8.1 Objectives

This Lab contains 2 parts. In Part A, to be done in lab, you will:

1. Create a Digital Elevation Model from LiDAR LAS files
2. Construct a Geodatabase that can be updated by field observations;
3. Print map layouts and instructions for data collection to take with you to the field;
4. Export your project to an ArcPad v.10 project;

In Part B, to be done during the following lecture period, you will:

1. Learn procedures for capturing GPS points, lines and polygons with ArcPad 10 software;
2. In pairs, practice with a Trimble Nomad GPS receiver capturing the locations of polygons and lines on the Campus Main Building Mall.

8.2 The Problem and the Data

The Mason Mountain Wildlife Management Area (hereafter WMA), administered by the Texas Parks and Wildlife Department, is a state-owned, ~5300 acre former ranch principally dedicated to studying animal husbandry of "super exotic" African ungulates (Oryx, Kudu, Water Buck, etc.) in a Hill Country habitat.  Research into the ecology of the "central Texas Mineral Region" (a.k.a. Llano Uplift) and applications to wildlife management practices are also conducted there.  Access is restricted; entry is by permission only.  Geologically, the WMA is situated near the boundary of the western Llano uplift (Figure 1), where erosion of Cretaceous carbonates (green in Fig. 1) of the Edwards Plateau has exposed older Paleozoic and Precambrian rocks (blue and pinks in Fig. 1) of the Llano Uplift beneath.  The wide variety of rocks exposed here and extensive outcrops of the Precambrian granite of the Katemcy Pluton (Fig. 2) make this a nice location for studying the geologic history of the uplift and the products and processes associated with magmatic intrusions. 

Figure 1. Generalized geologic map of the Llano Uplift region, showing the location of the Mason Mountain Wildlife Management Area in Mason County.

Figure 2.  Generalized geologic map (data from Geologic Atlas of Texas, Lllano Sheet) of the Mason, TX area, including the WMA.  We will not be camping in the location shown on this map.

The goals of our weekend field trip are to two fold:

1. Map the distribution of Precambrian rock outcrops.  These cannot be mapped with high fidelity from areal photographs because of masking by vegetation, but are easily recognized from bare earth Lidar digital terrain models (more below).  The digital outlines of outcrop polygons allows for, among other things, an accurate estimate of the area underlain by vegetation vs. rocks within some of the high-fenced pastures of the WMA.  This is an important statistic for game management studies.  Subtracting the sum of the rock polygon areas from the total pasture areas will give this statistic.

2. Map and measure the orientation of fracture/joint sets and planar dikes in granite.  Note relative ages where possible.  These data are needed to better address questions about the age and orientation of stresses responsible for extensive fracturing near the southern margin of the Katemcy Pluton.  Our high resolution Lidar terrain models will reveal a pattern, but field data are required to interpret it.

   Data 

The GIS lab portion (Part A) uses the following data:

• UTM zone 14 NAD83, LAS-format, Airborne LiDAR files acquired during flights in 2007, provided by the Texas Natural Resources Information Service (TNRIS).  These were ordered and collected from their Austin office for the cost of a 50 Gb flash drive;
• a UTM zone 14 NAD83, 0.5 meter-resolution, 2008-2009 digital orthophoto (NW quarter of the Purdy Hill Quad.) from TNRIS;
• Shapefiles of rock units, faults, contacts, roads, fences, etc., some created by David Kilventon for his 2006 senior thesis map of the WMA, others from my own work;
• edited NAD83 National Hydrological Dataset (http://nhd.usgs.gov) ) files for water bodies, springs and flow lines

**Download the Lab_7_data folder to your flash drive, NOT YOUR NETWORK STORAGE.**  This file contains over 4 Gb of data and may take up to 5 minutes to download.
 

