ArcGIS Volume Measurement Tutorial
- 1. ArcGIS Volume Measurement Tutorial Mars-Based Data Developed by Alicia Hore (2012) Step 1: - Open a new Arc Scene Document (blank) - Click “Add Data” (button located along the top menu bar); add elevation file to be analyzed (ex. CandorBaetis DTM 25m Exported.bil) - Open the “Layer Properties” for the elevation file (right click elevation file in Table of Contents) o Under the “Base Heights” tab, choose “Floating on a Custom Surface” and choose the elevation file for surface o Click “Raster Resolution” and change the cellsize X & Y to an appropriate scale Raster Resolution can vary depending on the elevation file used. “Candor Baetis” has an actual resolution of 25m but Arc cannot load this high of a resolution due to the large size of the file so a lower resolution (65m) is used to help the program run smoothly. Try actual resolution first then change if needed. o Click ok to close the “Layer Properties” dialogue box Step 2: - Open Arc Catalog (thisstep can also be completed using the ‘Catalogue’menu located on the right-hand side of the ArcMap program) - Ensure that the folder being used to store the data is connected o ArcCatalogue: If not connected, click “Connect to Folder” button located second from the left on the toolbar at the top of the program; browse to the folder needed for storage. - Right click on the chosen folder listed in the “Catalog Tree” and choose “New: File Geodatabase” o Rename geodatabase to a unique name for the purposes of the project - Right click Geodatabase just created and choose “New: Feature Class” - In the Feature Class window, give your new Feature Class a name and choose the type of Feature Class to be made (Polygon needed for thisexercise); click next - Choose “Unknown Projection” for all Mars data (all projectionslisted relate to Earth surface projections); click next - Accept default “XY Tolerance”; Accept default “Configuration Keyword” - Add Name and Area to the “Field Name” column. Choose Text as the data type for Name and Float as the data type for Area; click finish. o Above step should look like the image to the right when finished.
- 2. Step 3.1 (Full Image): - Open new Arc Map project, “Blank Map” - Click “Add Data” and add the elevation file used in the Arc Scene project - Click “Add Data” and add the polygon feature just created in Arc Catalog (ex. Basin); click yes when prompted. - Under the “Customize” menu at the top of the Arc Map window, choose “Toolbars: Editor” - Click “Editor: Start Editing” on the Editor toolbar; click continue if prompted. - Ensure “Basin” is selected in the Create Features dialogue box on the right hand side; click Polygon in the bottom menu (Can choose whichever tool will work,for the purposesof this project, ‘polygon’ worksbest) - Using the Straight Segment toolon the Editor toolbar, begin drawing a polygon to define the area you wish to measure o Double click when the polygon is complete - Using the Edit Vertices button, the drawn polygon can be edited using the “Modify Sketch Vertices,” “Add Vertices,” and “Delete Vertices” buttons. - When done, click “Editor: Stop Editing” and save edits when prompted Step 3.2 (Clipped Image): - If specific portions of the image need to be measured individually, a slightly different process must be followed: o Follow the instructions from Step 2 to create new feature classes for each portion of the image needed (ex. If 5 portions need to be individually measured,create 5 new Polygon Feature Classes) o As in Step 3.1,draw polygons to indicate the separate areas that will be individually measured (the image below shows an example of how these separate areas can look) Straight Segment Edit Vertices Editor:Start Editing, StopEditing, Save Edits
- 3. Step 4.1 (Full Image): - Go back to the original Arc Scene project - Click “Add Data” and add the polygon feature that was just edited in Arc Map - Open the Layer Properties for the polygon feature o Under the Base Heights tab choose “Floating on a Custom Surface” and choose the elevation file as the surface. o Click Raster Resolution and type 65 for cellsize X & Y once again,the cellsize will differ depending on the data used o Under the Rendering tab,under “Effects”,ensure that “Shade aerealfeatures relative to the scene’s light position” is checked o Click ok to close the Layer Properties - The polygon feature is now draped over the elevation file Step 4.2 (Clipped Image): - If the image is being sub-divided for individual measurements,the original image must first be ‘clipped’ based on the feature classes made in Step 3.2 - Keeping the original image loaded into Arc Scene,click “Add Data” and add one of the new polygon feature classes made for the individual measurements - Using the search window (docked on the right hand side of the Arc Scene document), find and open the “Clip (Data Management)” tool o Parameters: Input Raster:Elevation file Output Extent: Polygon Feature class added Output: Choose appropriate file folder and a new name (ex. Clip Area Centre) Leave all otheroptions as the default settings - Once the tool has completed the clip, open the layer properties for the new clipped area and navigate to the Base Heights tab and choose “Floating on a Custom Surface” and choose the elevation file just created as the surface; change the cellsize to the appropriate dimensions
