Lab 2 [GIS5027L]: Land Use / Land Cover Classification and Accuracy Assessment


This map demonstrates practice creating polygons representative of land use / land cover by examining the underlying features in the aerial photograph for details relevant to classify at Level II of the USGS Standard Land Use / Land Cover Classification System.

This lab further demonstrated ways to utilize Google maps as  part of ground truthing a random set of 30 points drawn throughout the image to measure overall accuracy (shown in the map above at 70%).

Comments

Post a Comment

Popular posts from this blog

Lab 1 [GIS5935]: Calculating Metrics for Spatial Data Quality

Image
  Precision provides an assessment of the consistency of a measurement method (Bolstad, 2016, p. 624), or how close the measured values are to each other. The most commonly used measurement of precision is the distance that includes 68% of the repeated observations. For this dataset, as noted in the map legend above, the 68% horizontal precision value is 4.5 m. This means that 68% of independent observations are within 4.5 m of the average location. Alternatively, accuracy provides an assessment of how close a value is to the true value (Bolstad, 2016, p. 624). In this lab, horizontal accuracy was estimated as the distance between the average location and a known reference point, and was determined to be approximately 3.25 m.  With horizontal accuracy estimated as 3.25 m and 68% horizontal precision estimated as 4.5 m, we note a significant difference of 1.25 m between these values. Using a 68% horizontal precision value estimate means there are still 32% of the observations t...
Read more

Lab 5 [GIS6105]: Tessellation

Image
  The final map I created in this lab includes some preliminary analysis of the differences in average dissolved oxygen levels as a side-by-side comparison for January 2014 versus February 2014. In this example I used graduated symbols colored red (dangerous level), yellow (warning level), and green (acceptable level). This provides visual cues on areas within Bayou Texar that may be at risk for water quality issues. A tessellated surface for this feature would be very useful to show the scope of the impact of the change in values from the northern to southern regions of this waterway. For example, for the results from January 2014, the tessellated cells colored near the northernmost site could provide guidance on how far in this area community groups could explore for potential contributing causes. Tessellated surfaces would also be beneficial for examining temperature-related data for this case study, as well as other environmental impact case studies where water temperature/qual...
Read more

Lab 5 [GIS5007]: Choropleth and Proportional Symbol Mapping

Image
This week's lab used both ArcGIS Pro and Adobe Illustrator to address a number of important considerations when designing maps, including the significance of using an appropriate projection (equal area) with choropleth map visualizations for population densities and factors to consider when selecting various classification schemes for data sets. For the data set above, the projection used is Europe Albers Equal Area Conic. This projection is particularly useful for choropleth mapping because it preserves area, which is critical when mapping densities. In this particular lab, we are mapping population density per unit area across European countries. Given this, it is critical to have a projection optimized at the continental scale so the unit area looks the same size across this region. To communicate the map theme, two different classification schemes are employed in this map, with classes selected to maximize overall contrast. This map uses the Quantile classification...
Read more