8.3 Working with LiDAR data in ArcGIS 

LiDAR data are fundamentally clouds of points ("point clouds") with XYZ coordinates and attributes. They are commonly stored and distributed in LAS (LASer) format files, a non-propriety format that has gained wide acceptance in recent years.  ArcGIS have extensive tools for importing and working with LAS files.  Our goals for this part of the lab are to:

• Import LAS files into ArcGIS and examine their properties
• Create a raster digital terrain model ("DTM") from these vector files

1. After checking to be sure that the Spatial Analyst and 3D Analyst Extensions are checked on in a blank ArcMap document, open the ArcCatalog window inside of ArcMap, right-click on the Lab_7_data "LiDAR" folder and select "New", create a "LAS Dataset" and rename it MMWMA.lasd.  This creates a container into which we can import LAS files.  A "LAS Dataset" (.lasd) has special properties that allow us to examine some of the unique features of LiDAR data and is required for some LAS processing tools.
2. Add the six LAS files (each is a tile of a single large area and has a file name that ends with .las) to this new LAS Dataset by right-clicking on the LAS Dataset icon, selecting "Properties...", the "LAS Files" tab and the "Add Files..." button (shown below).

3. Examine the Properties of the imported files. Note that each file contains 26 million points - we will be working with over 150 million points in this exercise (!) - that are spaced at about 0.63 meters (as shown below).  The maximum (Z Max) and minimum (Z min) elevation of the points in each file is also listed.

4. Open the "Statistics" tab and click the "Calculate" button - this may take some time... there are over 26 million points (!) in each of the files.
5. As shown below, the result provides Statistics on two important parameters.  This will be important later - pay attention as you read on...

LiDAR data consist of multiple "Returns" (upper left table): light pulses that bounce back to the instrument. A "return" is a specific arrival at the instrument from a single laser pulse.  For each pulse, these are classified by whether they return quickest ("First returns") or at successively later times (Second, Third, Forth, etc.).  As shown in the statistic table, of the 158,393,951 returns, about 50% are first returns (also classed as "First of Many") and 50% are later ("2nd", "Last", "Last of Many").  More recently acquired data will often contain a more detailed classification of returns - these 2007 data, in LAS 1.1 format (see first table), contain only two classifications, making them less useful for some applications.

During post-processing, most returns are assigned a standard Classification Code (middle table) based on the origin of the return.  The distinction between return number (i.e first, second, etc.) and Classification code is important - it is easy to understand that for partially vegetated areas some first returns will come from the ground whereas others will from the tops of trees.  We are interested in returns that are classified as ground returns - coded 2.  For this dataset, points with ground returns are least abundant (~21% of all data); note that all other returns (~79%) are "Unclassified" (code 1).  Again, more recent datasets commonly contain classification for 4 or more additional categories: i.e. water, vegetation, buildings, etc.

The strength or Intensity of returns (middle table) are also measured (on a scale of 0 to 65,535) - some pulses come back strong, some weak.  Strong returns come from highly reflective surfaces, weak from surfaces that absorb some of the laser pulse.  Minimum and Maximum Intensity measurements are listed for each classification.

6. Click "OK" to store the statistics. 

7. Drag the MMWMA LAS Dataset from ArcCatalog into a blank Arc Map window.  You have just loaded the entire point cloud, all ~158 million points!

8. ArcMap shows only the red outlines of each of the six data tiles (this keeps redrawing times reasonable) until you zoom to a specific area.

9. Zoom into the lower right corner (at a scale of 1:10,000 or greater) of the upper middle tile.  Your screen should look similar to image below.  You are looking at a two dimensional view of a point cloud, color coded by elevation - the ArcMap table of contents shows the range of elevations (in meters) represented by each color.  White represents areas of no points.

9. Open the LAS Dataset toolbar (Customize>Toolbars>LAS Dataset), which contains a variety of options for viewing and manipulating point clouds.



If the toolbar is grayed-out, you will have to turn on the Spatial and 3D analysts extensions, as indicated in the step 2 above.

10. Want to see something astounding? Use the Profile Tool (second from right on the LAS Dataset toolbar) to construct a short vertical profile (a cross section) through the point cloud.  A tool tip, visible when hovering the mouse over the tool, explains how.  These are unfiltered points, so we are viewing returns irrespective of Code Classification (tree tops clearly visible!).  We won't spend much time with this tool but it's just too cool to ignore!
  Explore the other tools on this toolbar - they provide very powerful ways to view and interactively filter LAS point clouds.  If they don't seem to work, try sampling a smaller area.

