Geometric Networks and Arc C++ SDK

Geometric Networks

Dr. Lee has an interesting paper about the 3D data model for representing relationships of urban features, it can be found here: http://gis.esri.com/library/userconf/proc01/professional/papers/pap565/p565.htm

Another interesting paper about Transportation networks in ArcGIS can be found here: http://gis.esri.com/library/userconf/proc02/pap0437/p0437.htm

It seems that ArcGIS has the functionality to create topologically related geometric networks, but only on the 2D scale. There are also network analysis tools integrated into ArcGIS that can provide such functions as "find path" that will allow us to minimize the amount of code that we have to write to get our system working.

Implementation can be done either by creating a new geometric network or making one from an existing file. For our application, it will probably be done by starting from scratch.

Here is a screen shot detailing the functionality of the Analyst:




ArcGIS SDK

I have installed the SDK on the computer I have been using in the VIS lab, it has an Object Browser, GUID generator, and library search tools. This should prove useful when interfacing with C++ or any other programming language.

ArcGIS SDK, ESRI dev network, and database files

ArcGIS Desktop SDK for Visual C++

I just acquired a copy of a education version of ArcGIS 9 from the Geography department, and it has the C++ SDK on it. I haven't yet had a chance to play around with it, but it should prove to be very useful for the project.

I have also signed up to the ESRI developer network, which has a code exchange, scripts, and other useful information. This service will no doubt prove useful in the future. The weblink is: http://edn.esri.com/

I have also located a useful article that explains in detail how to compile and run applications written in C++ using the SDK, that link is located here: http://edn.esri.com/index.cfm?fa=codeExch.howToCSamples

Progress on Shapefile annotations, database files, and georeferencing...

The shapefile format actually consists of 3 files, one of which is a dBase file that can be read by MS Access. This file will be used to link the spatial info to the right attributes. Currently, the dBase file is quite cluttered since the CAD files were so detailed (there are point features for individual seats in rooms), the next step would be to clear all of the unwanted information out, and expand of the information that is needed. Many of the features need to be discarded for our purposes, and once this is done it should be easier to work with the files.

I have made some advancements on georeferencing the CAD files to it's appropriate place in an orthophoto. By choosing control points on a georeferenced map, you can link them to other control points you have defined on a CAD file, shapefile, or image. They are then transformed to the new coordinate systems and line up with the control points. The initial test of this didn't seem to work well, as I was not able to get the CAD file to "drape" over the appropriate area. It did indicate that it was matching the coordinates I had defined earlier, however. My goal here is to eventually have a model that displays the CAD or shapefile draped directly over where it's supposed to be in the orthophoto. I could later use this referencing to create a 3D model of the build environment.


Editing Geometric Networks...

This is a tool that is used to represent connectivity in utilities systems, and may have some use for our purposes. By defining connectivity rules, you can go through and create a geometric network that represent connectivity relationships spatially. There is a possibility that we can use this in conjunction with a route finding algorithm to visually display routes in ArcGIS.

Info on Shapefile and progress on conversion and developing a working model.....

Progress

Today I finished converting the .dwg files over to .shp files for our use. I have successfully created shapefiles for all floors of Woodward Hall and the other building (I think it's CRI). I have discovered a way to create all shapefiles from the .dwg documents in ArcGIS. I have all of these files stored on my H: drive currently, and hope to have them stored somewhere else shortly.

Before I was only able to convert the polyline and polygon features, but no I have the ability to create shapefiles that represent annotation, multipatch, and point features.

Next Steps...

The logical next step would be to start annotating features that are in the shapefiles that I created. This will involve specifying room numbers, identifying which wall are outside/inside, and determining hallways and other information.

Shapefiles

I have been reading into information about the shapefile format and stumbled across a helpful pdf file put together by ESRI:


http://shapelib.maptools.org/dl/shapefile.pdf

It contains some useful information about the format of shapefiles and specific information about what is in header files, record contents, and how features (polygons, lines, areas) are represented in the file. This will be useful if interacting with the shapefile using a programming language.

Shapefile C Library

Jianfei pointed this site out to me earlier this week. After further examination it seems to be a great source for a shapefile API. The link is: http://shapelib.maptools.org/

Final Thoughts...

It will soon be a necessity to have a central location for storing the files I have been creating. My H: drive is simply too small to contain all of the shapefiles that we are going to need for our models.

I have also contacted Paul Smith about concerns I have about the project and other GIS questions. I have asked that he come to one of the meetings on Friday to discuss information he might have that will be helpful in our project.