GIS 6105 Module 6 - Interpolation

For the final map deliverable, I simply modified the map from Module 5 to create a sense of continuity between the two sequential lab assignments. The final map deliverable is displayed below:

The most challenging aspect of this assignment was truly understanding the structure of the SQL queries and what was being accomplished upon their execution; I discovered that the ESRI documentation on IDW provided some useful insight, as well as spending some time examining the calculations that were being solved within the query. This assignment was not the most challenging, but I appreciated using IDW interpolation on a vector dataset, as it is much more commonly used while working with raster datasets.

Souces:

ESRI. [2025]. How Inverse Distance Weighted Interpolation Works. Environmental Systems Research Institute. How inverse distance weighted interpolation works—ArcGIS Pro | Documentation.

GIS 6105 Module 5 - Tessellations

[Obe and Hzu, 2021] define tessellation as the process of 'dividing your polygon into regions using shapes such as rectangles, hexagons, and triangles' [p.268]. Tessellation techniques have gained substantial momentum in Geographic Information Systems to 'represent information about a land's surface within a computer system rather than on the original paper maps' [Gold, 2016, p. 9].

The map below displays Bayou Texar, a hydrologic feature located in east Pensacola, Florida. A local high school's science department has placed four sampling stations throughout the bayou, charged with taking water samples that measure nitrogen and phosphorous levels, tide levels, and amounts of rain at each station's respective location. Since it is impossible to take water samples at every geographic point within the bayou, tessellation is a technique that can be used as a precursor to interpolation or creating a 'continuous surface from sampled point values' [ESRI, 2025].

Tessellation divides the area into discreet units that can be used in various calculations, such as nearest neighbor [Thiessen polygons], to determine estimated values for each unit of the tessellated grid. This process provides an approximated value for every area of the feature class, as opposed to confining the collected data to the sites of the sampling stations. Tessellation can also provide other insight to any areal unit within a GIS, such as systemizing optimal locations for future sampling stations or also creating a spatial "index" to create a frame of reference.  The number of use-cases for tessellation is unquantifiable, but those mentioned in this discussion are among the most common for this function.

Sources:

ESRI. [2025]. An Overview of the Interpolation Toolset. Environmental Science Research Institute. <LINK>https://pro.arcgis.com/en/pro-app/latest/tool-reference/spatial-analyst/an-overview-of-the-interpolation-tools.htm

Gold, C. [2016]. Tessellations in GIS: Part I—putting it all together. Geo-spatial Information Science, 19[1], 9-25.

Obe, R., & Hsu, L. [2021]. PostGIS in Action. Simon and Schuster.