11. Can't resist one more trick with this toolbar... create a surface elevation model (a TIN) with the Elevation tool on the toolbar (see below) by zooming in or out of your Map.

The maps/profiles created with the LAS Dataset toolbar are visualizations created on-the-fly, not permanent products.  As such, they are of limited use for analysis.  We would like to create a permanent raster dataset from this LiDAR (vector) point cloud - specifically a high resolution, "bare earth" Digital Elevation Model (DEM; nomenclature varies - LiDAR-derived bare earth rasters are commonly referred to instead as Digital Terrain Models (DTMs)).  This will require a tool from ArcToolbox.

12. Using the Search window in ArcMap, search "LAS to Raster" for the tool needed for this conversion.
13. IMPORTANT - Before running this tool make sure a) that you are zoomed completely out and can see the red outlines of all of the data tiles in ArcMap; b) that the LAS Dataset Toolbar has the "Filters" tool drop-down set to "Ground" and the Point tool drop-down set to "Elevation".  These choices will be recognized by the "LAS Dataset to Raster" tool in ArcTool box if we take care to choose the ArcMap layer as the Input Dataset and not browse to and choose the original LAS Dataset.
     
14. Open the "LAS Dataset to Raster" tool from ArcToolbox or the Search window.  If not already shown, show the Help for this tool. USING THE DROP-DROWN ARROW AND NOT THE FOLDER ICON (see graphic below), select MMWMA.lasd as the Input the LAS Dataset

• name your output raster MMWMA_DTM, to be stored in your LAS_WMA_2007 folder of Lab_7_data folder
• Value Field is ELEVATION,
• Interpolation Type is Binning with "MINIMUM" (this is a bare earth model...) as the Cell Assignment Type and NATURAL_NEIGHBOR as the Void Fill Method. 
• DO NOT CLICK OK YET -we need to specify the raster resolution (cell size), which requires some thought.  The raster cell size should never be smaller than the point spacing of returns.  As seen in the statistics, the average return spacing is about 0.6 meters. This is for all returns, irrespective of classification.  We are using Class 2 (ground returns) only, not all points, so the spacing for these returns may be significantly greater (3x to 4x greater- not all points will have ground returns).  A conservative approach for a bare earth DTM is to set the raster cell size to ~ 3 times the average return spacing.  For our data this means about a 2 meter cell size, SO SET THE "Sampling Value" TO 2.
• Z Factor is 1. Click OK. This will take a few minutes...

If all went well your DTM should look like the one below.

This new DTM will be easier to visualize in shaded relief.

• Using the Search window, find the Hillshade tool in ArcToolbox and create a Hillshade.  Your Hillshade should resemble the one below.  Take some time to explore this at higher magnification - it's an amazing product!
• Load the hillshade_sm file into your ArcMap project.  hillshade_sm is a ~10m resolution hillshade created from a National Elevation Dataset (NED; more on this dataset in a later lecture) 10m DEM.  NED data are not derived from Lidar measurements.  As illustrated in the comparison figure below and from your own observations, the difference is dramatic.  Fracture patterns that are, at best, obscure in the ~10m data are clearly visible is the 2m DTM.

The 2m DTM hillshade exceeds the boundaries of the WMA and is a ~56 Mb file stored in uncompressed ESRI grid format.  We would like a smaller compressed file for our handheld field units.  We can make one by clipping the file to the WMA boundary and converting the result to a JPEG image.  To do so:

• Load the "WMA_boundary" file into ArcMap;
• Use the "Extract by Mask" tool in ArcToolbox to clip the DTM hillshade to the WMA boundary polygon.  In so doing, you will have to choose a file name less than 13 character; I used "clp_hshade"for my clipped version.

• This new file is also in ESRI grid format but is now ~32 Mb (verify this examining the file Properties>Source tab).  This file is still too large.  To compress this new raster:

  1. Right click on the file name in the ArcMap table of contents, select "Data">"Export data..." to show the following Export Raster window:



 Fill in the fields with the values shown in the red box above, making sure you save this to a place where it can be easily retrieved, and click "Save".  This will create a 2m resolution, JPEG compressed raster, saved in Geotiff format.  Through these processes, we have reduced the file size from ~56 Mb to about 8 Mb without appreciably affecting the utility of the hillshade!  This new Tiff file is now small enough to store and render on our old handheld units.

