Description: <DIV STYLE="text-align:Left;"><DIV><DIV><P STYLE="margin:0 0 14 0;"><SPAN>The Santa Clara County Impervious Surfaces map (v. 6/7/22) is a 5-class fine-scale polygon vector representation of all artificial impervious surfaces in Santa Clara County.There are 1,866,057 features in the dataset. Non-impervious areas are not mapped and are not covered by polygons. The impervious map represents the state of the landscape in summer, 2020. This data product was produced by the impervious mapping team at the University of Vermont Spatial Analysis Lab. Table 1 lists download locations for the dataset.</SPAN></P><OL STYLE="margin:0 0 0 0;padding:0 0 0 0;"><LI><P STYLE="margin:0 0 0 0;"><SPAN><SPAN>Santa Clara County impervious surfaces data product availability</SPAN></SPAN></P></LI></OL><TABLE><TBODY><TR><TD><P STYLE="text-align:Center;font-weight:bold;margin:0 0 0 0;"><SPAN><SPAN>Description</SPAN></SPAN></P></TD><TD><P STYLE="text-align:Center;font-weight:bold;margin:0 0 0 0;"><SPAN><SPAN>Link</SPAN></SPAN></P></TD></TR><TR><TD><P STYLE="margin:0 0 0 0;"><SPAN><SPAN>File GDB</SPAN></SPAN></P></TD><TD><P STYLE="margin:0 0 0 0;"><A href="https://vegmap.press/Santa Clara_impervious_fgdb" STYLE="text-decoration:underline;"><SPAN STYLE="text-decoration:underline;"><SPAN>https://vegmap.press/Santa Clara_impervious_fgdb</SPAN></SPAN></A></P></TD></TR><TR><TD><P STYLE="margin:0 0 0 0;"><SPAN><SPAN>ArcGIS Pro Layer Package</SPAN></SPAN></P></TD><TD><P STYLE="margin:0 0 0 0;"><A href="https://vegmap.press/Santa Clara_impervious_layer_package" STYLE="text-decoration:underline;"><SPAN STYLE="text-decoration:underline;"><SPAN>https://vegmap.press/Santa Clara_impervious_layer_package</SPAN></SPAN></A></P></TD></TR><TR><TD><P STYLE="margin:0 0 0 0;"><SPAN><SPAN>Vector Tile Layer</SPAN></SPAN></P></TD><TD><P STYLE="margin:0 0 0 0;"><A href="https://vegmap.press/Santa Clara_impervious_vector_tile_layer" STYLE="text-decoration:underline;"><SPAN STYLE="text-decoration:underline;"><SPAN>https://vegmap.press/Santa Clara_impervious_vector_tile_layer</SPAN></SPAN></A></P></TD></TR></TBODY></TABLE><P /><P STYLE="margin:0 0 14 0;"><SPAN STYLE="font-weight:bold;"><SPAN>Detailed Dataset Description</SPAN></SPAN><SPAN><SPAN>:</SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN /><SPAN /><SPAN /><SPAN><SPAN>The impervious map was created using “expert systems” rulesets developed in Trimble Ecognition. These rulesets combine automated image segmentation with-object based image classification techniques. In contrast with machine learning approaches, expert systems rulesets are developed heuristically based on the knowledge of experienced image analysts. Key data sets used in the expert systems rulesets for impervious mapping included: high resolution (6 inch or greater) 4-band orthophotography (2020), the lidar point cloud (2020), and lidar derived rasters such as the canopy height model. </SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN>After it was produced using Trimble Ecognition, the preliminary impervious map product was manually edited by a team of UVM’s photo interpreters. Manual editing corrected errors where the automated methods produced incorrect results. </SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN /></P><P STYLE="margin:0 0 14 0;"><SPAN>The impervious map has 5 classes, which are described below:</SPAN></P><UL><LI><P STYLE="font-weight:bold;"><SPAN><SPAN>Building </SPAN></SPAN><SPAN><SPAN>–</SPAN></SPAN><SPAN><SPAN> </SPAN></SPAN><SPAN><SPAN>Structures including homes, commercial buildings, outbuildings, and other human-made structures such as water tanks and silage silos. Structures fully occluded by vegetation will not be mapped.</SPAN></SPAN></P></LI><LI><P STYLE="font-weight:bold;"><SPAN><SPAN>Paved Road </SPAN></SPAN><SPAN><SPAN>–</SPAN></SPAN><SPAN><SPAN> </SPAN></SPAN><SPAN><SPAN>Roads that are paved and wide enough for a vehicle.