Maps

I have used ArcMap, ArcGIS Pro, ArcGIS Online, QGIS, MapBox, Fusion, LAStools, and other programs to model, manage, and annotate spatial data in an academic and professional context. See below for examples of my work.


Assessing Sea Level Rise Impacts on California Sea Mussel Populations

This project was an analysis of how the distribution of sea mussels (Mytilus sp.) in rocky intertidal zones along the California coast might shift with projected sea level rise, using Natural Bridges State Beach as a study site.

Natural Bridges SLR 0

The sea mussel, genus Mytilus, is a bivalve mollusk found throughout the west coast of North America. Mussel beds are dominant in the middle intertidal zone, providing habitat and shelter for various invertebrates and algae. They are also a food source for larger animals like starfish, crabs, and sea otters. Their stable populations and relative immobility, combined with their importance in the ecosystem, makes them well-suited as an indicator species for how sea level rise might impact other species.

We used ArcGIS Pro to create a random forest model combining NOAA sea level rise data, USGS bathymetry data, and historical site-based mussel counts from the Monterey Bay National Marine Sanctuary’s LiMPETS program. The result of our analysis was three raster surfaces representing the predicted zonation of sea mussels at Natural Bridges State Beach with zero feet, three feet, and ten feet of sea level rise. Essentially, each pixel of each raster has an estimated value for mussel count based on the combined predictive value of the four input variables. This method allowed us to extrapolate observational data from a single transect across a much larger section of coastline.

Predicted mussel bed zonation at zero, three, and ten feet of sea level rise.

Of the input variables, elevation was the strongest predictor of mussel location, followed by distance to bluff. The model explained 80% of the variation in our results, though we expect that we could make our model even more accurate by adding more variables.

Overall, our results suggest that the range of potential mussel habitat may actually expand with sea level rise. We hypothesize that this could be a result of increased inundation over rocky intertidal areas lowering the risk of desiccation for mussels that would currently be susceptible to dangerous levels of sun exposure. Sea level rise could expand mussel beds’ upper range upshore toward the bluffs into upper tidal areas where they currently cannot survive.

Geoprocessing steps depicted in ArcGIS Model Builder

LiMPETS vertical transect data exists for 27 species at 27 sites up and down the California coast. Thus, our methods could be used to model the impacts of sea level rise on the zonation of mussels and other species elsewhere. As a next step, we recommended reproducing this analysis for other species that interact with mussels in the rocky intertidal zone in order to create a whole-ecosystem analysis in the context of sea level rise. We hope this preliminary research can provide a foundation for further study.

See our ArcGIS Online story map at this link.


Tubbs Fire Forest Characterization Study

I used Fusion and ArcMap to model aerial lidar data in order to characterize the canopy height and vegetation density of a forested area near the origin of the devastating 2017 Tubbs Fire.

TubbsPerimeterThese forest metrics can be used to better understand the landscape-level factors that contributed to the rapid spread of the blaze, including the role of ecological succession, the presence of sudden oak death, the regional topography, and the character of the forest mosaics at the urban-wildland interface.

Lidar data acquired in 2013 by the National Center for Airborne Laser Mapping (NCALM): https://doi.org/10.5069/G9BG2KW9

TubbsCHM
Canopy height reflects the mosaic of mixed hardwood-conifer forest, open chaparral, and developed property.
TubbsVegDensity
The study area was dominated by vegetation in the 20-40% density range interspersed with stands of denser foliage as well as clearings indicating development and open chaparral. CA-128, which roughly bisects the landscape, is clearly visible here.

TubbsCanopyCover

Methodology: I used Fusion and a command-line interface to convert the LAS point cloud into a digital elevation model (DEM), a digital surface model (DSM), a canopy surface model (CSM), and then a canopy height model (CHM). I used the CHM and the DSM to create a canopy cover model and a vegetation density model. Then, I converted the CHM, canopy cover, and vegetation density models into ASCII files and used the ASCII to Raster tool to render them in ArcMap. Finally, I used ArcMap to create classified maps representing CHM, canopy cover, and vegetation density.

Results: The study area, which previously burned in the 1960s and the 1980s, is characterized by three dominant land cover types: mixed hardwood-conifer forest, open chaparral, and developed property (vineyards, roads, and other infrastructure). The models indicate that in 2013, four years prior to the Tubbs Fire, the landscape was dominated by vegetation in the 20-40% density range, and the tallest trees were nearly 150 ft. Vegetation density did not necessarily correlate to canopy height in areas with returns above 25 ft, although the CHM and the density model do both reflect the landscape mosaic of forest, chaparral, and vineyard. The consistent distribution of young tree stands and medium-density canopy vegetation throughout the study area provides clues about how the Tubbs Fire invaded this plot from the east and quickly spread south toward Santa Rosa.


Wetland Habitat Suitability and Invasive Species Management Priorities in the Rodeo Lagoon Watershed, Marin County, CA

For this project, I conducted a habitat suitability study for wetland-adapted plants, then ran a density analysis on iNaturalist observations from the years 2009-2019 in order to illuminate areas of competition between native and non-native species within the Rodeo Lagoon Watershed in the Marin Headlands portion of the GGNRA.

RodeoConflictMapTommy
Fuzzy overlay raster created by combining kernel density layers for native and invasive wetland species. Dark red areas indicate a high concentration of both categories.

Mount Sutro Habitat Restoration Map

I created a public web map of active habitat restoration sites and native understory plant species within the Mt. Sutro Open Space Reserve. The purpose of this project is to provide public accountability and to spread awareness about efforts to enhance biodiversity in the open space. Users can query map points for habitat characteristics, including lists of which species have been planted at each site.

Click here to open the web app.

Screen Shot 2019-02-21 at 5.46.16 PM


IRWM Prop 1 Projects Map – San Francisco Bay Area

IRWM Prop 1 Project Map

I created this map to support the Integrated Regional Water Management (IRWM) Implementation Grant Program while serving as an intern at the San Francisco Estuary Partnership. This is an example of my ability to turn around a simple but comprehensive map product on short notice.