HAMILTON COUNTY GEODETIC CONTROL Indiana GIS Conference February 19-20, 2008 H C

INTRODUCTIONS H C

Darren Wilson, GISP - GIS Specialist with the Surveyor’s - GIS Specialist with the Surveyor’s Office since 1999 Office since 1999 Val Swift, GISP - GIS Administrator with the Surveyor’s - GIS Administrator with the Surveyor’s Office since 1993 Office since 1993 H C

Kenton C. Ward, CFM - Hamilton County Surveyor since - Hamilton County Surveyor since Joseph Mullins, LS - Survey Manager with Surveyor’s - Survey Manager with Surveyor’s Office since September 2007 Office since September 2007 H C

Gary Ward - Section Corner Technician since - Section Corner Technician since November 2006 November 2006 Steve Fesmire - Survey Technician since January - Survey Technician since January H C

H C

A system of horizontal and/or vertical control stations that have been established and adjusted by geodetic methods and in which the shape and size of the earth (geoid) have been considered in position computations. A network of carefully measured points that can be used as a reference for other surveys or to establish or measure accuracy in map making. A network of points spread across the landscape where sturdy monuments have been placed in the ground, along with a high-accuracy positional value for each point. By referencing field survey measurements to such a network, the resulting survey data can be more accurately gathered. H C DEFINITION(S) Geodetic Control

SECTION CORNER PERPETUATION SECTION CORNER PERPETUATION H C - The Land Ordinance of 1785 created the Rectangular Public Land Survey System (PLSS) - Section-Township-Range System - Restoration/maintenance of section corners became the responsibility of the local or county surveyor - Today Administration of Section Corners are governed by Indiana Code

SECTION CORNER PERPETUATION SECTION CORNER PERPETUATION H C - Hamilton County has a total of approximately 7,225 “corners” - ie section corners, ¼ corners, 1/16 corners, center of sections - The Surveyor’s Office maintains approximately 1,700 section corners

H C 16 Survey Townships 9 Full Townships 7 Partial Townships T17N – R3E T17N – R4E T17N – R5E T17N – R6E T18N – R3E T18N – R4E T18N – R5E T18N – R6E T19N – R3E T19N – R4E T19N – R5E T19N – R6E T20N – R3E T20N – R4E T20N – R5E T20N – R6E

H C Surveyor’s Documents for Download Page OR age.asp?id=3121 Department Directory – Surveyor’s Office Page

H C PRE-2007

H C Linked using bookmarks Numbered using an alph-numeric grid system

H C MISSING STATE PLANE COORDINATE INFORMATION

H C NO GIS LAYER ONLY SCANNED PDF’s

H C SUMMER 2007

- GPS Base Station came online in Located on top of the Govt & Jud Ctr, downtown Noblesville - Part of the Midwest RTK VRS Network H C SUMMER 2007 cont.

- “Permanent” Part-time Section Corner Technician hired - Gary Ward working 30 hrs/wk - Revised the index sheet for the Section Corner Records - Created new Corner Record Sheet - Established new standards for field work - Created new Geodetic Control GIS Layer H C SUMMER 2007 cont.

H C THE RESULT?

H C NEW CORNER RECORD INDEX FOR ALL TWP PDF’s Corner Record Sheet linked to triangle on index CLEANER LOOK

H C IMPROVED MAP STATE PLANE COORDINATES HISTORICAL DOCUMENTATION COMMON CORNER INFORMATION IF APPLICABLE NEW CORNER RECORD SHEET

H C NEW PRE-CON CORNER RECORD SHEET MONUMENT NOT TIED DOWN STATE PLANE COORDINATES HISTORICAL DOCUMENTATION

H C NEW GIS LAYER CREATED WITH ArcGIS Currently 364 Points Finished Points - 37 Pre-Con Points

H C ATTRIBUTES

H C “X & Y” ATTRIBUTES - Points created in the.shp file by using the SKETCH TOOL and the “Absolute X,Y” Command 1. SKETCH TOOL 2. RIGHT-CLICK AND SELECT “ABSOLUTE X,Y” OR F6 - X and Y Points are then manually typed into the attributes table

