TECHNICAL FORUMS > Surveying

Therion - create centerline svg with stations as objects?

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rhyst:
Hello,

Currently redrawing old surveys in Therion. The workflow is:

1) Export centerline to svg
2) Open in inkscape using therion plugins
3) Using the svg as a trace mark all the stations as station objects
4) Draw the passage around the centerline
5) Save as th2

Step 3 seems unnecessary. Is there a way to export a centerline svg where the stations are either actual objects (like the ones used by the therion inkscape plugin). It seems like all the information is there but I have no idea how to do that using therion.

The centerline export config looks like this:

source passage.th
layout test
 scale 1 500
 endlayout
export map -projection plan -o passage.svg -layout test -layout-debug station-names

Thanks for any help!

alastairgott:
it depends how "quick and dirty" you want it.

The other week I quickly sketched around the nettle pot passages so I could export to kml and overlay on google maps(/earth). I expect this may be one of your intended outcomes.

My example from District 9, Marniosa in spain is a survey which was made using trad techniques and the centreline printed from survex and drawn "out in the field (rather than uk)" before the bar. Therion would have coped with the original sketches and warped the image to fit the survey points. but it's far easier to redraw using the survex as a skeleton.

alastairgott:
If you are doing part old surveys, then it's important to use the Scalebar, the red arrow in the nettle pot example (copyright admission it's from Caves of the Peak district).

in this case I had to use trig to work out the "real scale points", I guessed nettle sits on a NW-SE heading and then had to amend the scalebar points, as therion needs to know where the ends of the scalebar are in relation to W-E.

in this case it's -35.35, 35.35||||| 35.35, -35.35
or 50sin(45)

Steve Clark:
I'm possibly misunderstanding.

Do you have the original centreline survey data ?

What format do you have the old survey drawing in? (something drawn by hand & scanned or a vector/coreldraw/CAD type format?)

alastairgott:
Probably important to also note that I've skipped the SVG step and just gone straight for JPG as a background image, as in the Nettlepot example, see the background images tab.

The use of the red scalebar arrow is not necessary in the district9 example, as there is a full centreline driving the image and giving it orientation and scale. however in the Nettlepot example it is necessary, as it only has one point defined (the entrance) and the rest of the survey just swings about this one point (hence the old rule that all scraps must have at least one point).

There is a third method of driving survey data in therion (there's probably more). but that is to use an existing survex (.3d) model. This is not a viable option if you want to switch between using the .3d data for some subsurveys and a full centreline in others to overlay the image on Googlemaps, as .3d files come with their own coordinate system.

For this reason in the Marniosa project I've been working on I've got two .th files pulling it together.
 see Marniosamaster.th and compare it to marniosaGPS.th
with specific reference to the centreline
--- Quote ---centreline
cs  UTM30N
station 1.0@Silvestre.SilvestreMaster "Silvestre" entrance
fix 1.0@Silvestre.SilvestreMaster 0360751 4789715 1130
equate 1944@Electronica.SilvestreMaster 0@marniosa_upstream_3
--- End quote ---


source http://cave-registry.org.uk/svn/Andara/Tresviso/Marniosa/therion/


Below is an example of how I've driven a therion file set with the .3d file.


I've included the .3d file by using import MarniosaReport2019.3d -survey use

in the top left hand corner, then I've used the "aven" application to match up where I want the points, notice here I've only included the entrance. Bottom left in the grey bar it says -name Marniosa.entrance_pda.1


this is inputted in topright box "points" under the options header -name ….

this relates directly to the .3d file top left, except the name marniosareport2019 has been chopped off. remember to use the scale bar in this, as the background image will be any old orientation you've scanned it in.

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