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Introduction to ArcMap for Water Resources Data

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Introduction to ArcMap for Water Resources Data Barbara Parmenter and Jack Melcher, revised: 9/15/2011 INTRODUCTION... 1 CHOOSING A HCDN STATION FOR WATERSHED MAPPING... 2 DOWNLOADING DATA FROM THE NATIONAL
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Introduction to ArcMap for Water Resources Data Barbara Parmenter and Jack Melcher, revised: 9/15/2011 INTRODUCTION... 1 CHOOSING A HCDN STATION FOR WATERSHED MAPPING... 2 DOWNLOADING DATA FROM THE NATIONAL MAP... 2 GETTING STARTED IN ARCMAP... 7 USING ARCCATALOG WITHIN ARCMAP TO MANAGE DATA UNDERSTANDING AND USING FOLDER CONNECTIONS CONVERTING THE STREAM GAGE GRAPHIC TO A GIS DATA SET ADDING NATIONAL LAND COVER DATA (NLCD) TO YOUR MAP ADDING THE NATIONAL HYDROGRAPHY DATA SET TRACING UPSTREAM NETWORKS USING NHD ADDING OTHER DATA LAYERS FOR CONTEXT CREATING A MAP FOR PRINTING SETTING UP A LAYOUT MOVING AROUND IN THE LAYOUT VERSUS THE DATA FRAME RESIZING AND MOVING THE DATA FRAME INSERTING A TITLE, NORTH ARROW, AND LEGEND OPTIONAL: ADDING A DATA FRAME TO SHOW A REGIONAL LOCATOR MAP SAVING MAPS UNDER DIFFERENT NAMES PRINTING OR EXPORTING LAYOUTS Introduction This tutorial introduces you to ArcMap 10, the GIS software program that we use at Tufts, and shows how to map relevant watershed data for a watershed of your choosing. Part of this tutorial involves acquiring data from a government data service for a stream gage and watershed of your choosing. Once requested, the acquisition process may take up to two days, so plan accordingly. A more typical time frame is an hour or two, but heavy use of the site may delay data delivery. If you wish, you can use a set of data that we have already downloaded for this tutorial the data is located on the GIS Center s network drive at S:\classes\CE 1 0112_Hydrology_Water_Resources under the Tutorial1_Data folder. The data are for HUC subbasin which straddles the New Hampshire/Maine border. Mozilla Firefox is recommended for use in this tutorial. Microsoft Internet Explorer, as configured in the computer labs, blocks the download of files from USGS. Data management for this tutorial: Make a HydroGIS folder with the following subfolders: Data, Temp Note: if you re in the GIS Lab, we suggest you use the H: drive Save your work frequently! ArcGIS tends to crash periodically, and there is no AutoSave feature. Choosing a HCDN station for watershed mapping Open a web browser and go to the Hydro-Climatic Data Network (http://pubs.usgs.gov/of/1992/ofr92-129/content.html) 1. Click on link for HCDN Streamflow Data 2. Choose a region 3. Choose a station name and in a text file, copy and paste the Station Number, station name, HUC code, and the latitude and longitude - look for a drainage area (DA) between 10 and 500 square miles e.g SACO RIVER NEAR CONWAY, NH :59:27N 071:05:29W (Note: use the above station information if you are using our pre-downloaded data sets) Downloading Data from the National Map Note: if you use our pre-downloaded data sets, you should skip this section and proceed to Section 4. The data sets are on the GIS Center s network drive S:\classes\CE 0112_Hydrology_Water_Resources under the Tutorial1_Data folder You will now download GIS data from the National Map, an online mapper and data distribution program from the USGS. In this section of the tutorial you will be downloading the following data sets for the hydrologic subbasin (HUC 8-digit basin) in which your stream gage lies: The National Hydrography Data set (NHD includes flow lines, water bodies, stream gages, and many other hydrographic data layers) A Digital Elevation Model (DEM - shows elevation and allows for watershed delineation and other hydrologic analysis) 2006 landcover (National Land Cover Data, or NLCD) 2 1. Open a web browser (preferably Mozilla) and go to the National Map web site (http://nationalmap.gov/) 2. Click on the link for National Map Viewers and select the current viewer: 3. Search for the coordinates of your selected HCDN stream station name (but now written as: N W (i.e., latitude comes first, no colons) 4. You will be zoomed into your stream gage point 5. In the top left corner, click on Overlays to open the Overlays panel (you may have to click twice to see the list of data layers as you see below) : 6. Expand Reference Polygons (click on + sign next to it) 7. Expand Hydrologic Units 8. Checkmark Subbasins to turn that layer on 9. You should see the HUC Code label come on the map - make sure it matches the HUC code from the HCDN station name that you recorded above 3 10. Click on Download Data (upper right corner of screen) 11. For Download Options, choose a reference area - select NHD Subbasin from the dropdown menu 12. Now click on your map near your stream gage 13. The resulting subbasin should appear in the selection results window click on See Available Data 4 14. Checkmark Hydrography, Land Cover, and Elevation 15. Click on Next 16. In the next dialog box, select the layers you see below clicking on Next each time you choose a data set: 5 17. Click on Add to Cart 18. Examine your Cart - you should have Hydrography, the National Land Cover data set for Land Cover, and the National Elevation Dataset in 1 arc second resolution 19. Click on Check Out and follow directions to Place Order (and write down the order number when it appears) 20. Check your for notice that data layers are available for download - some layers (with GeoTiff formats) will be ready immediately because they are raster data sets which are easy to extract. The hydrography data may take a while. 