Addison's GIS Journey

Land Use Land Cover (LULC) and Ground Truthing were covered this week. LULC classification is used for urban planning, natural resource inventory, and others. There are multiple classification systems to identify features but the USGS Standard Land Use/Land Cover Classification System was used in this lab.  There are three types of ground truthing: calibration, accuracy assessment, and field spectra. In this lab accuracy assessment was used to verify that classification/interpretation was correct. This type of ground truthing is done soon after image acquisition. The map below shows an area of Pascagoula, Mississippi. The different colored and labeled polygons represent different features within the image based on the classification system used. The points represent the ground truthing accuracy assessment that was done using random sampling points; where the green represent points that were accurate and red represents points that were inaccurate.  

 This weeks lab was an introduction to Aerial photo basics and the methods and techniques used to visually interpret them.  Aerial photography provides a unique perspective that is used in multiple fields. Since aerial photographs are taken from an elevated position they can reveal features and patterns that we may not be able to see. Understanding the basic techniques and methods to interpret these images can provide valuable insight to the area.  The recognition elements focused on in this lab include: tone, texture, shape and size, shadows, pattern, and associating. The image below depicts areas of different tones and textures. The red outlined areas represent various tones: very dark, dark, medium, light, and very light. When examining the image for tone it is important to keep in mind the uniformity of the tone within the area. While the purple outlined areas represent various textures: very coarse, coarse, mottled, fine, and very fine. Withing the picture the very f...

This weeks lab focused on the effects of scale and resolution on the properties of spatial data, and the Modifiable Area Unit Problem (MAUP).  Vector data is highly dependent on scale, at larger scales(closer view) features are represented with more detail. While at smaller scales(zoomed out) the data will have less data which may require generalization when analyzing. Vector data should be adapted when using different scales to maintain interpretability. Resolution within raster data refers to the size of the grid cells/pixels used to make the dataset. High resolution raster will have smaller pixels, which creates better detail. Low resolution raster will have larger pixels, which may lead to generalizing the information within the raster. Choosing the best resolution is important since it can directly impact the type of analysis and its accuracy. Gerrymandering is the manipulation of the boundaries of an electoral constituency so as to favor one party or class. District lines are...