H C “ PRE-CON ” ATTRIBUTE - Using a simple identifier, in this case a “Y”, allows you to differentiate between different types of points RED TRIANGLE FOR FINISHED PTS BLUE TRIANGLE- WAITING ON MONUMENTATION FROM THE STATE YELLOW TRIANGLE FOR PRE-CON PTS COUNTS FOR QC

H C “TIE SHEETS” ATTRIBUTE - Simple path set up as a hyperlink in the attribute table - Two types of hyperlinks: Field-based and Dynamic - Field-based is set up in the attribute table while dynamic allows you to specify a hyperlink directly to the feature in your map - We’ve chosen to utilize the Field-Based hyperlink

H C “TIE SHEETS” ATTRIBUTE - Field Calculator is used to fill in this field of the attribute table

H C “TIE SHEETS” ATTRIBUTE - The PDF resides on Hamilton County’s own web server - Anyone who downloads this GIS layer from the county’s website will have access to the Corner Record Sheet as long as they have internet access and Adobe Acrobat

H C “IDname” ATTRIBUTE IN02_T18NR05E01_08 - This attribute was created so we could participate in the Web Based - Tie Card Project Three County Tie Card Layers are complete and in maintenance: NEWTON CO. BARTHOLOMEW CO. JENNINGS CO. For more information go to:

H C “IDname” ATTRIBUTE - The committee members for the Tie Card Project developed a file naming convention that can be used statewide IN02_T18NR05E01_08 - Instead of changing our section corner numbering system we added a field in the attribute table STATE NAME AND PRIME MERIDIAN IN02 TOWNSHIP NUMBER AND DIRECTION T18N RANGE NUMBER AND DIRECTION R05E GRID NUMBER 08 SECTION NUMBER 01

H C “IDname” ATTRIBUTE - Cor_Num = Hamilton County’s Corner numbering system is based on Marion County’s system

H C “IDname” ATTRIBUTE - We must convert the Cor_Num attribute ( ) to the IDname attribute (IN02_T18NR05E01_08) GRID NUMBERINGHAMILTON COUNTY CORNER NUMBERING SYSTEM

H C “TIE SHEETS” ATTRIBUTE - Use Field Calculator to create IDname attribute - Expression: "IN02_T" + mid([Cor_Num],1,2) + "NR" + mid([Cor_Num],3,2) + "E" + mid([Cor_Num],5,2) + "_" + mid([Cor_Num],7,2) - The only thing left out is the conversion of the Position Number to the Grid Number - Right now that is manually entered

H C BENEFITS - Geodetic control networks support surveying, engineering, and GIS applications throughout Hamilton County - The devlopment of a modern digital control network is a form of basic infrastructure (much like roads or utilities) needed to support current and future needs - Creates a common, consistent, and accurate surveyed reference system - Provides surveyors, engineers, etc. with a referenced coordinate system for new projects

H C BENEFITS - With an improved, digital geodetic control network, relationships to other GIS layers can be shown with more confidence and reliability - Finally, accurate information is the key to making informed decisions. With an updated, digital geodetic control network forming the basis of survey and GIS data, the quality of all analysis and decision making has the chance to improve

H C SO WHAT’S LEFT TO DO?

H C - Update the remaining 1,336 section corner records and include them in the GIS layer - Have Corner Record Sheets created in a CAD or GIS software - Download points directly from data collectors into ArcGIS - Include some IF/THEN statements into the expression for the IDname attribute so the Position Numbers won’t have to be manually converted to the Grid Numbers for the Tie Card Project - Include our data on the Indiana GIS Atlas for the Web Based- Tie Card Project IN THE FUTURE…

H C - Once all 1,700 Section Corner Records are updated and in the GIS layer, replace the Township PDF Section Corner records with an Online GIS layer in the Hamilton County Online Maproom IN THE FUTURE…

H C QUESTIONS CONTACT INFORMATION Hamilton County Surveyor’s Office online at via at by phone at