Environmental Data Handling Guide for ENVR468: Fall 2008 using ArcGIS - Prof. Marc L. Serr, Study notes of Environmental Science

Download Environmental Data Handling Guide for ENVR468: Fall 2008 using ArcGIS - Prof. Marc L. Serr and more Study notes Environmental Science in PDF only on Docsity! General Guide to Environmental Data and ArcGIS For ENVR468: Fall 2008 TOPICS 1) Downloading Data from Internet Sources a. USGS Water Database b. EPA STORET (modernized & legacy) c. Air Data d. Health Data 2) Importing Data into ArcGIS a. Setting up ArcGIS i. Working directories ii. Relative path names b. Adding Shapefiles/Coverages i. Downloading from NJ DEP GIS website c. Adding XY Events i. Joining Tables d. Checking/Changing/Matching Projections 3) Manipulating Data within ArcGIS a. Categorizing Data i. Changing Layer Properties 1. Symbology 2. Quantitites ii. Selecting Specific Data 1. Selection within an Attribute Table 2. Selection by Location 3. Selection by Attribute (simple queries) 4. Converting Selection to Shapefiles b. Useful Tools i. Buffer Wizard ii. GeoProcessing Wizard 4) Saving GIS Data a. Layout View and Saving Graphics as JPEGs, etc. b. Saving Shapefiles and Projects 5) Exporting GIS Information for Other Uses (i.e. Matlab) a. Conversion Tools b. Projection Wizards c. Creating ArcINFO Interchange Files (e00) d. Importing to Matlab 1 Downloading Data from Internet Sources - USGS Water Quality Data: http://waterdata.usgs.gov/nwis - EPA STORET Water Data: http://www.epa.gov/storet/dbtop.html 1. For Data before 1999, choose the Legacy Database, after 1999, use Modernized NOTE: Some STORET Data and USGS Data may overlap but you should make sure of this when combining the data from these 2 sources See notes on surface & groundwater data acquisition for specific details - EPA Air Quality Data 1. AQS (Air Quality System) http://www.epa.gov/air/data/aqsdb.html 2. NEI (National Emissions Inventory) http://www.epa.gov/air/data/neidb.html - Environmental Health Data 1. CDC http://www.cdc.gov/nceh/data.htm 2 b. In ArcCatalog 1. Select the layer from the left window 2. Choose the Metadata tab in the right window 3. Select Spatial Attributes , the coordinate projection will show here 2. To change or define a coordinate system for a layer: a. In ArcToolBox: 1. Go to Data Management Tools  Projections & Transformation  Define Projection Wizard 2. In the dialog box, find the shapefile/coverage, etc. that you need to define a projection for and click NEXT 3. Choose Select a Coordinate System 4. Then choose Select to use a predefined coordinate system 5. Navigate through either the Geographic or Projected Coordinate Systems until you find the one you need. Usually you will determine which coordinate system to use based on other shapefiles or layers you are using in your project (look at the metadata) or perhaps from the literature 6. Once you have selected the appropriate coordinate system, it now becomes one of the attributes of your shapefile and you can match other layer’s coordinate systems to the one you just defined 4. Matching Coordinate Systems among layers a. Matching a projection or coordinate system is similar to defining a completely new projection for a GIS object b. In ArcToolBox: 1. Go to Data Management Tools  Projections & Transformations  Define Projection 2. Choose Select a Coordinate System then choose Import 3. Find the layer/shapefile/etc. that already has a projection defined which you would like to use and click Apply now both projections should be defined in the same way c. In ArcMap: 1. Go to View  Data Frame Properties  Coordinate System Tab 2. You can then select either a predefined projection or import a projection from another shapefile or coverage to match to the existing layer (using the Import button) NOTE: Making sure your projections are consistent first will save a lot of time later when you are combining layers, etc. 5 Manipulating Data within ArcGIS - Categorizing Data 1. Changing Layer Properties a. Right click on the layer that you are interested in  Properties b. Within properties you have several options (most useful are listed): 1. General: Change the layer name 2. Source: View coordinate system/source file 3. Symbology: View Data using categories/quantities/graphs a. Categories are useful when you have unique values b. Quantities are useful when you have data you want to aggregate and represent on the map 4. Fields: List the fields in your attribute tables 5. Joins/Relates: Lists any tables/layers that are joined to the current layer 2. Selecting Specific Data a. Selection by location 1. Go to Selection  Selection by Location 2. Follow instructions to select features from one layer that interact (i.e. intersect, contain, etc.) features from another layer b. Selection by Attribute 1. Go to Selection  Selection by Attribute 2. Use the simple query editor to define your selection a. double click the attribute on the left b. select an operator (AND/OR, >, < , =) and create an expression c. select a value for the expression c. Selection within a Table 1. Right click the layer and go to Open Attribute Table 2. You can click on a specific row in the table and select that feature it will then be highlighted both in the table and on the map view d. Saving Selections 1. Once you have created a subset of selected features from a layer you can save that selection as a new layer, to do this: a. right click the original layer you made the selection from b. go to Selection  Save Selected Features as a new Layer 2. A new layer may be automatically created when using Select by Loc. Or Select by Attribute, in that case just right click this new layer  Save as layer 6 - Other Useful Tools in ArcGIS 1. Buffer Wizard: Create buffers around features at a distance you specify 2. Geoprocessing Wizard: Lets you merge features in a layer, intersect layers, etc. 3. Geostatistical Analyst: Explore Data with graphs/charts 7