SURFICIAL GEOLOGY - FEATURES



Field

Description

Main ID Information

Metadata Updated 2007

Title

Blue Earth County Aggregate Evaluation - Features (lines)

Filename

Sgsymln3 (ArcView Shapefile)

Abstract

This dataset consists of information about the types of landforms and features that are represented by an line (arc). These landforms consist of crevasse fills, eskers, and moraine ridges.

Place Keywords

Blue Earth County, Minnesota

Theme Keywords

Landforms, Features

Time Period of Content

Summer 1998

Parent Theme

NA (SG99XPY3)

Spatial Extent of the Data

Blue Earth County, Minnesota

Contact Person

Aggregate Resources Mapping Program

Contact Person Organization/Division

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

Purpose

To display linear geologic landforms and features that were too small to be mapped as polygons.

Progress

Complete

Currentness Reference

1998-1999

Maintenance Frequency

Non planned

Access Constraints

NA

Use Constraints

NA

Associated Data Sets

Surficial Geology (sg99xpy3.shp and sg99xln3.shp)

Data Quality

 

Attribute Accuracy

These lines were digitized off 1:24,000 topographic maps.

Logical Consistency

NA

Completeness

The units were delineated by aerial photograph interpretation (1:40,000) and transferred onto 1:24,000 topographic maps.

Horizontal Positional Accuracy

1:50000

Vertical Positional Accuracy

NA

Lineage

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; Figure 2). 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 Blue Earth 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, deltas, kames, 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

Raster only

 

Cell Width

NA

Cell Height

NA

Spatial Data Organization

 

Geographic Reference for Tabular Data

The lines represent geologic landforms that are too small to be mapped as polygons.

Native Dataset Environment

ArcView 3.1 / ArcInfo7.2.1

Vendor Specific Object Type

NA

Tiling Scheme

NA

Spatial Object Type

Vector

Transfer Size

87.9 kb

Entities -- Attributes

 

Entity-Attribute Overview

The lines represent geologic landforms that are too small to be mapped as polygons.

Entity-Attribute Detailed Citation

See table below: 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), filename_ (unique id for line, assigned by software), filename_i or filename_id if filename is less than 8 characters (an id usually assigned during theme creation).





Table Name

Field Name

Begin Column

Definition

Valid Values

Descriptions

Sgsymln3.shp

Uniqln_id

 

Number,3,0

250

Crevasse Fill - distinct

 

 

 

 

251

Crevasse Fill - less distinct

 

 

 

 

255

Esker - well defined

 

 

 

 

260

Moraine - distinct

 

 

 

 

261

Moraine - less distinct

 

Sgeolntype

 

Text, 30

Crevasse Fill - distinct

Landform description - Crevasse Fill - distinct

 

 

 

 

Crevasse Fill - less distinct

Crevasse Fill - less distinct

 

 

 

 

Esker - well defined

Esker - well defined

 

 

 

 

Moraine - distinct

Moraine ridge - distinct

 

 

 

 

Moraine - less distinct

Moraine ridge - less distinct