USING WALLS: ENTERING DIVE SURVEY
This is part one of a long-term series which will cover many features of the cave survey application, Walls Project Editor.
Introduction
This tutorial will cover the basic steps of creating an underwater cave survey project and entering dive survey using the application, Walls Project Editor.
Walls Tutorial:
ENTERING DIVE SURVEY
by Rory O’Keefe, December 28, 2020
Section 1: Download and install Walls Project Editor.
Download Walls Project Editor from the Texas Speleological Survey website, here.
Install the application.
Section 2: Create a new project.
The Walls Project Editor isn't just a tool to view your survey data, it allows you to create a regional database (by UTM zone) that helps to organize your data for years to come. I recommend creating a database-style project file to manage all of your data rather than a completely new project for each cave.
As your work continues, you can create books within the main project to further organize sub-regions by cave system or general location (Example: Country, state, region, cave system). Note that the Walls user manual recommends using a reference position no farther than 40 kilometers from the cave entrance when calculating for magnetic declination.
Follow the steps below to create your first Walls Project File:
Open Walls Project Editor.
In the top menu bar, go to File > New Project...
A dialog box will pop up to create a new project file.
Choose a location to permanently save and manage your survey data.
This project file can be used to maintain all of your survey data from multiple projects within the same region, or it can be created for a single specific cave system.
Tip: Set your project folder to be automatically backed-up to a cloud storage service.
Save your project – a Properties box will automatically appear.
Section 3: Project Properties.
Part 1: The Properties Box.
Choose your Review Units (feet or meters).
The Review Units are just the units that your compiled data will be presented as.
You can still enter data using feet, meters, or a combination of both, regardless of what you select as your Review Units.
Create a Title for your project.
The Title is the display name of the project in your project-tree.
Remember: This project file can be used for multiple caves within the same UTM Zone, or a single cave project. So, choose the project name accordingly.
Create a Name for your project file.
The Name is the file name of the WPJ file saved to your hard drive.
File names are limited to 8 characters.
Tip: File names and titles are easily changed by opening the Properties box of a selected book or file.
Next, select the Geographical Reference tab.
Part 2: Geographical Reference Tab.
This is where you will set the coordinates/UTM Zone for your project.
Note that the coordinates you set here are to specify a general area that is primarily used by Walls for calculating the magnetic declination. Individual cave entrance coordinates will be added to the survey data for each specific cave location within the general project area.
As your survey project grows, you may eventually need to create new books within your project-tree to specify different regions that are more than 40 kilometers apart. View the “Properties: Geographical Reference Page,” section of the Walls Project Editor user manual for more information on this subject.
Follow the steps below to assign reference coordinates to a project:
Working in the Geographical Reference tab, uncheck the Unspecified box. Additional options will then become available.
In the Declinations column, select Derive from #DATE.
This will allow Walls to accommodate for the magnetic declination between magnetic north and the north pole as it changes over time using the date of your survey data.
In the Coordinates column, select UTM/UPS grid-relative.
This will allow Walls to present your compiled data using grid north instead of true north.
It is also required to export your data as a shapefile which can then be viewed in a geobrowser or GIS program such as Google Earth.
Note: Grid north is a way of representing true north of the round earth on a flat map. The difference is minimal for cave survey purposes however the box must still be selected to export shapefiles.
Next, select the Change... box to open the Reference dialog box which is where you will enter the actual coordinates of your project area.
Part 3: The Reference Box.
Working in the Reference box, enter the date that your coordinates were recorded, followed by the elevation and actual coordinates of your project area.
You can change the lat/long format by selecting dms, dm, or d, under the Fmt column.
I am using the UTM coordinates: 462998E, 2249232N Zone 16N
Select the correct Datum used by your GPS device.
Most devices will be set to WGS 1984 (WGS84).
To finish, select Accept in the Reference box, and OK in the Properties box.
View the image below for a fullscreen summary of Section 3: Project Properties.
Section 4: Adding books to organize your project-tree.
Add books (or folders) to your project-tree to organize individual data files for a specific cave.