</SPAN></SPAN></P></LI><LI><P><SPAN STYLE="font-weight:bold;"><SPAN>Dirt/Gravel Road </SPAN></SPAN><SPAN><SPAN>–</SPAN></SPAN><SPAN STYLE="font-weight:bold;"><SPAN> </SPAN></SPAN><SPAN><SPAN>Dirt or gravel roads wide enough for a vehicle. Non-ephemeral fire roads, ranch roads and long driveways. Polygons representing narrow unpaved (single track) trails are not included in this data product.</SPAN></SPAN></P></LI><LI><P><SPAN STYLE="font-weight:bold;"><SPAN>Other Dirt/Gravel Surface </SPAN></SPAN><SPAN><SPAN>– Dirt or gravel surfaces that are highly compacted and used by humans and equipment, such as parking lots, road pull-offs, some dirt or gravel paths, and highly compacted areas around commercial activities. This class DOES NOT include natural turf playing fields, very lightly used dirt roads, livestock areas, naturally occurring bare soil or rock, or bare areas around ponds.</SPAN></SPAN></P></LI><LI><P STYLE="font-weight:bold;"><SPAN><SPAN>Other Paved Surface </SPAN></SPAN><SPAN><SPAN>–</SPAN></SPAN><SPAN><SPAN> I</SPAN></SPAN><SPAN><SPAN>ncludes parking lots, sidewalks, paved walking paths, swimming pools, tennis courts. </SPAN></SPAN></P></LI></UL><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>Miscellaneous quality control and processing notes:</SPAN></SPAN></P><UL><LI><P><SPAN><SPAN>Zoom level used during manual quality control was no finer than 1 to 500.</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>Vector data was created with no overlapping polygons.</SPAN></SPAN></P></LI></UL><P STYLE="font-weight:bold;margin:0 0 14 0;"><SPAN><SPAN>Data Limitations:</SPAN></SPAN></P><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>This is not a planimetric data product and was created using semi-automated techniques. It provides a reasonable and useful depiction of impervious surfaces for planner and managers but does not have the accuracy or precision to support engineering. </SPAN></SPAN><SPAN><SPAN>Please note that this dataset does not contain information about ownership potential access restrictions. </SPAN></SPAN><SPAN><SPAN>Appropriate uses of the data product include: </SPAN></SPAN></P><UL><LI><P><SPAN><SPAN>As an input to storm water models</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>For planners to assess % imperviousness in a parcel/watershed</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>To help identify areas of human infrastructure for fuels and fire management</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>As an input to fuel models that are used in fire behavior and fire spread models</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>For cartography and mapping</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>Generally for use at scales 1:1,000 and smaller</SPAN></SPAN><SPAN /></P></LI></UL><P STYLE="margin:0 0 14 0;"><SPAN><SPAN>Inappropriate uses of this product include:</SPAN></SPAN></P><UL><LI><P><SPAN><SPAN>Measuring exact square footage of structures or impervious features for building projects</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>Using the impervious as geographically precise information in transportation and public works</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>Determining ownership or maintenance responsibility of a particular feature, such as a paved or dirt road</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>Identifying publicly accessible areas for recreation or other uses</SPAN></SPAN></P></LI><LI><P><SPAN><SPAN>Confirming the suitability of a surface for any use including driving, hiking, bicycling, etc.</SPAN></SPAN><SPAN /></P></LI></UL></DIV></DIV></DIV>
Service Item Id: 67eefd71f1e8412db2618acc306c881f
Copyright Text: San Mateo County Resource Conservation District, CALFIRE, Santa Clara Mountains Stewardship Network, Midpeninsula Regional Open Space District, County of Santa Clara, Tukman Geospatial LLC