Activity 5: Microclimate Geodatabase Construction for deployment to ArcPad

Introduction

This week the class was given the task of creating a geodatabase which will be used with ArcPad in the next week or so. This geodatabase is where we will store our points and information for a microclimate map here on campus. Create a geodatabase can a be a easy task if using ArcMap and ArcCatolog but if you want to do it correctly to make data analysis easier it becomes much more in-depth and difficult. This whole activity is in preparation for a future field activity, the better a this activity goes and the more time and attention to detail is used the easier the future field activity part of the exercise will be. One of the biggest parts of field work is the pre-planning,which is what this exercise focuses on. In part one we explain the reasoning behind a geodatabase and part two the actual construction of one.

Part 1

Before going out into to the field the first that needs to be done is preplanning to make sure you have the proper tools and equipment. Just going into the field with no preparation will never end well. A tool that we will be using in the field to create out microclimate map is a Juno GPS unit ( Figure 1). This unit has ArcMap on it which allows us to upload our geodatabase we created and directly edit and add data such as point, line and polygon features to the geodatabase.

Figure 1
This Trimble Juno GPS unit is what we will be using in the field to collect our data points. Using ArcMap on the Juno and importing our created geodatbases we will collect GPS points.

First before we can upload the geodatabase to the Juno unit we have to create the geodatabase. A geodatabase is a common data storage and management framework in connection with ArcGIS. It is basically a big storage bin for your GIS data where you can easily access and edit the data. The creation of a geodatabase that is designed specifically for a field task such a creating a microclimate map is a time intensive process which requires a lot of thought about what exactly you will be doing in the field and what data you will be collecting. Below you can see the steps that ESRI the creators of ArcGIS suggest when creating a geodatabase (Figure 2). As you can see there are many things to consider.

Figure 2
Suggested steps for database creation from ESRI. All of these should be considered when preplanning for a field mission and creating your geodatabase.

One of the most important aspects of geodatabase design are Domains. ArcHelp gives a very good definition of what these domains are. "Domains are rules that describe the legal values of a field type, providing a method for enforcing data integrity. Attribute domains are used to constrain the values allowed in any particular attribute for a table or feature class. If the features in a feature class or nonspatial objects in a table have been grouped into subtypes, different attribute domains can be assigned to each of the subtypes. A domain is a declaration of acceptable attribute values. Whenever a domain is associated with an attribute field, only the values within that domain are valid for the field. In other words, the field will not accept a value that is not in that domain". To sum up that definition, we use domains to limit what values can be entered for a certain feature which helps to keep the data accurate and cuts down on data entry errors. Take a temperature data set for example. When creating the domain you would set a temperature range of -20 to 100 degrees. If by accident you enter a value outside this range like 1,000 it will not accept the value and ask you to enter an new value. This helps keep the data in reasonable range eliminating outliers or very extreme values that will skew your data.

When creating domains you have a variety of different fields you can sign. These include: short integer, long integer, float, double, text, and date. Below is some explanation of these fields provided by ArcHelp (Figure 3).



Figure 3
These are a few of the field type options for domains. Short integer and float are typically the most popular options. They respectively  allow for either whole number values or fractional values to be entered. These two types as well as text will be used in this assignment. Text lets you enter words such as grass or asphalt for land cover values.

Part 2

For this second part of the exercise I will be showing you how to create a geodatabase and also set domains to customize the database for the specific field work task. There a multiple steps to this process. They are as follows:
1. Preplanning for geodatabase creation and field data collection
2. Creation of a new geodatabase
3.  Setting of domains based on preplanning info
4. Creation of the feature class that will be used to collect data
5. Import the project into ArcMap

Step one is all about thinking about the project at hand. We are creating a microclimate map. A microclimate is a small area that is different from the are surrounding it based on factors like temperature and humidity. These areas can be small like the courtyard area in Philips which is typically warmer and less windy than the areas around the outside of Phillips hall. A large microclimate would be a city where the temperature is usually more moderate and doesn't experience bitter cold like rural areas do.

In order to create a microclimate map many factors need to be taken into consideration. In our case will be looking at temperature (ground level and at 2 meter height), wind speed, wind direction, relative humidity, dew point, and land cover type. All this data will be collected here on the UWEC campus and from which we will create our microclimate map.

For steps 2- 4 I will walk you through step by step in the tutorial below.

Conclusion

Creating a geodatabase itself is not a very challenging task however, paying close attention to detail is the challenging part. If this is not done correctly work in the field will not be successful. This is all part of preplanning for a field mission. If everything has been planned out well before the field portion begins, data collection can and should go smoothly. We will see how well I planned ahead in the design of my geodatabase when we go out to collect data in the next couple of weeks.