up the centreline by one or two pixels, because otherwise it might be pretty feint if you zoom out in GE.

I have no idea what colours or line thicknesses the Therion kml produces?...... but with Photoshop you can make it any colour you like to stand out against the topography

Sorry to resurrect an old thread but my problem is slightly related.
Over the last few weeks I have been teaching myself Therion and have managed to create a more than passable survey(even if I do say so myself).
I would now like to overlay the survey into Google earth to see how underground features relate to surface features. I am having a problem getting Therion to output a KML file.
I have converted my British grid reference using the Movable Type Scripts tool and written the fix into my text file. However when I compile the project I get an error message telling me the survey is not georeferenced.
What am I doing wrong?
Any help will be appreciated.
Tim

Tim

Do you have a line telling Therion what co-ordinate system you are using? And what is the Movable Type Scripts tool?

The .th file that contains a known point should both contain a line such as:

cs OSGB:ST

Which tells the program that the co-ordinate system you are using is Ordnance Survey GB sub area ST (that would be MENDIP).

also you need a fixed station, usually an entrance or just outside it. So if your fixed point is station 1 you would have the line:

fix 1 [easting] [northing] [altitude]

with just the figures, not the square brackets.

With these in place and this line in your thconfig file:

export map -proj plan -fmt kml  -o [filename].kml

Good luck

Graham
Thank you problem solved. I was missing the cs OSGB line.
The movable type tool is the one mentioned by Jarvist in reply 3

Tim

Dropper said:

Graham
Thank you problem solved. I was missing the cs OSGB line.
The movable type tool is the one mentioned by Jarvist in reply 3

Tim

Click to expand...

Ah, right. Didn't think it was part of Therion.

I believe that Therion now supports every named (ie ST) square of OSGB, though the correct one does need to be specified. It's then important to start the co-ordinates at the right number. Cannot give a rule on that, only know how my own files work. If you get it wrong you know immediately, as the cave moves a long way from where it should be.

May I ask what the cave is?

It is a stone mine on the Cotswolds. I am not in a position at the moment to say where but hopefully in the future the information should be able to be made public.

darklord said:

I have no idea what colours or line thicknesses the Therion kml produces?...... but with Photoshop you can make it any colour you like to stand out against the topography

Click to expand...

Open kml file in plain text editor and change what you want.

Jess (aka real bat girl) said:

I printed off the Therion manual yesterday and have started to have a look at the relevant bits. Think i'm going to need a lot of time to get my head around it, but i'll get there eventually.

Click to expand...

Hi Jess, it is not the best idea to start with TherionBook. It is Reference Guide, not the user manual. There is quite huge wiki section on Therion pages. Check it first.

TherionBook is very useful if you want to know which parameters are possible to add to a particular symbol.

darklord said:

I have no idea what colours or line thicknesses the Therion kml produces?

Click to expand...

Check: https://developers.google.com/kml/documentation/kmlreference#linestyle

Beginning of .kml file - you may see that there is no any problem to change the color or the width (in pixels) of a line:

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.0">
<Document>
<name>Therion KML export</name>
<description>Therion KML export.</description>
<Placemark>
<Style>
<LineStyle>
<color>ffffff00</color>
<width>1</width>
</LineStyle>
</Style>
<MultiGeometry>
<LineString>
<coordinates>
20.30658333333331,42.73681666666666,542.00000000000000
20.30652108870869,42.73676463663531,540.65551443581501
20.30649281451217,42.73669816116888,544.29592737869643
20.30649793222162,42.73670275349230,541.69536562090582
20.30648120748704,42.73668175877027,539.55553507033369
20.30647240843654,42.73669419354091,538.71449556740254
20.30650900118791,42.73668592988295,537.21550191250810
20.30650403444189,42.73662209459315,539.28911517621509
20.30651963285312,42.73662280137408,538.42817890376455
20.30652804853202,42.73660602845630,538.49405824322253
20.30654610058526,42.73659459765038,540.09421386700546
</coordinates>
</LineString>

sluka said:

darklord said:

I have no idea what colours or line thicknesses the Therion kml produces?

Click to expand...

Check: https://developers.google.com/kml/documentation/kmlreference#linestyle

Beginning of .kml file - you may see that there is no any problem to change the color or the width (in pixels) of a line:

<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.0">
<Document>
<name>Therion KML export</name>
<description>Therion KML export.</description>
<Placemark>
<Style>
<LineStyle>
<color>ffffff00</color>
<width>1</width>
</LineStyle>
</Style>
<MultiGeometry>
<LineString>
<coordinates>
20.30658333333331,42.73681666666666,542.00000000000000
20.30652108870869,42.73676463663531,540.65551443581501
20.30649281451217,42.73669816116888,544.29592737869643
20.30649793222162,42.73670275349230,541.69536562090582
20.30648120748704,42.73668175877027,539.55553507033369
20.30647240843654,42.73669419354091,538.71449556740254
20.30650900118791,42.73668592988295,537.21550191250810
20.30650403444189,42.73662209459315,539.28911517621509
20.30651963285312,42.73662280137408,538.42817890376455
20.30652804853202,42.73660602845630,538.49405824322253
20.30654610058526,42.73659459765038,540.09421386700546
</coordinates>
</LineString>

Click to expand...

You can change the line colour and thickness in Google Earth after you've created the kml. Just look at the properties and click on the 'Style, Colour' tab.