8.4 Constructing a Preliminary Map for Field Work

Base map data for this project are available in shapefile format, but we will find it useful to build a Geodatabase so that we can establish domains for data entry.  We will be collecting data with ArcPad software, which permits the capture of GPS positions for points and vertices and uses forms for entering attributes while in the field.  By using coded value domains in our geodatabase, we can create drop-down menus for our forms, a far easier way to enter attributes than pecking letters with a stylus on a virtual keyboard.  Recent versions of ArcPad (7.0 and above) also allow the option of "checking out" Feature Classes from a database for field editing with ArcPad, then checking them back in when finished.  When it works properly, this is a very efficient way of editing a field-based GIS, eliminating the need to update existing files by appending, merging or otherwise editing them to conform to new field data.  You have already done many of the steps below in Lab 4. Refer to it if you've forgotten aspects of Geodatabase Feature Class and Domain creation.

1. Open ArcCatalog and browse to your Lab_7_data folder.
    
2. Create a personal geodatabase called "Mason_Mt_WMA_XX" (where XX is your first and last initials) within your Lab_7_data folder.
    
3. Right-click on your new geodatabase and "Import" all of the Feature Classes (no rasters!) in the Lab_7_data folder (and subfolders) into the geodatabase. The spatial reference for all of these feature classes is NAD83, UTM zone 14N, and they will import as such.
    
4. Geodatabases can not hold layer files (these files contain the symbology for the feature classes you just imported) yet we would like to use the layer files to symbolize the new geodatabase feature classes. To do so we must reset the source for the layer files.
   
   Right-click on a layer file icon, select "Properties...", click the Source tab then the "Set Data Source..." button and reset the source by browsing to the appropriate Feature Class in your geodatabase. Do this for all Feature Class layer files (but not raster layer files).
    
5. What about the raster files?  The Lab_7_data folder contains two very high resolution DOQs (one multiband color, one single band panochromatic) with associated layer files and our newly created Lidar 2m hillshade raster; should we import these into the geodatabase? In this case the disadvantages of doing so outweigh any advantage. In particular, the color DOQ is a large MrSID file that would get much larger when uncompressed and stored in IMG format, which is the format required by the geodatabase. There is no real advantage to doing this, other than having everything in a single container, and we are left with a file that is >150 Mb. We could instead create a geodatabase raster index (see Help files on this topic), but for the few rasters we will work with this also provides no real advantage. We will keep the rasters separate from the geodatabase for these reasons.
    
6. Time to create the empty Feature Classes that will contain the GPS-derived points lines and areas... 

1. Before doing so, it is good practice to create a Feature Dataset that will contain the new Feature Classes (this is similar to creating a feature dataset when we digitized in Lab 4; we are digitizing in the field using a GPS instrument).  To do so, right-click on the Mason_Mt_WMA geodatabase icon, select "New...", then create a new Feature Dataset called "Geology".  SET THE SPATIAL REFERENCE OF THE FEATURE DATASET TO NAD83 UTM zone 14N, SET THE "Z COORDINATE SYSTEM" TO <None> AND ACCEPT THE DEFAULT XY TOLERANCES. (Note for outside users: the procedure for doing this in ArcGIS 9.1 is somewhat different.  See an example here).
   
   
2. Now we can create the Feature Classes; right-click on the Geology Feature Dataset icon, select "New...", then create new Polygon, Line and Point Feature Classes (named Polygon_XX, Line_XX and Point_XX, where XX is your first and last initial).  Do this step 3 times, one for each Feature Class, being sure to change the Geometry type [polygon, line, point] to match the Feature Class and checking the Geometry Properties box on to allow "Coordinates include Z Values" as shown below.

