Archive | October, 2010

Geocode to Rooms in a Building

24 Oct

Continuing with the theme of GIS inside the building, in this post I will show how to geocode students to classrooms inside of a building.

First, import a CAD file to use as a base.  Once the file is in and located properly, draw the classrooms in GIS as a polygon shapefile.

The classrooms need a field that can be used as an address. Create a new field and insert the room number of each room. If you want to code more than one building at a time, then room number would not work — there cannot be duplicate addresses. In that case you would need to create unique addresses for each room — the school acronym followed by room number may be a good start.

For this example I have created a student list. Each student is named ‘Student’ plus a number and is assigned to a classroom. The list is shown below.

Create an address locator in GIS using a single field. Pick your reference data and the key field and click OK. Geocode the address list using the newly created locator. Add points to the map. Your file will look like the one below.

There is only one point in each room. If you use the INFO tool and click on a point you will see a list of all the students at this location.  To create a better visualization of our data we will count the number of points in each room.  In the point shapefile create a field called COUNT and set the value equal to 1.  Join the room shapefile with the point file based on location. The output will be a single colored room file that looks like this:

Looking at the properties of the file you will see the COUNT field summed for the number of students in each room.

The last steps are to change the SYMBOLOGY of the shapefile based on quantity, using COUNT as the field. Add a label and you will now have a color coded shapefile showing the number of students in each room.


Down Save Revit Models

23 Oct

I hate that Revit will not allow me to open a 2011 model in 2010. When upgrading to 2011, my office decided to only move certain projects over and leave others. We took in to account the fact that we could not down save and once we were in 2011 we were stuck in 2011.

There is a workaround! If you really need to open a model from a later version of Revit you can — by using IFC.

WARNING: You will lose information. Your walls, windows, doors, and some other elements will be safe, but the model will not be 100% complete — depending on how detailed it is.

To see what will export, go to EXPORT>OPTIONS>IFC OPTIONS

As you can see, Area Tags will not export by default. If you are familiar with the IFC tags you can export objects that are currently not exporting by specifying what tag should be used in the IFC.

Export your model to IFC. Voila! you now have a text file (.IFC) that should look as follows.

From an earlier version of Revit click R>OPEN>IFC and select the file. Now you have a 2011 model in 2010 or 2009. This is also a good way to get your file to many other programs.

DISCLAIMER: I do not recommend using this as a way to work on a daily basis. This tip is for those times when it is absolutely necessary to go between two different version of Revit. You should talk with all parties involved in a project and decide on a version before beginning your project.

Fire Escape Plans

20 Oct

In my last post, I mentioned that the Network Analyst toolbox in GIS could be used to create fire escape plans for buildings. In this post I will build on the last model and show how to create a fire escape plan.

The model consists of a CAD drawing with hallways drawn and converted to a network.

To find the nearest exit from any location in the building I will use the Closest Facilities tools. First, I need to create a point file marking the location of all the fire exits. Added to the model, we get:

Next, the exits point file is imported in to the closest facility tool and we place locations on each point in the building we want to find the correct exit for — shortest walk. The black squares are the locations we will solve for.

Finally, solve the problem. The results will be drawn on the map as shown below.

GIS Inside the Building

17 Oct

At schools of Architecture across the country, GIS courses tend to be filled with Planners and Landscape Architects — and maybe that one adventurous Architect fulfilling an elective. Can you blame those Architect? GIS courses are structured to examine the neighborhood, the city, the county, the state, or in a class full of Landscape students, a site. Why would an Architect sit through such a course? What does GIS have to offer him?


In this post I will show how GIS can be used inside of a building by modeling a hallway as a network data set, and then find the shortest path between any two points within the building.

The first step to creating the network data set is to import the building floor plan from AutoCAD to GIS. The following is the result.

Next, the editor toolbar in GIS is used to sketch the hallways connecting the spaces in the building. For this example I have kept the model as a single story. The hallways could be drawn in 3D joining the first and second floors of the building. In the image below, the purple lines are the hallway paths.

The hallways are a new shapefile which is then converted in to a network data set in GIS. Using the Network Analyst tools, I pick two points — the first on the left of the building and the second on the far right.

The last step is to tell GIS to find the best way to get from point 1 to 2. GIS is capable of solving based on several variables – the two most common being cost (time) and distance (shortest). In this example, I solved the problem based on the shortest path. The result is below.

In this example, the shortest path involves going outside of the building.

The Network Analyst toolbox allows us to examine an existing or proposed building design. These tools should be used to model the best fire escape routes. They can also be used by safety personnel during emergencies.

GIS should be seen as a series of tools for spatial analysis- both outside and inside of buildings.