Topographic cross sections, or profile graphs, benefit anyone interested in elevation changes.
A topographic map depicts a portion of the landscape and is widely used to plan routes for transportation, pipelines, or simply hiking. Although a topographic map has many benefits, some users also need a profile of the topography in the form of a topographic cross section showing elevation changes from the map. ESRI's ArcMap 9.3 software creates a cross section, or profile graph, in ESRI's ArcView terminology, by using topographic data. (see References 1) The completed profile graph shows topography vertically along a horizontal line on the map.
Instructions
1. Open the ArcMap 9.3 program obtained at a license level for ArcView or above. On the "File" drop-down menu, select and open an existing project file that contains topographic data.
2. Create a triangulated irregular network (TIN) to use as a necessary three-dimensional data set from which to create a profile graph. With the project file open, select the "data layer" on the left that contains topographic data. Using the 3D Analyst toolbar, select "Create/modify TIN" and select "TIN from features" to open a dialogue box. On the left of the dialogue box, place a check next to the "data-layer name" used to create the TIN in this step. On the right of the dialogue box, use the "height-source" drop-down menu to select the name of the column that contains topographic data in the "attribute table" of the same "data layer." In the dialogue box, accept the default name and location of the new TIN data set. (see References 2)
3. The profile graph function displays elevation changes along a line.
Select the "interpolate-line" button on the 3D Analyst toolbar to create the line for the cross section on the map. Click at the beginning and double-click end of the desired profile line on the map display. A dotted box with handles encompasses the line, which shows that the line for the cross section is selected.
4. Click the "profile-graph" button on the 3D Analyst toolbar while the line is selected. The new profile graph opens as a separate window to show a wiggly line of the topographic cross section.
Tags: cross section, profile graph, topographic data, Analyst toolbar, contains topographic, contains topographic data, elevation changes