3. The polygon feature class will be used to store the GPS-derived outline of granite outcrops and any other features that are polygons.  We need an attribute field that records the feature being mapped (e.g. "granite", "pegmatite" or “other”) that can be entered as we collect the data.  So... add two Text fields to the polygon feature class, one called "FEATURE" and another called "COMMENT". The length of the FEATURE field should be 9 and the COMMENT field 30.  Leave all other Field Properties blank for now.  Please use these precise field names, including capitalization, for this and all other feature classes. Merging and appending files from different GPS receivers is much easier if everyone uses exactly the same field names and properties.
    
4. Create a Domain (by right-clicking on the Mason_Mt_WMA geodatabase icon, then Properties...) called PLY_TYPE, (Field Type is Text) that is a coded-value domain containing the coded values of "granite", "pegmatite", and "other" (see Lab 4) and then attach this domain to the polygon attribute field FEATURE (again see Lab 4).
   
   
   1. The line Feature Class will be used to store rock unit contacts or outcrop boundaries that can't immediately be seen to close on themselves (i.e. can’t be mapped as polygons). The attributes that will be recorded and the new fields to create are:
      

      i. 9-character text field, called  "FEATURE", that will contain coded values from a text Domain called "LN_TYPE" of "contact", "outcrop" and "other".

      ii. 7-character text field, called "SYMBOL",  that will contain coded values from a text Domain called "Symbol" of "solid", "dashed" and "dotted".

      iii. 30 character text field, called "COMMENT", without an attached domain.

      
      
5. Create these new Fields and their Domains with the above coded values and attach the Domains to the Fields, as in steps c and f.
   
   
6. The point Feature Class will be used to record the location of features too small to recorded as polygons and for strike and dip measurements. We will need fields for:
7. 
   
   1. 10-character text field, called "PT_TYPE", that will contain coded values from a text Domain called "PT_TYPE" of "joint", "foliation", "bedding", "dike" and "other".
   2. 3-character short integer field (Precision equals 3), called "STRIKE", that will contain coded values from a short integer Domain called "strike" of every third integers between 0 and 357 (i.e. Codes of 0, 3, 6, 9, 12 etc. with Descriptions of 000, 003, 006, 009, 012, etc. to 357; yes, all 120 values).
   3. 2-character short integer field (Precision equals 2), called "DIP", that will contain coded values from a short integer Domain called “dip” of every second integer between 2 and 90 (i.e. Codes of 02, 04, 06, etc., with Descriptions of 02, 04, 06 etc.; 44 values in all).
   4. 30-character text field, called "COMMENT", without an attached domain.
   
   
8. Create these new Fields and their Domains with the above coded values and attach the Domains to the Fields, as in steps c and d.

Congratulations, you have now completed the database you will need for this project.

8.5 Making Field Maps

1. Open ArcMap with an empty map document and load all of the LAYER FILES (not the Feature Classes), including the layer files for the DOQ and Hillshade.  If this doesn't work, you skipped Step 5 above.
   
   
2. Load your empty polygon_XX, line_XX and point_XX Feature Classes you just created and move them to the top of the Table of Contents if not already there.
   
   
3. Order the remaining layers so that the Hillshade is at the bottom, the DOQ is second from the bottom, and all remaining layers above these.
   
4. Set the Display Properties of the rock units and the outcrop polygons to 50% transparent.
   
   
5. Zoom to the WMA boundary layer, reset the reference scale, and SAVE THE MAP document to your Lab_7 folder.

Switch to Layout mode and make a map with a 50 meter UTM grid, scale bar, north arrow, name, etc.  Print two maps, one with the hillshade layer turned on and another with the hillshade off but the DOQ on. The scale should be ~ 1:10,000 to be useful; you will have to tile the map onto a few pieces of paper to cover the area of interest (Margo will tell you how much of the area to print), which is within the portion of the WMA that is within granite southeast of Mason Mountain and along the western boundary within granite.

 Bring these maps with you on the field trip.

