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Global Mapper is a viewer capable of displaying the most popular GIS raster, elevaƟon, and vector datasets, allowing users to easily view, edit and export their data in mulƟple formats. w w w .li br ar y. ca rle to n. ca /fi nd /g is Page 1 Global Mapper Loading a DEM into Global Mapper Load a Digital ElevaƟon Model (DEM) View the DEM in 3D Create an elevaƟon profile graph Export the DEM to a 3D mesh for use in AutoCAD Generate contours from the DEM Export the contours to .DWG or .SHP formats When you first open Global Mapper, it will look like Figure 1. Click on the first opƟon to “Open Your Own Data Files”. In the file browser window that pops‐up, navigate to the DEM file you wish to open. AlternaƟvely, in a separate file directory window you can navigate to your DEM file and click and drag it into Global Mapper. The DEM should load as shown in Figure 2. The legend on the leŌ side shows the eleva‐ Ɵon colour ramp. Important: Seƫng the ProjecƟon ensures proper measurements Click on ”Tools” then ”Configure” and ensure that the correct projecƟon is set. The projecƟon used should be UTM and correspond to the correct zone. To determine the appropriate UTM zone, go to the index: hƩp://www.library.carleton.ca/interacƟve‐indexes and double click on the “UTM_Index.kml” file to open in Google Earth. The last 2 digits of each index corresponds to the UTM zone. Figure 1: the opening window of Global Mapper Global Mapper supports viewing of many popular data formats, including: DEM, DGN, DXF, ECW, MrSID, ESRI Shapefiles, E00, MapInfo MIF/MID, MapInfo TAB/MAP, SRTM, JPG, PNG, BIL, BSQ, BIP etc. Figure 2: a loaded DEM showing the City of OƩawa Control Centre Zoom in/out Measure Pan IdenƟfy Show 3D view 3D ElevaƟon Profile Figure 3: The Main Tools on the Toolbar This help guide will show you how to: Page 2 Global Mapper Viewing the DEM in 3D When viewing files with an elevaƟon component, such as DEMs or LiDAR, you can click on the “Show 3D View” buƩon (see Figure 3 on previous page). This will open an 3D View window where you can pan, zoom, and rotate the view using the by clicking on the tool icons shown here: Figure 6 (below): the elevaƟon profile graph showing changing elevaƟon over distance. Creating an Elevation Proϐile An elevaƟon profile graph will show you the elevaƟon in a cross‐secƟon of the DEM., as shown in Figure 6. To start, click on the “3D ElevaƟon Profile” buƩon (see figure 3 on previous page). This will pop‐up a “Tip” box, to which you can just click “OK” to. With the cursor, click to draw a line across the DEM for which you are interested in seeing the elevaƟon pro‐ file for (Figure 5). LeŌ‐clicking will stop drawing your line and the elevaƟon path profile window will pop‐up. Figure 4 (leŌ): a 3D view of GaƟneau Park from the OƩawa DEM. Exporting a DEM to a 3D .DXF Mesh for AutoCAD A 3D surface model for use in AutoCAD can be created by exporƟng the DEM into a DXF mesh. The first step is to roughly zoom into the area you are interested in exporƟng. Try not to take too much excess area, in order to speed up the drawing process of the mesh. Once you’re zoomed into your area, click on “File” then “Export ElevaƟon grid Format”. This will pop‐up the “Select Export Format” window (Figure 7). From the drop‐down menu, select the “DXF mesh” file format; then click “OK”. ConƟnued on next page….. Figure 7 : the Select Export Format pop‐up window Figure 5: the elevaƟon profile cross secƟon line Page 3 Global Mapper Next, a “DXF Mesh Export OpƟons” box will appear (Figure 8). You can change the pa‐ rameters to whatever suits your dataset, but remember to check ON the “Interpolate to Fill in Small Gaps in the Data”. Secondly, click on the “Export bounds” tab, then the “Draw a Box” buƩon to more spe‐ cifically select your area to export by drawing a box in the pop‐up window. Everything inside this box will be exported to your mesh. Once you press Ok, a file browser window will pop‐up. Locate your output folder and give the mesh an appropriate name. The exporƟng will begin...this may take some Ɵme depending on the size of your area. Exporting a DEM to a 3D .DXF Mesh for AutoCAD ...continued Figure 8 (leŌ): the DXF Mesh Export OpƟons (General) window. Figure 9 (right): the DXF Mesh Export OpƟons (Export Bounds) window. Once your mesh is done exporƟng, open it in AutoCAD Map 3D. When it first opens, you will only see black or a grey grid. Click on the “3D” buƩon to view the mesh properly in 3D, as seen in Figure 10. Figure 10 (leŌ): The 3D mesh surface shown in AutoCAD Map 3D Click on the “3D” buƩon to iniƟate this view. Page 4 Global Mapper Contours can be generated easily in Global Mapper by clicking on File, then Generate Contours...This will open the Contour GeneraƟon OpƟons window, as shown in Figure 11. The main thing you have to fill out is the Contour Interval; however, you can cus‐ tomize some of the other opƟons as you see fit. The smaller the contour intervals, the longer it will take to generate. Similarly, if you click on the SimplificaƟon tab, you will see a slider (Figure 12). To the leŌ creates smoother contours (i.e. less angular), but takes a bit more Ɵme. To select the area you wish to generate the contours for, click on the Contour Bounds tab and select the Draw a Box buƩon. Press OK once you are done to start the contour generaƟon. Generating Contours Figure 11: the Contour OpƟons window Figure 12: the SimplificaƟon tab Figure 13: the newly created contours. To export theses contours as vectors in SHP or DWG formats, select from the menu File then Export Vector Format… www.library.carleton.ca/find/gis Page # Global Mapper Loading a DEM into Global Mapper This help guide will show you how to: Page # Global Mapper Viewing the DEM in 3D Exporting a DEM to a 3D .DXF Mesh for AutoCAD Page 3 Global Mapper Exporting a DEM to a 3D .DXF Mesh for AutoCAD ...continued Page 4 Global Mapper Generating Contours
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