The Accuracy of Raster Data Tree Height Study in Prince George, Virginia Aerial Images Inaccurate Raster Data Created Using the LAS Dataset to Raster Tool Max Tree Height : 96 Feet Max Tree Height : 209 Feet Max Tree Height : 112 Feet Accurate Raster Data Created Using the Minus Tool There are numerous types of Raster Data that can be used to conduct a tree height study in Prince George, Virginia. However, there are certain tools that can be utilized in order to achieve the most accurate information. Studying specific height differences in a raster comparison will give insight to which file displays the most accurate information and it will also display which file did not exclude the ground elevation, which would make the object appear either taller or shorter. In a tree height study, the maximum elevation and the ground elevation should be taken into account for the most precise data. Abstract: The raster file created using the Minus Tool shows the most accurate information for the study. The data was created using the following inputs: the Digital Surface Model and the Digital Elevation Model from each study area. When this was complete, the outcome of the Minus Tool displayed the difference between the highest and lowest elevation data. This is useful because it indicates where the specific point elevation, or tree height, starts and stops. The compared raster shows the elevation for the entire area, but not for the specific point elevation, or tree height. This data was created using the LAS Dataset to Raster Tool, setting the filter of the dataset to “All”. When completed, the outcome will show the raster image for the entire area. However, when the image is classified, the data present does not show the data for the specific tree heights. It displays the data as if the lowest elevation was applied to each tree height. Using this, if a tree happened to be placed on a hill, the tree would seem much higher than one planted on a lower elevation, even if that was not the case. Graphs were produced to show a comparison between the two files. The graph above shows all of the different outcomes. If the data is compared, elevation changes can be observed. PG North indicated that the elevation of that study area does not alter. The two different types of raster overlap almost perfectly, meaning that the difference in the highest and lowest elevation did not differ from the entire elevation of the area. PG Central and South both show that the two raster files obtain different values. These graphs all indicate that, when comparing two different raster files, it is best to find the one that indicates the difference in the highest and lowest elevation, rather than find the one that applies the entire raster file to the full study. Value and Count fields lower than 10 were disregarded. The PG North data did not indicate a large amount of trees. The image above shows that the area has a query, which would limit the amount of space available for tree growth. The PG Central data did not indicate a large amount of trees. The image above shows that the area is urban, or developed land. So, the developed objects do not leave room for tree growth. The PG South data did indicate a large amount of trees. The image above shows that the developed land stops, turning into a forested area. This halt in developed land allows a large space for tree growth. Conclusion: Max Tree Height : 99 Feet Max Tree Height : 134 Feet By Josie Coleman Colonial Heights High School Special thanks to the Federal Emergency Management Agency for the data utilized in this study.