Author Topic: Anyone know how to overlay servex centrelines onto Google earth?  (Read 4612 times)

Offline Jess (aka real bat girl)

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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

Offline spanners

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #1 on: May 15, 2012, 02:33:33 pm »
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).

Offline graham

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #2 on: May 15, 2012, 02:37:10 pm »
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.
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Offline jarvist

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #3 on: May 15, 2012, 03:15:59 pm »
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.

Offline sluka

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #4 on: May 15, 2012, 03:40:17 pm »
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.

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 di erent 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.

Offline TheBitterEnd

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #5 on: May 15, 2012, 07:10:01 pm »
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.
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Offline graham

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #6 on: May 15, 2012, 08:01:05 pm »
As has been mentioned above you really need to convert your survey points to Latitude and Longitude.
& has also been mentioned, Therion does this automatically.

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.

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.
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Offline jarvist

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #7 on: May 15, 2012, 11:06:36 pm »
& has also been mentioned, Therion does this automatically.

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?

Offline graham

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #8 on: May 16, 2012, 07:49:29 am »
& has also been mentioned, Therion does this automatically.

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?

No.

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

Sheesh!
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Offline Jess (aka real bat girl)

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #9 on: May 16, 2012, 12:01:58 pm »
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

Offline darklord

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #10 on: October 08, 2012, 07:42:23 pm »
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 :)

Offline Dropper

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #11 on: March 23, 2014, 07:40:48 pm »
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
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Offline graham

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #12 on: March 23, 2014, 08:45:43 pm »
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
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Offline Dropper

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #13 on: March 23, 2014, 09:31:06 pm »
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
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Offline graham

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #14 on: March 23, 2014, 09:41:43 pm »
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

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?
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Offline Dropper

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #15 on: March 23, 2014, 10:00:51 pm »
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.
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Offline sluka

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #16 on: March 24, 2014, 08:09:49 am »
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 :)

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

Offline sluka

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #17 on: March 24, 2014, 08:14:07 am »
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.

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.

Offline sluka

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #18 on: March 25, 2014, 05:05:17 pm »
I have no idea what colours or line thicknesses the Therion kml produces?
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>

Offline mulucaver

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #19 on: March 26, 2014, 07:51:34 am »
I have no idea what colours or line thicknesses the Therion kml produces?
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>

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.
Dave Clucas
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One Cave at a Time

Offline cavermark

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #20 on: March 26, 2014, 09:38:52 pm »
The recent digital surveying course organised by the cave surveying group covered some of this - I'd recommend anyone wanting to get to grips with this stuff to attend a future one, if they can, for hands on non condescending advice.  (but of course this forum is good too).

Offline alasdair neill

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Re: Anyone know how to overlay servex centrelines onto Google earth?
« Reply #21 on: April 05, 2014, 10:02:34 am »
A method I have used where I have also wanted to show the centreline or complete survey on OS maps of various dates is using a drawing programme & importing the maps (I use oldmaps as they are corrected to grid north & scale for pre national grid editions) & googlearth as screen prints. Bear in mind googleearth needs to be corrected from true north to grid north, & can then be scaled to fit to the maps. The survex data can be imported as a DFX file, but will need putting at the right scale & location. This may seem long winded but works for me.