One-Hundred and Five-Hundred Year Floodzones for Unincorporated Areas in Illinois

Metadata:

• Identification_Information
• Data_Quality_Information
• Spatial_Data_Organization_Information
• Spatial_Reference_Information
• Entity_and_Attribute_Information
• Distribution_Information
• Metadata_Reference_Information
• Lineage

Identification_Information:

Citation:

Citation_Information:

Originator: Illinois State Water Survey

Publication_Date: 1996

Title:

One-Hundred and Five-Hundred Year Floodzones for Unincorporated Areas in Illinois

Edition: 20060817

Geospatial_Data_Presentation_Form: vector digital data

Series_Information:

Series_Name: ISGS GIS Database

Issue_Identification: GISDB_HYDRO.IL_Flood_Zones_1986_Py

Description:

Abstract:

Flood zone maps for Illinois are currently being re-mapped. Please refer to the ISWS/FEMA Map Modernization Program at <http://www.illinoisfloodmaps.org/>.

This feature class was quickly assembled from old Arc/Info coverages to produce a general graphic image and has not been reviewed or quality-controlled in any way and is not supported.

This is a statewide polygon feature class of 100 year and 500 year flood zones as of 1986 for the unincorporated areas of Illinois as indicated on Federal Emergency Management Agency (FEMA) National Flood Insurance Program (FIRM) maps and Flood Hazard Boundary maps.

The statewide data layer was created by appending data from 102 county-wide Arc/Info coverages originally released on Illinois DNR GIS data CDs dated 1996.

The data were digitized from paper maps. RMS values were not more than twenty feet in the original digitizing process. Mapscale: 1:6000 to 1:24,000.

Purpose:

These data are appropriate for use in local and regional thematic analysis. The data are not appropriate as a geodetic, legal or engineering base. The data set was not and is not intended as a substitute for surveyed locations, such as can be determined by a registered Public Land Surveyor. Although useful in a GIS as a reference base layer for maps, the data set has no legal basis in the definition of boundaries, property lines, or flood zones.

Supplemental_Information:

This statewide edition of the data is designated 20060817. The previous edition, stored as county-by-county coverages on the ISGS GIS system, was designated edition 1.0.

Time_Period_of_Content:

Time_Period_Information:

Single_Date/Time:

Calendar_Date: 1986

Currentness_Reference: As indicated on FEMA and FIRM maps

Status:

Progress: Complete

Maintenance_and_Update_Frequency: None planned

Spatial_Domain:

Bounding_Coordinates:

West_Bounding_Coordinate: -91.513518

East_Bounding_Coordinate: -87.495214

North_Bounding_Coordinate: 42.508002

South_Bounding_Coordinate: 36.987594

Keywords:

Theme:

Theme_Keyword_Thesaurus: none

Theme_Keyword: floodzones

Theme_Keyword: floodplain

Place:

Place_Keyword_Thesaurus: none

Place_Keyword: Illinois

Access_Constraints: none

Use_Constraints:

Reproduction or redistribution of copyrighted digital data sets or products derived therefrom outside of licensee's organization or entity is expressly forbidden. The only exception is redistribution to consultants working for the licensee, and then only for purposes, related to work for the licensee. Such consultants may not further reproduce or redistribute these data sets. None of these data shall be electronically duplicated on magnetic or optical media for use by others, in whole or in part, without permission of DNR.

Any hardcopies utilizing DNR data sets shall clearly indicate their source. If the licensee has modified the data in any way they are obligated to describe the types of modifications they have performed on the hardcopy map. Licensee specifically agrees not to misrepresent DNR data sets, nor to imply that changes they made were approved by DNR.

These data are not to be used for commercial profit.

Point_of_Contact:

Contact_Information:

Contact_Organization_Primary:

Contact_Instructions: Please refer to the distribution information.

Data_Set_Credit: GIS Processing: ISWS and ISGS staff

Native_Data_Set_Environment: ArcSDE 8.2 on Oracle 9i

Data_Quality_Information:

Attribute_Accuracy:

Attribute_Accuracy_Report: No report.

Logical_Consistency_Report: No report.

Completeness_Report:

Data are not included for incorporated areas of the state. Data for other areas may also be absent. There has been no quality-control or error checking performed on these data subsequent to compiling the county-by-county coverages into a statewide feature class.

Positional_Accuracy:

Horizontal_Positional_Accuracy:

Horizontal_Positional_Accuracy_Report: No report.

Lineage:

Process_Step:

Process_Description:

The 100 year and 500 year floodzones for the unincorporated areas as indicated on the Federal Emergency Management Agency (FEMA) National Flood Insurance Program (FIRM) maps and Flood Hazard Boundary maps were digitized from paper maps. When digitizing, all RMS values were not more than twenty feet.

Process_Date: Unknown

Process_Step:

Process_Description:

The 102 county-by-county coverages were compiled into a single statewide coverage. The coverage data were in the customary ISGS Lambert Conformal Conic projection. For the 98 county coverages with identical PAT items and definitions, this was accomplished with the Arc Workstation command APPEND, as follows:

APPEND FLOODZONES POLY <list of 98 coverages> END

The coverage was then cleaned, dissolved, and converted to a shapefile:

CLEAN FLOODZONES FLOODZONES2 0.002 0.002 POLY DISSOLVE FLOODZONES2 FLOODZONES3 COLOR POLY (the item COLOR contained the floodzone designations) ARCSHAPE FLOODZONES2 POLY floodzones.shp

The shapefile was imported into a personal geodatabase as a standalone feature class. The polygon data for the remaining four counties (Clark, Franklin, Kankakee, and Lawrence, which had irregular PAT items and definitions) were imported into the feature class using the Load function of ArcCatalog.