- 4. - Repeat the above steps for each sub-division that needs to be individually measured changing the Output Extent and Output file name to the appropriate area - Once all areas have been clipped and loaded in the Arc Scene document, a mosaic of the clipped areas is formed allowing for the user to see the extents of the measurements - For each of the polygons (used to clip the original image), open the “Layer Properties” and under the Base Heights tab,choose “Floating on a Custom Surface” and choose the appropriate elevation file as the surface (ex. If the polygon is “Clip Area Centre Basin,” the surface would be the elevation file “Clip Area Centre”) o Each of the polygon features will then be drapped over the appropriate area. Step 5: **The following steps are the same whetherthe full image is being analyzed or if the individual portions are being analyzed.Be careful to choose the appropriate Input Raster for each separate analysis, change the proposed maximumelevation if needed, and choose the appropriate polygon forthe mask - Using the search window (docked on the right hand side of the Arc Scene document), find and open the “Reclassify (3D Analyst)” tool o Parameters: Input Raster:Elevation file Reclass Field: Value Output Raster: Choose the file folder you have been saving in and create a new name for the file (ex. Reservoir, Reservoir Centre, etc) - The data needs to be reclassified for the program to properly measure the volume at the end of the exercise. For this particular data, the elevation was set to less than or equal to 3000m (the
- 5. proposed maximum elevation present in the area). With 3000m chosen, all of the area below this height is measured for volume. o In the “Reclassification” portion of the Reclassify toolwindow, the values of -4844 to 3000 are set as ‘3000’ and the values of 3000 to 4308 are set to ‘NoData’. The ‘No Data’ value portion is left unaltered. - Since we want only the values within the outlined area to be included in the analysis, a mask must be set for the Basin. o Click “Environments” located at the bottom right hand corner; Expand the “Raster Analysis” drop down menu o For “Mask,” choose the polygon feature appropriate - Click ok to close the Environment Settings dialogue box - Click ok to run the Reclassification - Open the Layer Properties for the Reclassification file (ex. Reservoir) and choose “Floating on a Custom Surface” under the Base Heights tab with the reclassification file as the surface o Correct the cellsizes to the appropriate scale - Turn off the original Polygon feature (ex. Basin). Step 6: - Use the search window to find and open the “Raster to Polygon” tool - Parameters: o Input Raster:Reclassification file create in Step 5 (ex. Reservoir) o Field: Value o Output Polygon Features:Choose the file folder you have been saving in and create a new name for the file (ex. ReservoirPoly) o Click ok
- 6. - Turn off the reclassification file in your table of contents and move the new ReservoirPoly above the reclassification file - Open the Layer Properties for ReservoirPoly o Under the Base Heights tab,click ‘Use a constant value of expression’ o Click the calculator button and in the Expression Builder,click the ‘grid_code’ field to add it to the expression window o Click OK to close the calculator, and click OK to close the Layer Properties box Step 7: - Use the search window to find and open the Raster to TIN tool - Parameters: o Input Raster:Elevation file o Output TIN: Choose the file folder you have been saving in and create a new name for the file (ex. ElevTIN) o Z Tolerance: 5 o Click OK - Turn off the Elevation raster file in your table of contents Step 8: - Use the search window to fine and open the Polygon Volume Tool - Parameters: o Input Surface:Elevation TIN file created in Step 7 (ex.ElevTIN) o Input Feature Class: Polygon file created in Step 6 (ex. ReservoirPoly) o Height Field: grid_code o Reference Plane:Below o Leave all of the other options as the default parameters o Click OK
- 7. - Open the attribute table for the Polygon file created in Step 6 by right clicking on the file in the table of contents and selecting “open attribute table” o A Volume and a SArea column were added to the table to show the total Volume (cubic metres) of the Polygon measured as well as the Surface Area (metres squared) of the feature