Sandbox Elevation Model

Introduction

The first assignment of the class consisted of the construction of a fictitious landscape inside the Phillips's Courtdyard Garden Planter Boxes to model a real surface. It also included the later survey of coordinate points, including elevation (x,y,z), to transfer the elevation model to ArcGIS.

However, instead of having a step-by-step tutorial with all the procedures to complete the tasks, we were suppose to use our creativity, so we had freedom to decide how we would do this. 

The exercise worked as a miniature of a real fieldtrip, where you need to plan how you'll obtain your data, which tools you'll use, how the outside conditions may interferer in your collection and find out how you'll deal with that.

It will be possible to learn how to improve the data collection in a real-world situation, by the evaluation and experience obtained in this exercise.

Figure 1 - Data Collection

Methods

Firstly, it was necessary to plan how the data collection would be done. In a preliminar meeting, the group decided some specifications of the coordinates, such as where the origin would be located and which level of detail we would use, or in other words, how big the collection interval would be. Then, it was decided to create imaginary 6x6 inches boxes with the strings and collect the central point of these boxes. This model was drawn in a notebook where the elevation points would be written on.

For that, a big ruler, measuring tape, string and a knife were necessary. We went outside on January 31 afternoon, and then we started creating the landscape with the snow available. We created hills, mountains, rivers and plains. With the measuring tape and the knife, we marked the 6 inches interval points from the origin (Figure 1).

We tried to tie the strings in these marks, however, the tape we got for that didn't work as we expected, so the strings were not getting fixed in the wood.

Then, we took advantage of the big ruler we had, which could work as the string, and we positioned it in each two points of the planter box, so with the measuring tape, we could collect the points every 6 inches inside of that imaginary box.

After the collection, the data were typed in excel, following the idea of the boxes. With the data, it was possible to calculate the x and y coordinates. The numbers obtained for the elevation were multiplied by -1 to reflect the idea that the top of the planter box was the mean sea level.

In total, 98 points were collected, as it's possible to see in the Figure 2. The next step is to input this coordinates in a single table and import to ArcGIS, which will be done in the next exercise.

Discussion

This exercise was really productive considering the learning aspects. Since we had to figure out by ourselves the procedures, we had the opportunity to try different methods and notice the ones that would work better. The self-analysis is crucial in this step, because after the work was done, we had a lot of lessons.

The first big lesson was to be really aware not only of the outside conditions, but of the period of time you're going to be in these conditions. At the time we were collecting the data, it was -15ºC, which is an acceptable temperature to walk from a building to another. However, the collection last much longer than that, compromising our work. Thus, in the next projects, a good strategy is to be outside for a while to test how these conditions might compromise your work or not, and then, depending on how it's, to adapt - in this case with more layers and gloves - to avoid the loss of productivity.

Another important lesson is to plan ahead and leave everything prepared before you go to the field. That's more important when the outside conditions are challenging, but it's still truth in any occasion. We need to cut the string pieces with the right size for the box, but it was a lot of strings and we did that outside. Considering it was extremely cold, it would be better if we have got the right measurement and cut all the strings inside. So, it's really important to plan carefully and think about details like that, sometimes they're small and won't compromise the project, but in more challenging situations, it can be a real problem.

However, these obstacles we faced were seen by us as challenges that we felt happy to overcome and learn with them. It was a good experience to work as a connected group, despite the division of tasks. Also, the freedom of ways to collect the data made us more flexible. Hence, when a unforeseen problem happened - as the tape not fixing the strings - we could quickly improvise a different way that would work as much as the other. This allowed us to exercise our creativity and learn how to deal better with the unexpected things that happen in the field.

Conclusion

The exercise should be considered successful in its objectives. We were able to plan ahead and understand better which techniques we could use to collect data at the field. By executing, the challenges worked as a way to teach us different ways to deal with it and still get the necessary results. For last, by registering all the work in a report, it was possible to evaluate the experience as a whole and to learn better ways to collect the data in future field-works.