6 21. Create appropriately named subfolders within your Data folder (e.g. landcover, elevation, NHD) 22. When you get the initial back from the USGS, it will have download links to the land cover and elevation data sets. Download each data set in turn to your HydroGIS folder. Extract each data set to its appropriate sub-folder. Be careful to extract each data set to its correct subfolder! The example below is using Power Archiver: You will receive another when the hydrography data is ready. It is called NHD (for National Hydrograph Data). It will typically be ready in an hour or two but may take up to two business days. Getting Started in ArcMap Start ArcMap. If you are in the Tufts GIS Lab in Tisch Library, choose Start-All Programs GIS Applications - ArcGIS 10 ArcMap or click on the Desktop icon for ArcMap. 1. When the first dialog box comes up, highlight the option to start New Maps My Templates Blank Map and press OK 7 2. Choose Customize - Toolbars, and make sure that Standard and Tools are visible. 3. On the left side of the screen, you should see your Table of Contents area - right now it should only say Layers . 4. Go to File - Add Data Add Basemap choose USA Topo Maps and click Add Note: Adding a Base Map works inconsistently and requires an internet connection. And it can be slow. Be patient. If it doesn t work, try again. 8 5. In ArcMap, from Tools toolbar, click on Go to XY icon 6. Click on the units drop-down arrow as show below to choose your units to be Degrees- Minutes-Seconds: 7. Type the Stream Gage Station coordinates from the HCDN in the form you can paste them but make sure to edit them to substitute spaces for the colons, and also note that the West coordinate is Longitude, and the North coordinate is Latitude so that they have to be pasted in the reverse order of what you recorded from the HCDN network! 8. Click on the Add Point icon this adds a graphic point at that location. 9. Still on the Go to XY tool, click on the Zoom To icon this will center the screen over your stream gage. 9 10. In the Scale box of the Standard toolbar, select the 1:100,000 scale as shown your view will zoom to a 1:100,000 scale 11. The USGS has a 1:100,000 scale map series and that is what you are seeing now (1 inch on the map equals 100,000 inches in the real world) pan around the map at this scale. 12. Select the 1:24,000 scale this is another map series from the USGS (often called quad maps or 7.5-minute quadrangles maps, and is the one most familiar to natural resource managers and hikers) 13. Re-center your map on your stream gage Using ArcCatalog within ArcMap to Manage Data It s often useful for data management to have ArcCatalog open within ArcMap, and this also provides another way of adding data. 1. Within ArcMap, choose Windows Catalog from the main menu this adds ArcCatalog to your ArcMap session: 10 2. Click on the auto-hide pin icon in the top right corner of the Catalog box to pin it in place (otherwise it disappears after every interaction) Understanding and Using Folder Connections If you are in the Tufts GIS Lab, you will see that you have three folder connections already to H:, S:, and M:. The H: drive is your personal storage space. The M: drive holds data sets that Tufts has acquired for your use. And the S: drive holds class specific materials. The folder connection is a direct connection to these spaces in ArcGIS, and allows you to quickly access your data without navigating repeatedly through long folder paths. If you re working in the GIS lab, ignore the following directions and proceed to the next section. At home or other locations outside the Tufts GIS Lab, you will not have pre-set folder connections. You will need to add these yourself. The first step is to think about how best to organize your work, and create the folders necessary in your home computer using your Windows software for example, you might create a folder path in My Documents for Classes Hydrology GIS Tutorial. In the example below, I ve made a folder on my home computer under My Documents called Classes, and a subfolder path for Hydrology HydroGIS to hold my data. This is how I would create a Folder Connection to that folder in ArcCatalog: 11 Select only the folder! Don t drill down to the data itself! That way you have a connection to the folder holding all of your data, as you see below: Converting the Stream Gage Graphic to a GIS Data Set Your stream gage is going to be an important landmark for you but right now it is just a graphic on your screen. You want to convert this to its own GIS file, called a shape file, so that you have it stored permanently. 