Feel free to repeat these steps to create as many books as you require to organize your project. Note that for caves outside of the project's UTM Zone, you should create a new project.
Select New Item in the project tree window - a New Item box will appear.
Under the Type column, select Book.
Choose the review units, create a title, and choose a file name as done in Section 3: Part 1, Steps 1-3.
The new book will automatically inherit the geographical reference location you set when creating the project file. Leave this set to Inherited if your survey data is within 40 kilometers of this location.
Note: If the book you are creating is for a cave located more than 40 kilometers away from the Geographical Reference coordinates you used to create your project file in Section 3, you should navigate to the Geographical Reference tab and uncheck the inherited setting. Next, follow the steps from Section 3: Parts 2-3, to assign a new set of reference coordinates to this new book.
Remember: The geographical reference coordinates are used for determining the magnetic declination of an area, so, for example, if I was creating a new book for Tulum, Mexico, I could use coordinates taken off of Google Maps from the middle of Tulum as my Geographical Reference coordinates.
Section 5: Creating a survey file.
Select the book you created in Section 4, and then select New Item in the project-tree window. A new Item box will appear.
Under the Type column, select Survey file.
This is to create a survey file that will be used to enter your survey data for this specific cave.
Choose the review units, create a title, and file name as done in Section 3: Part 1, Steps 1-3, then select OK.
The new file will automatically inherit the geographical reference location you set for the book it is located in. As a reminder, the actual cave entrance coordinates will be entered into the survey file.
Section 6: Setting up your survey file.
Part 1: The Survey Text-Editor.
Double-click the new survey file you created in Section 4. This will open up the Survey Text-Editor.
The Survey Text Editor is a text-based method of entering your survey data.
There are two main advantages to this. First, the survey data can be typed almost exactly as it is in your survey slate or field-book; Second, it is a non-proprietary format that can be safely archived and interpreted for many years to come.
The disadvantage of this long-term flexibility is that the text-editor creates a learning curve for new users.
Part 2: Header Comments.
It is important to first add some basic information to your survey file, such as the cave name, surveyed section, and surveyor's name.
This information is useful knowledge, but it is not considered to be data. For this reason, it will be prefixed as a comment using a semi-colon (;).
In the text-editor, a semi-colon prefix (;) is used to type a comment. Comments are not used as data and exist only for additional information you would like to include in the survey file.
For example, you could type the following at the top of your survey file:
;Cave: Nohoch Nah Chich
;Section: Main Entrance
;Surveyed by: Rory O'Keefe
Note: Press the Enter key once to create a new column on the same line, and twice to create a new row.
Part 3: Header Directives.
It is also important to include information such as the date, units, GPS location, and the order of your data (is it distance/azimuth/depth or azimuth/distance/depth?).
Because this information can all be used as data, it will be entered differently than the comments above.
In the text-editor, a pound symbol (#) is used to type a directive. Directives are used to tell the program that the following information is data, or formatting commands, etc.
For example, you would type the following for a basic, metric dive survey:
#Date 2019-01-28
#Units Meters Order=DA Tape=SS
#Fix NH1 0457852 2244569 8
For dive survey using feet, you would type the following:
#Date 2019-01-28
#Units Feet Order=DA Tape=SS
#Fix NH1 0457852m 2244569m 8m
Note: An m, indicating meters is typed after the UTM coordinates in the above case so that the coordinates are not measured in feet.
The Walls Project Editor user manual covers the reasoning behind the above directives in detail, but there are a few things worth explaining:
#Date directive:
Uses a format of YYYY-MM-DD.
#Units Meters or Feet directive:
Indicates that all of the following data is entered using meters or feet.
Order=DA Tape=SS directive:
Indicates that you will enter your station-to-station survey data in the following order: Distance, Azimuth, From-Depth, To-Depth.
For non-underwater cave survey, change the Order=DA Tape=SS directive to Order=DAV which means distance, azimuth, vertical (inclination).
#Fix <station name> <easting measurement> <northing measurement> <up> directive:
Indicates the UTM coordinates of the cave.
So, the NH1 in the above example is the station name that the coordinates were taken from. The 0457852 represents the Easting measurement, 2244569 represents the Northing measurement, and 8 represents the elevation of the station.
