# Presentation: 684096

## SDTS Case Studies

**USGS products**
**Vector with topology**
**DLG-3:  Digital Line Graph with full topology**
**DLG-F:  Digital Line Graph with Features**
**Raster**
**DEM:  Digital Elevation Model**
**DOQ:  Digital Orthophoto Quadrangle**

## Case Study: DLG-3

**Which Profile?   TVP**
**Use Master Data Dictionary ****(Annex A)**
**Attributes**
**table for each theme (hydrography, boundaries, etc.)**
**table for header metadata when no standard subfield**
**Auxiliary Information**
**definitions & dq statements**
**What is a transfer?**
**salable unit; multiple tiles and layers**

## DLG-3: Spatial Object Mapping

**    ****SDTS**
**Node, planar**
**Complete Chain**
**GT-Polygon**
**Area Point**
**Entity Point**
**Universe Polygon**
**2-D Manifold**

**   ****DLG-3**
**Node**
**Line**
**Area**
**Area Rep Point**
**Degen. Line**
**Outside Area**
**DLG**

***Use definitions to do the mapping***

## DLG-3 Attributes in SDTS

- In the DLG native file:
- Line 23 has attribute codes:170 0603, 173 0075, 170 0203, 171 0004, 170 0615

- In SDTS/TVP format:

- 1700203 in Data Dictionary with meaning “Class 1, divided, lanes separated”.

**Notes:**
The conversion of major/minor codes for this example is:

170 0603 = Operrational Status, value “U” = under construction
173 0075 = Route Number US 75
170 0203 = Entity Label value
171 0004 = Lanes, value 4
170 0615 = Route Type, value “Bypass”

The document describing all of the rules and conversions for each theme is available at the SDTS FTP site, under datasets/tvp/dlg3.

## Case Study: DLG-3

**Case Study: DLG-3**

**One dlg file + Data Users Guide becomes...**
- TR01AHDR.DDF   TR01AROD.DDF   TR01AHRR.DDF   TR01AHMT.DDF**   TR01CATD.DDF   TR01CATS.DDF   TR01DDSH.DDF   **_**TR01DQAA.DDF**_
_**TR01DQCG.DDF**_**   **_**TR01DQHL.DDF**_**   **_**TR01DQLC.DDF**_**   **_**TR01DQPA.DDF**_**   TR01IDEN.DDF   TR01IREF.DDF   ****TR01LE01.DDF   TR01LE02.DDF   TR01LE03.DDF   TR01NA01.DDF   TR01NA02.DDF   TR01NA03.DDF   TR01NE01.DDF   TR01NE02.DDF   TR01NE03.DDF   TR01NO01.DDF   TR01NO02.DDF   TR01NO03.DDF   TR01PC01.DDF   TR01PC02.DDF   TR01PC03.DDF****   TR01SPDM.DDF   TR01STAT.DDF **** ****PRNMXREF.DDF   README**
**One transfer is many files**
**Spatial data**** + **attributes** + metadata + **_**narrative data quality**_

## DLG-3 Identification Module

**SDTS Report**
**Input DDF file:  hy01iden.ddf**
**Field Subfield Format Length Data**
**----- -------- ------ ----- ----**
**0001                      6      1**
**IDEN  MODN     A          4 IDEN**
**IDEN  RCID     I          6      1**
**IDEN  STID     A         30 SPATIAL DATA TRANSFER STANDARD**
**IDEN  STVS     A         12 1994 JUNE 10**
**IDEN  DOCU     A         14 FIPS PUB 173-1**
**IDEN  PRID     A         31 SDTS TOPOLOGICAL VECTOR PROFILE**
**IDEN  PRVS     A         25 VERSION 1.0 JUNE 10, 1994**
**IDEN  PDOC     A         17 FIPS 173-1 PART 4**
**IDEN  TITL     A         37 WILMINGTON SOUTH, DE-NJ / HYDROGRAPHY**
**IDEN  DAST     A          5 DLG-3**
**IDEN  MPDT     A          4 1987**
**IDEN  DCDT     A          8 19951031**
**IDEN  SCAL     I          8    24000**
**IDEN  COMT     A        164 This transfer requires an external data dictionary...**
**CONF  FFYN     A          1 Y**
**CONF  VGYN     A          1 Y**
**CONF  GTYN     A          1 Y**
**CONF  RCYN     A          1 N**
**CONF  EXSP     I          1 1**
**CONF  FTLV     I          1 4**
**$$$$$ END OF FILE $$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$**