1. Customize Toolbars and add the Draw toolbar 12 2. From the Draw toolbar, choose Drawing - Convert Graphics to Features 3. Follow the graphics below - click on the folder icon and navigate to your HydroGIS project Data folder to save the file as Station_X.shp (where X is the station number from the HCDN database, e.g., Station_ ), and make sure it is saved as type: Shapefile. 13 4. Click Yes when asked if you want to add it to the map. 5. Save the mapfile (File - Save) call it Hydro Base Map1 and place it in your HydroGIS folder. A map file is a very small file that contains pointers to your data sets and remembers what you had up in your session. If you quit ArcMap at this point, the next time you start it, you can choose to start with this existing mapfile and it will automatically pop up the US Topo Maps and your stream gage point. Thus, map files are easy ways to save work. But beware - map files DO NOT contain the data layers, they only have references to the data layers. If you copied your Hydro Base Map1.mxd file and tried to open it on a home computer without the GIS data layers it is referencing, an ArcMap session would start and list the data in the table of contents but nothing would appear because it would not be able to find the data it is pointing to. 6. You can delete the graphic now that you have saved the point as its own GIS data set. Use the Select Elements tool on the Tools toolbar to select the graphic, then press the Delete key: 7. Right-click on your Station_X data layer in the Table of Contents and choose Properties 14 8. Click on the Symbology tab 9. Change the icon for the station into something that is more clearly visible on your map 10. Explore your area by panning around. If you lose your stream gage point, right-click on your Station_X data layer and choose Zoom to Layer. 11. When you are finished, choose File Save to save you mapfile. Adding National Land Cover Data (NLCD) to your Map The NLDC Land Cover Data will give you a spatial representation of land cover for the region of your watershed, based on 2001 satellite imagery and ancillary data sets. Before you use the data set you downloaded from the National Map, you need to understand what it represents. You can get this information at the Multi-Resolution Land Characteristics Consortium (MRLC) web site, as follows: 1. Go to the MRLC web site: 2. Go to Find Data - select National Landcover Database then Legend. This explains codes and color. You ll find these codes in the attribute table of the NLCD data that you downloaded earlier. 3. In ArcMap, click on the Add Data icon ( ) in the Standard Toolbar. 4. Add the Land Cover data set that you downloaded earlier from the National Map and unzipped (you will have to navigate to the folder where you saved it and drill down a 15 couple subfolders). 5. Click yes if asked if you want to create pyramids this speeds up display. 6. For now, ignore the Geographic Coordinate System warning by clicking Close on the warning box. 7. Your map should look something like this: 8. Right-click on the land cover layer in the Table of Contents and choose Open Attribute Table. 9. The Value column contains the land cover codes that you read about in the MRLC 2006 Land Cover Legend and the Count column gives you the number of grid cells that have a given code. 10. Close the attribute table 11. Right-click again on the land cover layer in the Table of Contents and choose Properties 12. In the General tab, rename the data set Land Cover 13. Review the information in the Source tab this is a raster data set composed of an array of grid cells. Each cell is 30x30 meters we know this from seeing the cell size (30,30) and, further down, the linear unit of the spatial reference is meters. If you zoom in close, you will see the individual cells. 14. If you haven t already, download the Land Cover 2006.lyr file here and save it to your project folder. This contains the same NLDC landcover classification schema you downloaded in Step 3, but is formatted to import into ArcMap. Save the layer file to your Data folder. (if you re working from a hard copy of this tutorial the layer file can be found by going to the Tufts GIS Center web site then to the Learning GIS section-online Tips and Tutorials-ArcGIS 10 Tutorials. 