AGGREGATE POTENTIAL – BOUNDARIES BETWEEN

AGGREGATE POTENTIAL MAPPING UNITS

DODGE COUNTY, MINNESOTA

 

Field

Description

Main ID Information

Metadata Updated 2007

Title

Dodge County Aggregate Evaluation – Boundaries between Aggregate Potential Mapping Units

Filename

Agg02ln3 (ArcView Shapefile)

Abstract

This dataset consists of information about the types of geologic contacts, or boundaries, between the mapping unit polygons of the aggregate potential layer.  The seven types of contacts or boundaries are county border, geologic contact – inferred, geologic contact – well defined, channel scarp – inferred, channel scarp – well defined, glacial margin – inferred, channel margin – well defined.

Place Keywords

Dodge County, Minnesota

Theme Keywords

Geological contacts, channel scarps, glacial margin

Time Period of Content

Fall 2001 and Spring 2002

Parent Theme

NA (Agp02py3)

Spatial Extent of the Data

Dodge County, Minnesota

Contact Person

Aggregate Resources Mapping Program

Contact Person Organization/Division

Department of Natural Resources, Division of Lands and Minerals

Contact Person Position

Geologist or GIS Specialist

Contact Address

500 Lafayette Road, Box 45

Contact City

St. Paul

Contact Zip Code

55155-4045

Contact Voice Phone

651-259-5959

Contact Fax Phone

651-296-5939

Additional ID Information

 

Originator

Department of Natural Resources, Division of Lands and Minerals, Mineral Potential Section

Purpose

To differentiate the types of geological contacts so that various line symbols (e.g., solid lines, hatched lines, or dashed lines) can be used to show the contacts between polygons on a map.

Progress

Complete

Currentness Reference

All data was gathered in summer and fall of 2001 and compiled in the fall of 2001 through the spring of 2002.

Maintenance Frequency

None planned

Access Constraints

NA

Use Constraints

NA

Associated Data Sets

County Aggregate Mapping Program datasets for Dodge County, including data on sand and gravel potential, crushed stone potential, field observations, rock piles, and test pit quality.

Data Quality

 

Attribute Accuracy

The lines delineating the sand and gravel resources and surficial geology were digitized on screen with DOQs (1:12000 USGS Digital Orthophotoquadrangles) and DRGs  (1:24000 USGS scanned topographic maps – digital raster graphics) as the backdrops.  The lines delineating the crushed stone resources were based on a model to define a depth to bedrock surface (see the “Lineage” section below for additional information).

Logical Consistency

Overshoots, undershoots, etc. were fixed by a variety of techniques, thus the lines have been checked and completed.

Completeness

The sand and gravel resource units were delineated by aerial photograph (at a scale of 1:40,000) interpretation and digitized onscreen,  using ARCVIEW with 1:12000 USGS DOQs and 1:24000 USGS DRGs as the spatially registered backdrops.

Horizontal Positional Accuracy

1:50000

Vertical Positional Accuracy

Not applicable

Lineage

For sand and gravel:

Color infrared and black-and-white aerial photographs were used to delineate geological landforms and aggregate resources.  Stereoscopic pairs of color infrared aerial photographs (NAPP, 9"x9" at 1:40,000 scale, April 1991 and 1992) were used along with reconnaissance-level, high-altitude, black-and-white photographs (1:80,000 scale).  Aerial photographs (DOQs) were also available digitally and used within ARCVIEW (1:12,000 scale).  Aerial photographic interpretation was completed with a glacial mapping technique known as the landsystems approach.  This technique relies on the principle that depositional glacial landforms are composed of a predictable range of sediments, some consisting of sorted sand and gravel and others consisting of silts, clays, or unsorted materials.   In addition to the landsystems approach, several other general characteristics helped determine the nature of the material, such as tonal contrasts, texture, context, shape, size, trend, association, and patterns.  These characteristics can help determine the properties of the surface material (e.g., certain vegetation grows on well drained soils such as sand and gravel, which on an aerial photograph has a distinctive texture, tone, pattern, etc.).

 

The landform recognition approach (part of the landsystems approach) was also used when interpreting the topography within Dodge County; glacial landforms have distinct and unique shapes and patterns that can be observed in their topographic expression.  Topographic maps (USGS 1:24,000), digital elevation models, and shaded relief maps were all used to help delineate these sand and gravel bearing features.  The topographic expression of a feature can also be observed by looking at the distribution of lakes and wetlands.  For example, a string of lakes and/or wetlands may be the signature of a glacial outwash channel or collapsed channel, which may host sand or gravel deposits.  Several aggregate bearing features were located using this technique (outwash channels, collapsed channels, glaciofluvial fans, eskers, and terraces).

Source Scale Denominator

1:50000

Spatial Reference

 

Horizontal Coordinate Scheme

UTM

Ellipsoid

GRS80

Horizontal Datum

NAD83

Horizontal Units

Meters

Distance Resolution

NA

Altitude Datum

NA

Altitude Units

NA

Depth Datum

NA

Depth Units

NA

UTM Zone Number

15 Extended

Raster only

 

Cell Width

NA

Cell Height

NA

Spatial Data Organization

 

Geographic Reference for Tabular Data

.

Native Dataset Environment

ArcView 3.1 / ArcInfo 8.0.2

Vendor Specific Object Type

NA

Tiling Scheme

NA

Spatial Object Type

Vector

Transfer Size

 

Entities -- Attributes

 

Entity-Attribute Overview

The lines delineate the polygon mapping units found in the aggregate potential layer.  Note:  some of these lines, specifically the channel scarps and glacial margin, are also found in the sgeoxln3 shapefile, to enable the user to portray these special features as a continuous line symbol.

Entity-Attribute Detailed Citation

 ArcView specific fields include shape (i.e., feature type - polyline), fnode_ (id of beginning node of line), tnode_ (id of ending node of line), lpoly_ (id of polygon to the left of the line - “0" if a line feature, not a line defining a polygon), rpoly_ (id of polygon to the right of the line - “0" if a line feature, not a line defining a polygon), length (length of the line segment), agp02ne3_ (unique id for line, assigned by Arc/INFO software), agp02ne3_i (an id usually assigned during theme creation).

The aggregate potential line attributes are described in the table below.

 

 

Table Name

Field Name

Begin Column

Definition

Valid Values

Descriptions

Agg02ln3.shp

Uniqln_id

 

Number,3,0

1

Dodge County Boundary

 

 

 

 

261

Geological contact - well defined

 

 

 

 

262

Geological contact – inferred

 

 

 

 

265

Channel Scarp - well defined

 

 

 

 

266

Channel Scarp – inferred

 

 

 

 

270

Glacial Margin – well defined

 

 

 

 

271

Glacial Margin - inferred

 

Agplntype

 

Text, 33

County Boundary

Descriptions of unique Identifiers

 

 

 

 

Geological Contact (Well Defined)

Geological contact - well defined

 

 

 

 

Geological Contact (Inferred)

Geological contact - inferred

 

 

 

 

Channel Scarp (Well Defined)

Channel Scarp - well defined

 

 

 

 

Channel Scarp (Inferred)

Channel Scarp - inferred

 

 

 

 

Glacial Margin (Well Defined)

Glacial Margin – well defined

 

 

 

 

Glacial Margin (Inferred)

Glacial Margin - inferred