## DLG-3 Data Quality Statements

- Example of **Lineage** statement:
- This Digital Line Graph was digitized from a standard U.S. Geological Survey (USGS) quadrangle (name, date and scale of quadrangle indicated in SDTS Identification Module). The digital data were produced by either scanning or manually digitizing a stable-based copy of the graphic materials.  The scanning process captured the digital data at a scanning resolution of at least 0.001 inches;  the resulting raster data were vectorized and then attributed on an interactive editing station.  Manual digitizing used a digitizing table to capture the digital data at a resolution of at least 0.001 inches;  attribution was performed either as the data was digitized, or on an interactive edit station after the digitizing was completed.  (etc.)
- Example of **Logical Consistency **statement:
- Certain node/geometry and topology (GT)-polygon/chain relationships are collected or generated to satisfy topological requirements.  (The GT-polygon corresponds to the DLG area).  Some of these requirements include: chains must begin and end at nodes, chains must connect to each other at nodes, chains do not extend through nodes, left and right GT-polygons are defined for each chain element and are consistent throughout the transfer, and the chains representing the limits of the file (neatline) are free of gaps. (etc.)

## Case Study: DLG-F

**Digital Line Graph - Features**
**vector topology with features**
**Which Profile?   TVP ****(for now)**
**Feature is a SDTS Composite**
**carries all the feature attributes**
**feature composed of spatials or features**
**Composites used in DLG-F**
**to model any object that had attributes and participate in relationships**
***theme, surface, and feature***
**Feature Relationships as SDTS Attributes**

## Model Mapping Document

**Deliverable from Model Mapping Process**
**Purpose****: ****“****to describe how the DLG-F Model  maps into the SDTS****”**
**Uses**
**software requirements for encoding or decoding**
**case study for others**
**Organization of Document:**
**Part 1: Describes DLG-F Model**
**Part 2: DLG-F to SDTS Mapping**
**Part 3: Describes Transfers**

## DLG-F: SDTS Modules

**IDEN**

**CATD**

**STAT**

**CATS**

**IREF**

**XREF**

**SPDM**

**DQHL**

**DQPA**

**DQAA**

**DQCG**

**DQLC**

**COMP:surface**

**COMP:theme**

**COMP:feat(3)**

**ATSC: reln(7)**

**ATPR:**
**feature**
**(~113)**
**others(8)**

**DDSH**

**PNTS(3)**

**POLY**

**LINE**

## Case Study: DEM

**Digital Elevation Model**
**regular grid of elevation values**
**Which Profile?  Raster Profile**
**Spatial Object Mapping**
**grid cells contain elevation value**
**grid as single layer**
**Scan Order and Pattern**
**chose to reorder our native format to normalize the data order (was bottom left, south to north, west to east)**
**top left, west to east, north to south**
**fill to make non-ragged**

## DEM: SDTS Modules

**DDSH**

**RSDF**

**LDEF**

**CELL**

**IDEN**

**CATD**

**STAT**

**IREF**

**XREF**

**DQHL**

**DQPA**

**DQAA**

**DQLC**

**DQCG**

**DD/Schema**

**Raster Definition**

**Layer Definition**

**Cell Values**

**DDDF**

**DDOM**

**DD/Definition**

**DD/Domain**

## Case Study: DOQ

**Digital Orthophoto Quadrangle**
**rectified areal photography**
**Which Profile?  Raster Profile**
**Still in planning stages**
**No Mapping Doc available yet**
**Spatial Object Mapping**
**pixels; digital image**
**one layer of pixels**
**Compression**
**JPEG JFIF or BIIF adjunct file (?tbd)**

## Case Study: DOQ

**IDEN**

**CATD**

**STAT**

**IREF**

**XREF**

**DQHL**

**DQPA**

**DQAA**

**DQLC**

**DQCG**

**DDSH**

**RSDF**

**LDEF**

**CODING**

**JPEG or BIIF**
**(adjunct file)**

## Option: DOQ Chips

**Another scenario for the DOQ Product Mapping**
**Users selects a small area of a larger high resolution dataset**
**This chip is packaged as a transfer**
**Consider using GeoTIFF ****(?TBD)**