15. Still in the Properties interface, click on the Symbology tab. 16. Click on Unique Values on the left hand side. This shows you only the actual values that occur in your land cover data set. 17. Apply this layer file using the Import function 18. When you re finished, click on OK. Your map should look something like this: 17 19. Save your map file (click File-Save) Adding the National Hydrography Data set This section is to be done after you receive an message that your NHD data set is ready to download. The National Hydrography Data set (NHD) is the USGS most up to date digital version of mapped surface water features in the US. The data set is modeled in a way that allows for various types of analysis, including flow. For background about the NHD here: A geodatabase can contain feature datasets, which are groups of similar features. A feature data set then contains feature classes each feature class represents one type of feature. In the NHD Geo geodatabase, there are two feature datasets: hydrography and WBD (for watershed boundaries, or in some data sets, you ll see Hydrologic Units instead of WBD). The hydrography feature data set has several feature classes here are some of them: NHDFlowline The core linear network of the surface-water drainage system primarily consisting of streams, and artificial paths through lakes and other water bodies to model the flow of water. NHDWaterbody Polygons representing waterbody features such as lakes. NHDArea polygons primarily representing the area of hydrographic features. E.g., if a river is wide enough, on a topographic map it shows up as a filled-in blue area (polygon in GIS-speak) and not just a line. These are represented in the NHD data set by the NHDArea feature class. NHDPointEventFC Point Features addressed to the network. Includes stream gages and dams. The stream gage points include an attribute column with links to flow data from the USGS. HYDRO_NET_Junctions Nodes between NHDFlowlines used by the geometric network for flow navigation. You don t need to load this in your map, but ArcMap will use it for flow analysis later in this tutorial. 18 In this section, you will only need to add the NHDFlowline and the NHDPointEventFC feature classes, but if you have some extra time, you are encouraged to explore some of the other feature classes as well. 1. Check your for a message from NHDAuto er that the NHD data set is ready for download 2. Follow the link and download the NHD file to your data folder 3. Uncompress the data set 4. In ArcMap, use the Add Data icon ( ) to open the geodatabase 5. Navigate to where you unzipped the NHD data set and drill down to find the geodatabase 6. Double-click on Hydrography 7. Select NHDFlowline and and NHDPointEventFC and click Add 8. Again, ignore the Geographic Coordinate System warning by clicking Close on the warning box. 9. Because map files can sometimes get corrupted, save your map to a new name (File Save As) call it Hydro Base Map2 with NHD 10. Explore the two new layers what do they represent? 11. To see the NHDPointEvents more clearly, change its symbology to a larger symbol: 12. There should be an NHDPointEvent that represents your stream gage it may be on top of or nearby you gage station point. Locate it. 19 13. Click on the Identify icon and then click on the NHDPointEvent that represents your gaging station (if you don t have one, try finding another one) 14. Click on the FeatureDetailURL this will open a web site with real time data web site from the USGS for this gaging station. 15. Close the Identify window 16. Uncheck the NHDPointEventFC data layer in the ArcMap Table of Contents. You ve learned how to acquire data sets, how to add them to ArcMap, and a bit about the structure of the National Hydrography Data set. In the next section we ll work with the NHD more. Tracing upstream networks using NHD The NHD database structure contains embedded information about the direction and linkages of the flow network. ArcGIS has a tool, Utility Network Analyst, which can utilize this embedded information to trace upstream and downstream. 1. Make sure your NHD Flowlines are turned on in the Table of Contents 20 2. Click on Customize Toolbars and check mark Utility Network Analyst. 3. To see the flow direction, turn on Flow-Display Arrows 4. After examining the flow directions, turn off the Display Arrows 5. Zoom into the stream gage you located earlier (right-click on it in the Table of Contents and choose Zoom to Layer) 6. In the Utility Network Analyst toolbar, click on the down arrow next to the Add Junction Flag tool to expand the options 7. Choose the Add Edge Flag Tool 8. Click the NHDFlowline near the stream gage to set the analysis point turn off the land cover and US Topo Maps if you need to see the stream gage more clearly 9. From the Trace Task options, choose Trace Upstream 10. Click the Solve button to highlight all upstream flow lines 11. Zoom out to see the streams tributary to the gage you have selected Note: if you don t see any streams highlighted, you may have not placed the Edge Flag exactly right. Click on Analysis Clear Flags to clear your original flag, then zoom in and try playing an Edge Flag more carefully over your Gage Station Point: 21 12. Now choose Trace Downstream from the Trace Task options, click on Solve, and observe the highlighted flow path While these highlighted results are great for viewing, if we want to share these results with others or bring them up easily later, we want to save the result as a shape file. 13. Under Analysis choose Options 14. Change the Results format to Selection and click OK 15. Change the Trace Task back to Trace Upstream and click Solve. You should see something like this: You re going to create a n
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