Part 4: Add column titles to help yourself organize data.
The following titles are entered as comments, meaning that Walls will not use them as actual titles that define what the numbers mean – they are simply useful for demonstration / organization purposes.
As already specified in the header directives, the order of your data, from left-to-right, will be:
From-Station Name
To-Station Name
Distance
Azimuth
From-Depth
To-Depth
Comments
Note: Press the Enter key once after each title to create a new column in the text-editor.
So, I like to enter a comment header as shown in the following image:
Section 7: Enter the survey data.
Use the below image to type in the survey data as shown.
I have intentionally given you the numbers as an image to keep this step realistic.
You can not copy & paste data from your survey slate, and data-entry typos are the most frequent cause of survey errors! So, check your work and look for typos!
While entering data, you may notice that Walls has an auto-sequencing feature for the station names. Once you type two consecutive station names, pressing enter should create a new line with the next set of station names.
Proceed to the next step to compile and save your file.
Compile the data by selecting Compile, located at the top left of the project-tree window.
A review dialog box will automatically appear showing your line survey if no errors are found.
Compiling your data will automatically save your survey file.
Section 8: Review your map.
The Review dialog box has numerous features that will be covered in future tutorials. One of its main functions, however, is to display your compiled data as a line plot.
Working in the Map tab of the Review dialog box, check the options for Grid, Label, and Mark.
The Label and Mark options will add station names and symbols at each station on your displayed map. This is useful when looking for a station name to attach future surveys to your existing survey.
Select Grid to edit the grid interval to your preference by changing the “East interval (m)” number under the Plans column.
I set the East interval (m) to 2 for a 2m x 2m grid.
Select Display Map to view your map.
Right-clicking on the map enables the Hand Tool which allows you to quickly scroll in all directions.
Zoom in and out using the mouse wheel.
Note: The default map view in Walls is rotated 90 degrees. You can change this to 0 by clicking the Rotate button under the Preview Map column. This Rotate button is highlighted in Section 10.
Section 9: Attach a second survey file.
Repeat the steps from Sections 5 - 7 to create and set up a new survey file.
Remember: the item Title is the title of your file in the project-tree. The Item Name is the file name of the SRV file which is saved to your hard drive.
You can copy & paste the header information from your first file into the new file to avoid typing everything again - don’t forget to update the comment information and date of the new survey file.
You can delete the #Fix directive in the new file if the survey will connect to a station from the previous survey.
Enter the new data as shown in the image below.
To attach the new survey to the previous survey, give the connecting stations the same name.
In this case, the connecting station is NH6.
Because of this, it is very important to use unique station names unless you actually want the two stations to be connected. An accidental repeat station name will connect to its counterpart when your complete project is compiled, even if the data is in two entirely different cave systems.
Select Compile to view your new map.
The project-tree gives you the option of viewing a compiled map of an individual survey file, each book, or the full database.
To compile a complete cave, or “book,” click on the specific book in the project-tree and select compile.
Section 10: Navigate the Review dialog box.
The Walls Project Editor has numerous features beyond storing and viewing survey data. Compile a project to open the Review dialog box and read through the image below as an introduction to some of these features.
Spend some time getting to know the program and play around with changing the map format, colors, and line types under the Segments tab.
Conclusion
Walls admittedly has a learning curve, but it is an excellent tool for managing large amounts of data, archiving, and cave mapping. It is my personal program of choice for working with survey data and I can say through experience that it offers the necessary features to take you straight through to a finished map.
It is also worth noting that Walls includes an extremely thorough user manual with a well-indexed search function.
View the image below for instructions on how to access the Walls manual:
Future tutorials using the Walls Project Editor will include the following:
Creating circuits and viewing loop-closure accuracy.
Adding LRUD dimensions to survey data.
Printing surveys for underwater sketching.
Exporting SVG files to Adobe Illustrator for drafting.
Roundtripping SVG files to update drafted maps with additional survey.
Exporting line surveys as shapefiles to be viewed in Google Earth.
Using Mnemo Bridge to quickly add Mnemo data into Walls.