8.6 Trimble Nomad and ArcPad v. 10

GPS data collection using the Trimble Nomad units is done with ArcPad software.  ArcPad is a streamlined version of ArcGIS that is equipped with very easy to use GPS capture tools.  ArcPad 10 is installed on the classroom computers and our field data collection units.  Version 10 is a major revision from earlier releases.  Before getting a little ArcPad practice, we first need to convert the ArcGIS map document file into an "ArcPad Project".  An automated tool exists to do so, which converts most rasters to jpeg images, the geodatabase to an ArcPad exchange format database (.AXF), and makes data entry forms from the domains for each Feature Class.  We can "check out" the empty Feature Classes for editing then, upon return, "check in" the same, permitting the software to automatically update the geodatabase!

An important note about ArcPad versions:

• ArcPad 10 represents a significant departure from earlier versions (i.e. 8.x and below).  "ArcPad Projects" created for ArcPad 10 will not run on 6.x software, and vice-versa.  The ArcMap toolbar for creating ArcPad projects in versions of ArcGIS 9.1 and higher contains separate tools for creating ArcPad 8.x and 6.x (or lower) projects.  It is thus important to know which version of ArcPad is installed on your field data collection units.  Our Trimble Nomads and Xplore tablet PCs are currently running ArcPad 10, as are the computers in the lab. 

A. Preparing the Map Document for ArcPad (version 10).

1. Open your map document.
    
2. Switch to Data View mode (if you're in Layout mode) and zoom to your Hillshade layer.  This is an important step!
    
3. Make sure the "Point" and Rock Unit contacts Feature Classes are present in the Table of Contents of the map.  These have coded-value domains already built that will allow use of ArcPad data entry forms.  These are the files you will populate with GPS measurements.
    
4. Change the symbology of these files to colors/symbols that will be recognizable on both a white background and the DOQ.  Red works well, as does light blue.  This is much easier to do now than later in ArcPad.
    
5. If not already on, Turn on the ArcPad Data Manager toolbar (Tools>customize...) shown below.
    

6. On the ArcPad toolbar, click the "Get Data for ArcPad" button.
    

7. Click the black arrowhead to the left of your "Points_XX" Layer and choose "Checkout for disconnected editing in ArcPad>data based on defined extent".  Do the same for the Line_XX and Polygon_XX layers.
8. For all other vector layers choose "Export as Background data (to Shapefile)>Make Read Only"
9. The only raster file we will export is the clipped 2m Lidar hillshade. For this layer choose "Export as background using the original raster".  Do not export any other rasters, they are too large to open on our handheld units, even when compressed!
10. Click Next.

12. The next window, "Select Picture Options", is not applicable to this project; Click Next.
    
13. The final window lets you set the spatial extent (current display extent or full extent of the layers), lets you select whether to limit the fields to those that are visible in the attribute tables and the features to those specified in the layer's definition query, lets you specify a name for the folder that will store the data, and lets you create an ArcPad map file (the equivalent of an .mxd file) for the data, as shown in the "Get Data For ArcPad" screen capture below.
     
14. Enter a name for the folder, e.g. "ArcPad_WMA_XX" (where XX are your initials) and a Map Name that includes your last name or initials (e.g. WMA_XX).
     
15. Making sure first that your display shows the entire area of interest (i.e. you are zoomed to the area of interest), make the selections shown in the figure below, setting the "Where do you want the folder to be stored?" to an appropriate location on your flash drive.

16. Click Finish and wait for the data to be created.
     
17. With help from me or Margo, transfer your new "ArcPad_RR_XX" folder to your Trimble Nomad (these will be shared, but each partner can load a project). The Nomad units have a folder called "My Documents" that should be used for all ArcPad data and files.
    
    
18. Print a color copy of the PDF file "ArcPad Quick Reference", in color, from All Programs>ArcGIS>ArcPad 10>Help>ArcPad Quick Reference.  You will find this exceptionally useful for Part B of this lab, and for the field trip.

PART B  

Practice with ArcPad in the field

8B.1 Using ArcPad - some practice with the basics

Editing in ArcPad is, in most ways, much simpler than Editing in ArcGIS.  The basic concept is the same in both - data are entered into a file that is open for editing.  Below are a few of the basics.  A complete description of the software can be found in the ArcPad 10 folder in the class folder.

1. On a classroom computer, open ArcPad 10 from the Start Button>All Programs menu in Windows. If needed, enter one of the license codes available in the Lab_7_data folder.
    