The data were then reprojected to lon/lat NAD83 using the Project function of ArcToolbox:

Executing (Project_1): Project C:\floodzones.mdb\floodzone_py C:\floodzones.mdb\floodzone_py_Project GEOGCS['GCS_North_American_1983',DATUM['D_North_American_1983',SPHEROID['GRS_1980',6378137.0,298.257222101]],PRIMEM['Greenwich',0.0],UNIT['Degree',0.0174532925199433]] NAD_1927_To_NAD_1983_NADCON Start Time: Thu Aug 17 09:48:45 2006 Executed (Project_1) successfully. End Time: Thu Aug 17 10:11:07 2006 (Elapsed Time: 22 minutes 22 seconds)

The values in field FLOODZONE were changed. Originally, a value of 72 indicated 100-year flood zone and a value of 70 indicated 500-year flood zone. These were changed to 100 and 500 respectively.

Process_Date: 20060816

Spatial_Data_Organization_Information:

Direct_Spatial_Reference_Method: Vector

Point_and_Vector_Object_Information:

SDTS_Terms_Description:

SDTS_Point_and_Vector_Object_Type: G-polygon

Point_and_Vector_Object_Count: 8438

Spatial_Reference_Information:

Horizontal_Coordinate_System_Definition:

Geodetic_Model:

Horizontal_Datum_Name: North American Datum of 1983

Ellipsoid_Name: Geodetic Reference System 80

Semi-major_Axis: 6378137.000000

Denominator_of_Flattening_Ratio: 298.257222

Geographic:

Geographic_Coordinate_Units: Decimal degrees

Latitude_Resolution: 0.000001

Longitude_Resolution: 0.000001

Vertical_Coordinate_System_Definition:

Altitude_System_Definition:

Entity_and_Attribute_Information:

Overview_Description:

Entity_and_Attribute_Detail_Citation: none

Detailed_Description:

Attribute:

Attribute_Label: SHAPE

Attribute_Definition: Feature geometry.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain: Coordinates defining the features.

Attribute:

Attribute_Label: floodzone

Attribute_Domain_Values:

Enumerated_Domain:

Enumerated_Domain_Value: 0

Enumerated_Domain_Value_Definition: not a flood zone

Enumerated_Domain:

Enumerated_Domain_Value: 100

Enumerated_Domain_Value_Definition: 100-year flood zone

Enumerated_Domain:

Enumerated_Domain_Value: 500

Enumerated_Domain_Value_Definition: 500-year flood zone

Attribute_Definition: Designation of flood zone type

Attribute_Definition_Source: Metadata of source coverages

Attribute:

Attribute_Label: FLOODZONE

Attribute:

Attribute_Label: FID

Attribute_Definition: Internal feature number.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain:

Sequential unique whole numbers that are automatically generated.

Detailed_Description:

Entity_Type:

Entity_Type_Label: IL_Flood_Zones_1986_Py

Attribute:

Attribute_Label: Shape

Attribute_Definition: Feature geometry.

Attribute_Definition_Source: ESRI

Attribute_Domain_Values:

Unrepresentable_Domain: Coordinates defining the features.

Distribution_Information:

Distributor:

Contact_Information:

Contact_Organization_Primary:

Contact_Organization: Illinois State Geological Survey

Contact_Address:

Address_Type: mailing and physical address

Address: 615 East Peabody Drive

City: Champaign

State_or_Province: Illinois

Postal_Code: 61820

Country: USA

Contact_Voice_Telephone: 217-333-4747

Contact_TDD/TTY_Telephone: 217-785-0211

Contact_Electronic_Mail_Address: isgs@isgs.uiuc.edu

Hours_of_Service: 8:00 a.m. - 4:30 p.m., Monday - Friday, U.S. Central Time

Distribution_Liability:

The Illinois Department of Natural Resources (DNR) provides these geographic data "as is." DNR makes no guarantee or warranty concerning the accuracy of information contained in the geographic data. DNR further makes no warranties, either expressed or implied as to any other matter whatsoever, including, without limitation, the condition of the product, or its fitness for any particular purpose. The burden for determining fitness for use lies entirely with the user. Although these data have been processed successfully on computers of DNR, no warranty, expressed or implied, is made by DNR regarding the use of these data on any other system, nor does the fact of distribution constitute or imply any such warranty.

In no event shall the DNR have any liability whatsoever for payment of any consequential, incidental, indirect, special, or tort damages of any kind, including, but not limited to, any loss of profits arising out of use of or reliance on the geographic data or arising out of the delivery, installation, operation, or support by DNR.

Technical_Prerequisites:

The data are intended for use with GIS software. The ISGS uses ESRI ArcGIS software, however, the ESRI shapefile format can be imported into many different GIS software packages. It is expected that customers who order this data have the technical expertise to use GIS software. The ISGS does not provide software support of any kind.

Metadata_Reference_Information:

Metadata_Date: 20060817

Metadata_Contact:

Contact_Information:

Contact_Instructions: Please refer to the distribution information.

Metadata_Standard_Name:

FGDC Content Standards for Digital Geospatial Metadata

Metadata_Standard_Version: FGDC-STD-001-1998

Metadata_Access_Constraints: None.

Metadata_Use_Constraints: None.

Metadata_Time_Convention: local time

Metadata_Extensions:

Online_Linkage: <http://www.esri.com/metadata/esriprof80.html>

Profile_Name: ESRI Metadata Profile

Lineage:

Illinois Natural Resources Geospatial Data Clearinghouse