1 MANAGING COMMON OREGON MAP PROJECTIONS IN ARC MAP I. Common Map Projections Used in the State of Oregon The following text blocks provide a listing of the critical parameters for UTM Zone10 N, StatePlane North, and Oregon Custom Lambert. These will be the primary projections we will be using for work on Oregon GIS in our neighborhood. UTM Zone 10 N NAD1927 Units: meters False Easting: 500000 False Northing 0 Prime Meridian: Greenwich Transverse Mercator Central Meridian: -123 Central Parallel: 0 Scale Factor: 0.9996 Ellipsoid (spheroid): Clarke 1866 UTM Zone 11 N NAD1927 Units: meters False Easting: 500000 False Northing 0 Prime Meridian: Greenwich Transverse Mercator Central Meridian: -117 Central Parallel: 0 Scale Factor: 0.9996 Ellipsoid (spheroid): Clarke 1866 Oregon State Plane North - NAD 1983 – Feet International Units: feet False Easting: 2500000 False Northing 0 Prime Meridian: Greenwich Lambert Conformal Conic Central Meridian: -120.5 Central Parallel: 43.6666 Standard Parallel 1: 44.333333 Standard Parallel 2: 46 Ellipsoid (spheroid): GRS 1980 Oregon State Plane South - NAD 1983 – Feet International Units: feet False Easting: 1500000 False Northing 0 Prime Meridian: Greenwich Lambert Conformal Conic Central Meridian: -120.5 Central Parallel: 41.6666 Standard Parallel 1: 42.333333 Standard Parallel 2: 44 Ellipsoid (spheroid): GRS 19802 Oregon Custom Lambert Projection (Statewide Lambert – Feet International) Geographic Datum: 1983_NAD Units: Foot (international 1 ft - 0.3048 m) Geographic Coordinate System: GCS_North_American_1983 False Easting: 1312335.958 False Northing: 0.0 Prime Meridian: Greenwich Base Projection: Lambert_Conformal_Conic Central Meridian: -120.5 Central Parallel (Latitude of Origin): 41.75 Standard Parallel 1: 43 Standard Parallel 2: 45.5 II. DEFINING PROJECTIONS FOR UNKNOWN DATA SOURCES Arc Toobox provides tools for converting and defining projections for vector and raster data files. “Defining projections” creates a *.prj file that helps ArcMap complete “on-the_fly” projection transformations. The “project” tool, takes map data of a known projection, and reprojects into a completely new file format with a new projection system. “Define” projection tool simply designates a projection “Project” tool – transforms the data into a new coordinate system. NOTE: IT IS IMPERATIVE THAT YOU USE THE “DEFINE” AND “PROJECT” TOOLS IN ARCTOOL BOX FROM THE ARC-CATALOG PLATFORM (NOT IN ARCMAP) A. Defining projections for feature data sets with unknown source (creating *.prj files) a. Open the ArcCatalog Software Environment (do not use projection tools in ArcMap; the “on-the-fly” projection routines in ArcMap can cause confusion and run-time errors) b. Open Arctoolbox – pull down “Data Management” tools Menu i. Pull down Projections and Transformations menu 1. Pull down Features menu (for vector projections) 2. Pull down Raster menu (for images and grids) 3. Locate the “Define” projection tool on the list below features and rasters Examine the tools available for managing vector and raster-based data files and related projections. Explore the collective functions using the help menu to familiarize yourself with the objectives of the tools. ___________________________________ B. In-Class Exercise – Defining Projections for Data Source Files in Oregon / Monmouth Area Step 1. Download Class Exercise Data From Website and Save to Your Local Drive (H:/student folder) A) go to web site, look under the Lab Data Section - Map Projection Exercise i) sequentially click on the monmouth quad geology, roads, vegetation, and DRG *.zip files ii) save them to your network H:/ student folder iii) Use WinZip to Extract the Compressed Files3 a) use my computer - H:/ folder - click on *.zip file to extract NOTE: All of these map themes are from the Monmouth 7.5' Quadrangle. Step 2. Activate ArcMap Software A) In the “Table of Contents” , add the following "feature data source" shape files to the data frame: mongeo.shp, roads.shp, stateveg.shp B) 1 by 1, examine each theme, checking them on / off, rt-click and zoom to the active layer C) Check all themes on the table of contents, zoom to full extents. QUESTION: Why don't the themes overlay one another? Why is the full extent map view so screwy? D) Remove / delete all of the above themes from the table of contents / data frame. Step 3. add the following "image data source" file: monmouth.tif; add the following "feature data source" mongeo.shp (monmouth geology) A) Check both themes in the table of contents. Explore the data in both themes by zooming, overlaying, inquiring. QUESTIONS: What type of data is associated with the mongeo.shp map theme? Do both of these themes overlay one another properly in geospace? B) Now try adding the other vegetation and roads themes, do they properly line up in geospace? What is the problem with this set of data? Step 4. Your first goal is to define the projections for the Monmouth.tif, mongeo.shp, roads.shp and stateveg.shp files, and create related *.prj files A) Use "my computer" and click on the following text files to examine the metadata for these map themes: road_meta.txt, mongeo_meta.txt, and stateveg_meta.txt (these are metadata text files that provide information on the projections for each of the files) Task: list and the discuss the map projections used for each of the map layers, fill in the table below: File Name Projection Datum monmouth.tif ___________ ____________ mongeo.shp ___________ ____________ roads.shp ___________ ____________ stateveg.shp ___________ ____________ B) Now in your main project folder on the “H:\” drive, create the following 3 subfolders to organize your data according to projection type:4 a. UTM b. State_Plane c. Oregon_Lambert Sort, Organize / cut and paste the 4 data files into their respective folders according to projection, as you determined in 4A above. Step 5 – Download and save feature data sources of the state of Oregon, with known projections. You will use these now and in the future as calibrated, known “projection checks” for Oregon data in which you are unsure of the projection. A) go to web site, look under the Lab Data Section - Map Projection Exercise; locate the following links: • Shape File of Oregon Counties in UTM (use as projection check) • Shape File of Oregon Counties in Custom Oregon