GIS Products

Map "users" ultimately defined the products generated; however, the demand for and the sophistication of products evolved over time as users perceived the value and capability of the GIS output. Users included decision makers from all disciplines, fire fighters, public information officers, BAER team members, researchers from universities, and the general public.

Initially, the most critical information required from the GIS lab was the fire perimeter. Twice per day, a helicopter with a GPS unit on board flew the fire perimeter, and a map was promptly produced for the fire fighters (Figure 1). Another critical datalayer was the location and condition of structures destroyed by the fire. The California Department of Forestry, Marin County Fire and NPS personnel surveyed homes in the burn area with GPS units (Trimble Navigation, Lt. ProXL and Basic Plus) and collected data on the condition and location of structures. Within four days of the fire ignition, and while the fire was still burning, these data were converted to a GIS datalayer and overlayed with a county parcel map to identify the owners of the structures.

Data were also gathered using GPS on location of hand lines, bulldozer lines, roads, trails, fire suppression effects, noxious weeds, vegetation plots, photo points, and survey points. GIS was then used for mapping, measuring, and monitoring post-fire analysis of burn effects and rehabilitation prescriptions. Examples of preliminary products generated include generalized location and identification of high to moderate burn intensity zones, of fire suppression measures, of cultural resources in relation to bulldozer lines, and of threatened and endangered species in relation to fire suppression actions. As users perceived the ability of GIS to measure and calculate information, they requested reports on acreage’s, linear distances, etc.

The park had several existing datalayers including soils, DLGs, DEMs and a few U.S. Geological Survey orthophoto quads; however, crucial, missing datalayer was a digital vegetation map. A recent Landsat TM image was available but it was not ground truthed and could only be used for general reference. Instead, a vegetation map was created using the U.S. National Resource Conservation Services (NRCS) digital soils map and cross-walking this information with the associated vegetation types. This proved surprisingly useful for some of the analyses with some adjustment based on spot checking with aerial photos.

More precise and inclusive information was added to the existing GIS databases. Examples include measuring more precisely the areal extent and location of potential soil erosion sites; monitoring the spread of noxious weeds, the recovery of vegetation communities; and more accurately locating roads and trails (the USGS DLGs were inaccurate). These data were crucial in assessing fire effects and guiding rehabilitation and mitigation prescriptions.

To speed up production of maps and to assure conformity in style, specially tailored, pre-existing programs (AML’s) were brought in and new ones developed. At one point, a California Department of Fish and Game Heritage Program species list of concern was plotted from the State Lands Commission in Sacramento via the internet on a plotter at Point Reyes.