SURFICIAL
GEOLOGY – GLACIAL MARGIN AND SCARPS
DODGE COUNTY,
MINNESOTA
Field |
Description |
Main ID Information |
Metadata Updated 2007 |
Title |
Dodge County Aggregate
Evaluation – Glacial margin and
Scarps (lines) |
Filename |
Sgeoxln3 (ArcView
Shapefile) |
Abstract |
This dataset consists
of information about the types of landforms and features that are best
represented on a map by a line (or arc).
These landforms include channel scarps and glacial margins. |
Place Keywords |
Dodge County, Minnesota |
Theme Keywords |
Landforms, geologic
features |
Time Period of
Content |
Fall 2001 – Spring 2002 |
Parent Theme |
NA (Agg02py3) |
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 |
651-296-4807 |
Contact Fax Phone |
651-296-5939 |
Additional ID
Information |
|
Originator |
Department of Natural Resources,
Division of Lands and Minerals, Mineral Potential Section |
Purpose |
To represent small,
linear, surficial geologic landforms and features on a map as lines, because
they are too small to be represented by a polygon. |
Progress |
Complete |
Currentness
Reference |
All data was gathered
in the late 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. |
Data Quality |
|
Attribute Accuracy |
|
Logical Consistency |
|
Completeness |
The mapping units were
delineated by aerial photograph (at a scale of 1:40000) 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 |
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 at
1:12000) were also available digitally and used within ARCVIEW. 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 |
15E |
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 |
Point |
Tiling Scheme |
Dodge County |
Spatial Object Type |
Point |
Transfer Size |
10 kb |
Entities --
Attributes |
|
Entity-Attribute
Overview |
The lines represent
geologic landforms that are too small to be mapped as polygons. Note:
some of these lines are also found in the agg02ln3 shapefile, because they
form the boundary between two polygon mapping units. |
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 line segment), sgeoxln3_ (unique id for line, assigned by Arc/INFO software), sgeoxln3_i (an id usually assigned during theme creation). The
scarp line attributes are described in the table below. |
Table Name |
Field Name |
Begin Column |
Definition |
Valid Values |
Descriptions |
Sgeoxln3.shp |
Uniqln_id |
|
Number,3,0 |
265 |
Channel Scarp - well
defined |
|
|
|
|
266 |
Channel Scarp -
inferred |
|
|
|
|
270 |
Glacial margin – well
defined |
|
|
|
|
271 |
Glacial margin –
inferred |
|
Sgeolntype |
|
Text, 33 |
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 |