Walls Questions

[rchrds]

Okay- a few walls questions!

1. is there a forum somewhere where people are actually discussing walls? I have a lot of questions.

2. Can someone provide an example of a #units flag that would allow for the use of depth (as in diving) instead of vertical angle? For example, normally I use
#units feet Order=DAV
But what if I have a depth (expressed in positive numbers) how do I change my #units statement? The manual discusses it obliquely, but I dont get it.

3. If I describe an absolute surface (i.e. GPS) location in the project properties, how does it know what point to assign it to? Does this supplant any #fix commands put in lower branches, or Should I be leaving the properties geolocation blank and using a #fix statement where I can specify which station is my datum?

4. Where can I find a description of how to add my sketches to the line plot? I know I've seen it done by folks who use this program all the time, but I cant find it anywhere in the online help. I haven't finished the manual yet. (Sorry, RTFM right?)

Thanks-
Feel free to reply to my email-
Jason
rchrds@charter.net

[Roppelcaver]

I am not the world's greatest expert on Walls, but have probably used it about as much as anyone. I will try.

Your questions:

1. Would be nice, although David (the author) has always been helpful with questions.

2: I would have to look as I do not do "depth" that often. I just have to dust off the memories. I looked in my data and see that I used Instrument/Target heights to render the desired affect. From the help file:

"Instrument/Target Heights
To handle a large stash of existing survey data, the SRV format supports optional fourth and fifth measurements on compass and tape (CT) data lines. Walls will interpret these as an instrument height above marked station followed (optionally) by a target height above marked station. If the taping method is instrument-to-target (the default assumption), the effect of these heights is equivalent to adding their difference (IH minus TH) to the computed elevation of the TO station with respect to the FROM station. Note that the #Units directive's INCH vertical adjustment is not necessarily related to these measurements; it is independently applied to all CT data, regardless of whether or not explicit height above station measurements are present.

Earlier versions of this program did not support the four different taping methods. When instrument/target height measurements were encountered, the taping method was naturally assumed to be along the line of sight -- that is, instrument-to-target instead of station-to-station. This has always seemed to me the only logical method to adopt since instrument/target height measurements are necessary only when the line between marked stations is either obstructed or not easily accessible. What finally tilted the balance in favor of support was the requirement to handle underwater surveys, where station-to-station taping is indeed the proper way to represent bearings, taped distances, and depth gauge measurements. Here, depth measurements are treated as if they were IT heights.

3. The Geographic Reference for the Project is what I think you are referring to (your GPS location). This allows the program to apply proper corrections (i.e., UTM versus True north coordinates). Your other "fixed" coordinates are not affected otherwise (although they should be in the same local region as your geographic reference, of course). So, you should have the geo reference specified and whatever fixed stations (in feet, meters, Lat/long, etc.) you want.

4. RTFM. I don't use the roundtripping myself, but hear it works just fine. Others may weigh in.

Later.

[robcountess]

#units feet order=DA

vector line should be in format: From|To|Dist|Azi|Depth where Depth is the change in depth from the "From" station to the "To" station

Alternatively you can convert your depth data to inclinations in Excel. Just use the following formula =asin((Dt-Df)/T)*180/pi(), where Df is the absolute depth (ie guage reading) of the From station, Dt is the absolute depth of the To station, and T is the tape reading.

[Jeff Bartlett]

4: what program are you planning on using for drawing your map?

[Spike]

In response to:

1. This seems to be the best forum for Walls questions. Many of use us Walls exclusively and others have at least played with Walls.

2. I assume that the tape, or dive line is not horizontal, but at and inclination. If so I think Rob is tight.

3. In order to get Walls to spit out UTM coords for each station correctly and adjusted for declination using the #date flag, you must fill out the geolocation information in the properties dialoge, this is the only way for Walls to know which UTM zone you are in. You also need to #fix a station in order for Walls to know where in the UTM zone the cave is. Otherwise the default is for a station to be at the origin of the zone and (station A1 is at 0x 0y 0z). You don't have to work in a UTM projection, but it does make things a little nicer if you are going to make shape files.

Spike

[rchrds]

#units feet order=DA

vector line should be in format: From|To|Dist|Azi|Depth where Depth is the change in depth from the "From" station to the "To" station

Alternatively you can convert your depth data to inclinations in Excel. Just use the following formula =asin((Dt-Df)/T)*180/pi(), where Df is the absolute depth (ie guage reading) of the From station, Dt is the absolute depth of the To station, and T is the tape reading.

Damn. This is the same way that Winkarst does it, and it is hopeless. Once the data is converted to this format, it is very difficult to go back into the data and look for depths- the numbers get very confusing very quickly inputting a change in depth instead of an actual depth- particularly if you have a large number of readings. Short of adding a note to every shot that describes the actual depth, it is very easy to lose track of the actual depth at a station and then have to go back and figure depths at Ts, etc. Particularly if years later all you have is the digital file. Sigh.

Thanks for the description of how to do it, however.

Jason

[Aaron Addison]

I'm going from memory here, but could you not get absolute depths simply by:

1. complie survey
2. Goto the Segements tab
3. Click Details/Rpts. button in upper right
4. Click coordiantes button.

I think that this should give you the XYZ of every station.

Aaron

[robcountess]

you can alway keep the raw depth data in the vector line as a comment

[Spike]

When looking at a line plot in Walls' map display you can have Walls plot elevations at each station.

Spike