2. Click the folder button at the top of the ArcPad window and select  "Open Map", then browse to your ArcPad map file, the one with the ".apm" extension, in your "ArcPad_RR_XX" folder.
   
   
3.  Five toolbars are immediately available (called Main Tools, Browse Tools Edit Tools Quick Capture and Navigation), though only one at timeis displayed  (this saves real estate on small screens).

4. Click the Main Tools icon (on the left in the figure above) and then select the Layers icon to open up a Table of Contents, like that on the left below.  The diagram on the right, from an earlier version of ArcPad, has many of the icons labeled.

5. The check boxes on the left in the "eye" column turn layers on and off for viewing.  The check boxes in the "pencil" column turn layers on and off for editing.  This is similar to setting the "Target" of the editing toolbar in ArcGIS, except that in ArcPad more than one layer can be open for editing at a time.  In the Table of Contents to the right above, none of the layers are open for editing. In the table of contents on the left above three layers (Point, Line, Polygon) are open for editing. Finally, the check boxes below the Info icon (i) make layers available for query.  Layer Properties can be accessed by an icon on the right, as can other options denoted by icons that should be familiar from ArcMap.  The column with the "rocket ship" icon at the top is the QuickDraw mode; checking boxes here allows the different layers to be drawn to different "coarseness" so they will render quicker on screen.  The QuickDraw mode is accessed from the Editing Toolbar.

6. Turn on the "Point_XX" layer for editing and close the Table of Contents.

7. Turn on the Edit toolbar by selecting it from top row of icons, as shown below.

8. The function of the edit tools are shown in the figure below.  This is the most important toolbar for the field work this weekend.  Learn it.

To add a point to the map, Click the pencil tool, select the layer you want to edit, click the "Capture a point feature" button, (Capture of polyline or polygon features, if open for editing in the TOC, can be selecting from the drop-down menu below the "capture a point" feature icon). Then click a location on the map.  A data entry form should then open, allowing you to select the feature name from a drop down list.

To do outdoors: To add a GPS location as a point, click instead the "Capture a point using GPS" button. (When the GPS is active this button is not grayed-out.)

9. To add a line, click the Pencil icon, select the polyline feature class you want to edit, click the drop-down arrow below to the "Capture a point feature" button, and select "Polyline".  Click on the map where you wish to place a polyline vertex, click and drag on the next spot where you want a vertex, and continue this process until finished.  The line is not completed until you click the "Proceed or complete feature" button at the bottom of the ArcPad window (shown below).

10. To do outdoors: To add GPS vertices to a polyline, as above, click the "Capture a polyline" button (beneath the capture a point button), click the "Add a single vertex from a GPS position" button and continue clicking this button every time you want to add a vertex to the line.  To finish the line, click the "Proceed or complete feature" button, the green arrow icon. The line is not completed until you click the "Proceed or complete feature" icon.
    
    The GPS must be activated before the GPS buttons are available. 

11. A similar procedure is used to capture polygon vertices with and without GPS.

12. You can delete features by selecting them with the Arrow button (shown above) and then clicking the "Edit vertices" button.

13. Practice adding and deleting lines, points and polygons to the map.  Name the features test1, test2, etc. so that, if needed, you will be able to recognize and delete them later.

14. Browse the ArcPad manual in the digital books folder, particularly the sections on editing.  Download and print the ArcPad Quick Reference page.

15. Before loading your ArcPad folders to the field GPS units, clear each of your test features, or don't save your project after editing.

8B.2

1. Before our field trip, you need practice using ArcPad with a GPS. An ArcPad project for the Main Building area, identical to the ArcGIS project you constructed in Lab 6, is loaded on all instruments.  Take your instrument outside, open the Main Building project, and practice capturing lines, points and polygons using the ArcPad GPS tools described above.

2. Specifically, capture the features listed and labeled in the photo below.

• Points: Points at the two flagpoles.
• L1, L2, L3: Polylines with at least 3 GPS vertices at the edges of sidewalks.
• P1, P2: Polygons outlining grass areas - capture the vertices of the 4 corners with GPS. s - capture the vertices of the 4 corners with GPS.

You're done.