Slope Gradient
This feature class has been derived from a 1-meter gridded topographic-bathymetric terrain model that was resampled from the MarinMap "tbsm45cm_201008" surface.Resampling was performed using ERDAS Imagine. The surface gradient, expressed as percentage slope, was calculated using ESRI ArcGIS Spatial Analyst functions.ESRI Spatial Analyst Surface functions were used to define contour line features at 15-percent, 26-percent, and 36-percent over the seamless 1-meter countywide slope grid.Considerable effort was expended to build these contours into polygon areas that identify the four slope classes that are discriminated by those three contours.The complexity and the extreme variation in length of the contours made it necessary to dice the segments with a 200-meter grid to shorten the boundaries around the resulting polygons.Once a clean polygon build was successful countywide, centroid points were generated for each polygon and used to interpolate the percent slope grid under each point.These points were then reclassified into the CDA-defined categories, and a coded-value domain was defined for the classification as follows:0 - slope less than 15 percent1 - slope from 15--25 percent2 - slope from 26--35 percent3 - slope 36 percent and greaterThe label points with coded-value attributes were used with the clean bounding lines to generate the final set of countywide slope contours.The development work was performed in US National Grid (WGS 1984 UTM zone 10 north meters) and exported to an ESRI Feature Dataset to project this version to MarinMap customary system (NAD 1983 HARN California Coordinates zone 3 US Survey feet)
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[{'name': 'OBJECTID', 'type': 'esriFieldTypeOID', 'alias': 'OBJECTID', 'domain': None}, {'name': 'CDA_SlopeClass', 'type': 'esriFieldTypeSmallInteger', 'alias': 'CDA_slope_class', 'domain': {'type': 'codedValue', 'name': 'WS1_CDA_slope_range', 'description': 'Land slope regulatory ranges', 'codedValues': [{'name': 'slope less than 15 percent', 'code': 0}, {'name': 'slope from 15-25 percent', 'code': 1}, {'name': 'slope from 26-35 percent', 'code': 2}, {'name': 'slope 36 percent and greater', 'code': 3}], 'mergePolicy': 'esriMPTDefaultValue', 'splitPolicy': 'esriSPTDefaultValue'}}, {'name': 'SHAPE', 'type': 'esriFieldTypeGeometry', 'alias': 'SHAPE', 'domain': None}, {'name': 'SHAPE.STArea()', 'type': 'esriFieldTypeDouble', 'alias': 'SHAPE.STArea()', 'domain': None}, {'name': 'SHAPE.STLength()', 'type': 'esriFieldTypeDouble', 'alias': 'SHAPE.STLength()', 'domain': None}]
[{'name': 'R32_pk', 'fields': 'OBJECTID', 'isAscending': True, 'isUnique': True, 'description': ''}, {'name': 'S27_idx', 'fields': 'SHAPE', 'isAscending': True, 'isUnique': True, 'description': ''}]
[]
{'renderer': {'type': 'uniqueValue', 'field1': 'CDA_SlopeClass', 'field2': None, 'field3': None, 'defaultSymbol': None, 'defaultLabel': None, 'uniqueValueInfos': [{'symbol': {'type': 'esriSFS', 'style': 'esriSFSSolid', 'color': [52, 52, 52, 191], 'outline': {'type': 'esriSLS', 'style': 'esriSLSNull', 'color': [0, 0, 0, 0], 'width': 0}}, 'value': '3', 'label': 'slope 36 percent and greater', 'description': ''}, {'symbol': {'type': 'esriSFS', 'style': 'esriSFSSolid', 'color': [104, 104, 104, 191], 'outline': {'type': 'esriSLS', 'style': 'esriSLSNull', 'color': [0, 0, 0, 0], 'width': 0}}, 'value': '2', 'label': 'slope from 26--35 percent', 'description': ''}, {'symbol': {'type': 'esriSFS', 'style': 'esriSFSSolid', 'color': [156, 156, 156, 191], 'outline': {'type': 'esriSLS', 'style': 'esriSLSNull', 'color': [0, 0, 0, 0], 'width': 0}}, 'value': '1', 'label': 'slope from 15--25 percent', 'description': ''}, {'symbol': {'type': 'esriSFS', 'style': 'esriSFSSolid', 'color': [0, 0, 0, 0], 'outline': {'type': 'esriSLS', 'style': 'esriSLSNull', 'color': [0, 0, 0, 0], 'width': 0}}, 'value': '0', 'label': 'slope less than 15 percent', 'description': ''}], 'fieldDelimiter': ','}, 'transparency': 0, 'labelingInfo': None}
nan
nan