Node Dangles

I admit, I love picking up freebie maps. Whether it is from the front desk of a hotel or from the bicycle shop, there is a certain appeal to seeing what people put on maps. I have maps organic orchards, breweries, Minnesota authors, rails to trails, zoos, fictional places, race maps, and a variety of other things that someone felt the need to cartographize.(http://thefriends.org/wp-content/uploads/2012/12/mn_writers_on_the_map_web_download.pdf)http://thefriends.org/ So, with all these paper maps lying around, I was thrilled to find Custom Maps, a free app on Google Play.

Obviously Cartographers belong in the same category as other superheroes like Superman, Batman, and Spiderman and we finally have a our own comic book to prove it. Cartozia Tales is a collaborative effort of nine indy artists with two guest artist each issue. They have an interesting plan, they’ve split the world into nine regions (what’s the name for the ninth of an area, nona-rant?) and the artist will tell a story from a different region each issue.

When I first found out about GIS, the first application that came to mind was using it to map my running routes. At that time, I was using paper maps and scraps of paper to measure how far I was running each day. GIS obviously offered a better method. Almost twenty years later, GPS has become so common place that I think we have four or five devices in our household that have GPS capabilities and measuring my runs has become ridiculously simple.

I was recently re-evaluating our back-up procedures and discovered and found a nasty bug with the arcpy’s ListFeatureClasses request. If you have a feature class in a feature dataset with the same name, ListFeatureClasses may not find it or anything else in that feature dataset. Unfortunately, we recently made our daily backup a python-based system that uses ListFeatureClasses and got bit by this bug. After discovering missing data in our backups, I reconstructed what happened and found this bug.

I had a user with a series of GPS points (that were in chronological order) that they wanted to know the accumulated distance from the start to each point in their shapefile. First, we calculated the distance from each point to the previous point into a field called [DistFt]. Then, we hacked out this quick python function to accumulate the total distance in Arcmap’s Field Calculator: totalDistance = 0 def accumulateDistance(inDist): global totalDistance totalDistance += inDist return totalDistance And we called it:

Recently we took a call from a user who could not see the legend for one of the feature classes in one of our services. (Precambrian Bedrock in http://mgsweb2.mngs.umn.edu/arcgis/services/state/mnbdrkgeology ) After trying some standard things–restarting the service, checking the source .MXD–I turned to The Google Machine and quickly found help from ESRI: http://support.esri.com/zh-cn/knowledgebase/techarticles/detail/33741 . Turns out the default number of legend items ArcMap will display from an ArcGIS Server map service layer is 100 and we had 102 in the problematic layer.

I was helping a co-worker who needed to check if a field exists in their arcpy script. Since we were located at their computer, I thought I would just do a quick Google search and pull the code off this blog. Seemed logical since I the original purpose was exactly that—to serve as a handy, public place to store code snippets that I use & that others might find handy.

In the last week, I have looked for multi-part features a couple of times. Today, I was looking for multi-part polygons after dealing with the fall-out of a case of Clip Gone Wild as shown below. I have not found a way to write a query to find these but Field Calculator does allow you to calculate a field’s value to the number of parts. Using the Python parser, just write the formula (note that case matters): !

One of my main tasks right now is to document many of the details of maintaining ArcSDE geodatabases so I anticipate having several blog posts on this topic that are re-writes of documents I am working on. I am presuming that the person will have no ArcSDE experience so I am documenting very detailed information. Almost all of the ArcSDE commands require that you specify which instance (service/port) the command applies to by using the ‘-i’ parameter.

Ok, it has been to long since I last posted and I thank those few people who asked If I had suffered a Segmentation Violation or something. By means of a brief explanation, I changed jobs last summer, going back to a previous employer in a very different role than what I’ve ever had before. It was a challenging and difficult and one that I had minimal success at but, in the end, didn’t work out.