Generating contours with ArcGIS

Making land surveying with a total station, apart from having pinpoint accuracy, it also may be useful for other purposes, given that you have the elevation of each point. In this case, let’s see how generate contour, which was already sawn with AutoDesk Civil 3D, Bentley Geopak and Manifold GIS, so for educational purposes, in this case we will do it with ArcGIS.

1.  CAD Data

For this exercise, I have the uprising files in dgn, one for each day of work. Importing it is as simple as:

• Arctoolbox
• Data interoperability
• Quick import

The dgn files are selected, and voila, everyone is inside. See how nice they look when themed; you can see days when guys worked, when they strove and when they work as Birdbrain (Spanish Idiom: “guevonearon”, loose their time instead of working).

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More than interesting, you may notice where points were taken, in this case almost alone in the bearing changes of blocks; to make the foreground and background they used tape. It is practical to support the lifting method by the time when appears no matches with documentary measures or other uprisings. You may also note where the equipment set up to make the view back.

2. Entry points to the geodatabase

For better handling, I’ll enter the points to a geodatabase. To do this, we assume that this is already created with ArcCatalog and it is defined a Feature class.

• ArcToolbox
• Conversion tools
• To geodatabase
• Feature class to geodatabase

3. Create a digital model

Several of these steps can be overlaided, but for purposing of understanding the use of 3D Analyst, we will see it in this order.

• ArcToolbox
• 3D Analyst tools
• Terrain
• Create terrain

UIT this we have only defined model’s name, lets enter the points:

• Add feature class to terrain
• Build terrain

Now, we’re going to generate the TIN

• ArcTool box
• 3D Analyst tools
• TIN creation
• Create TIN

You can see that at the extremes there are not enough points, so triangulation remains poor; but it kept consistent where the streets are.

Also I noticed that by their innocence, in this uprising, guys failed for not maintaining the lift in a change of the equipment. This is a salvageable error and it can be repaired by interpolation from nearby points, but the observation may have time to make the corrective. It may also be suggested that in the first two points of the geo-referenced, they should use elevation coordinate provided by the GPS and sufficient distance to reduce the rotation error generated by the inaccuracy of GPS.

4. Generating the contours

Always in 3D Analyst

• TIN Surface
• TIN Contour

Here we choose the TIN just created, the target layer and spacing between the contour lines (among other pirouettes I save me for space reasons).

The steps are more when compared to Manifold GIS, but the options are much more powerful.

5. Generating the slope map.

• TIN surface
• TIN Slope

What comes is to use this, you can either apply it for a sewage systems design, because this not only is an uprising plot, but a topographic uprising with which you can work with streets profiles with just a couple of steps.