rjhale

Python and Iterating in ArcGIS

May 4, 2012 by rjhale

So yesterday’s post got quite a few views. Someone asked “…but you said you could do this in python”. Since I couldn’t sleep last night I did it in Python.

I’ve had this long running discussion in my head “So What are you good at…” . I can easily list the things I’m not: electrical, plumbing, carpentry, and programming. I like programming. It’s fun. When I started using ArcInfo oh-so-many-years ago you had to know AML or you were going to not have a lot of fun. I hated Visual Basic just enough to not go in that direction when this version of Arc we all know and love came out. I learned perl. Then started this long running infatuation with Python. I use it just enough to be dangerous.

In yesterday’s example you had a watershed you needed to separate. We did it in Model Builder. Today – Python. Instead of an iterator we declare a Search Cursor. I won’t go into all the ins and outs of python formatting or why you type pythong at times when you mean python. I will encourage you to read the ArcGIS help. There are a lot of good examples of how to use python to make your life easier. Python is more than just an ArcGIS tool. You can learn it and then step into ArcGIS and still be lost (or at least I am) trying to learn all the functions and ways to do things. There is no doubt a better way to do what I am going to show you.

You need to separate out the watersheds. Open up a python window….and start typing. I assume at some point you’ve been curious enough to dump a model into python. My phrase of “start typing” is misleading – you have to know what to type. Location of the Python icon is below.

It takes me a while usually to get “in the mood” and I start off making mistakes. Lots of mistakes. The thing you need to do is declare a search cursor. Locate the Field and loop through the results. It’s half art. The nice thing about the python window is you can load files into it and save information out of it. It will also prompt you along through the help window. Eventually I got tired of making mistakes.

I saved what I was doing into a text editor and made changes and load these back into a window. Expressions are a pain. There are too many quotes and double quotes and what not to make it fun. I always forget. I always have to go back and think and look at examples. Eventually – success! Here is what I ended up with (documented for your enjoyment)

import arcpy #declare a cursor rows = arcpy.SearchCursor(fc) #Loop through the cursor for row in rows: #Grab the Field huc = row.HUC_10 #Build an expression Pre = '\"HUC_10\" = ' #Format the variable to get it in Quotes Post = "'%s'" % huc #build the expression expression = Pre + Post arcpy.Select_analysis(fc, "C:\\temp\\watershed_" + huc + ".shp", expression)

So what did we learn here? You can do this in Python if you’re not scared to type. You can save it and re-run it (like model builder) and it’s another tool to get you an answer. It took me a bit longer because I had forgotten about formatting the variables to get quotes and SQL all straightened out. I have no doubt there is a better way to do this. Also – if you know your Arc Python lingo – it takes about the same amount of time as model builder – maybe less. Since I forget some things it took me a bit longer.

Know your data and your tools. Have some fun.

Of Fish and GIS

April 17, 2012 by rjhale

No one in my family knows what I do. It’s become a bit of a running personal joke. Most days I’m the guy that’s good with “computers”.

Every now and then something funny happens. Nothing out of the ordinary – it just makes me laugh. I installed gmail on a neighbor’s computer. This morning I was pulling python code out of my ass to fix something that wasn’t quite working right….and Dad called. My Dad discovered email not that long ago. The one man who hates computers and most everything technological has now figured out – or at least he did over a year and a half ago – email. I could bore you with the back story but he has a cousin in Miami. So they trade pictures over email. I know what you’re thinking – those kind of pictures. Pictures of dogs. Weather. Kids. Family. Boats. Fish. Alligators. A digital camera and email has made all the difference. His world which has mostly been confined to a very small area got a bit larger. “Come look at what Jerry sent over the email”.

Today’s problem involved fish. Dad went fishing and wanted to share picture of Poxmosis nigromaculatus – plain old Crappie (pronounced Cropee).

Somehow Picasa and Email had become disjointed. “It’s broke and won’t send my pictures” was the technical explanation. I fixed it. It took some hand holding and a bit of just click this (My dad – a very successful 8th grade dropout doesn’t read exceptionally well) and we sent pictures across the wires and through the void. Mom asked if I had fixed it and I said “Yup – Dad Won’t have any problems from here on out with email”. I snuck and sent one copy to myself. He worries about me since he has no clue in general what I do and how I even support myself. “My son makes maps” and I smile and wave and leave it at that. He has yet to fly on a plane. I don’t think he’s seen the Mississippi River.

I have a lot of things I want to accomplish. Next on the list is go fishing.

Introduction to Quantum GIS Class now being offered

April 10, 2012 by rjhale

The last few weeks have been interesting. I’ve been making a lot of decisions about different things. One of the things I’ve been wrestling with is training. I’m an ESRI CTP. I’ve worked hard to get that designation. It’s an integral part of this company. With that program more or less ending I’ve been offering everyone breaks on training to just just train. It really made me think though what happens when it ends.What do you do when your business partner tanks 1/3 of your business plan……..

I got the chance a few years back to teach URISA’s Open Source GIS Workshop. Actually I did one better than that – I co-taught it with the person that wrote the book. No pressure there. I have taught it twice and both times I’ve learned a bit more. Both times I’ve incorporated things I learned back into my work environment.

When one door closes another opens. I’ve got a lot of thoughts rolling around in my head on why I’m doing what I’m doing. I can’t quite let them out yet – but I can start letting some out.

I’m announcing my first custom class – Introduction to Quantum GIS. It’s a 1 day class and I’m starting out offering it at $275 dollars – it may go up or down. It’s not quite done – I’m still working with the slides and am filling out class exercises. I’m taking a slightly different approach with the class – I’m targeting GIS Professionals and trying to show them how well this software works and how it can be used. I use it not quite every day but I’m starting to get close. I’m turning into one of those guys who will work with about any software to get the most important thing right – the data.

Things we will cover in the class:

Map Layouts
Symbology
Editing Vector Data
Vector and Raster Data
Plugins
Labeling

I’m excited. I’ve had the luck of speaking with a developer on the project. More widespread exposure helps the software develop. Plus, anything that makes me a better GIS person and pushes me more is a good thing. With that said this isn’t the last class I’m going to build – I’ve got an idea for a couple of more and depending on how this class goes there might be more Quantum Classes. Who knows. Watch for a OpenStreetMap class coming this summer.

Email or Call with questions. I’ll answer what I can.

Small Business Year in Review: Volunteering

December 21, 2011 by rjhale

So this one is going to be interesting. I was going to do a twitter one but decided to jump over just a bit into some forbidden territory.

So one of the things I like…nay…love..maybe that was too strong a word…Greatly in Like with…is GIS. This year has been a bit of a re-awakening of that fling. When you start a business as I did with a handicap (no one knew who I was 5 years ago – like anyone knows who I am now – HA) you do all sorts of crazy things. One of those was tracking down a group(s) and just asking them if I could make maps. It’s led to some interesting moments this year. Volunteer work is my canary in the mine-shaft so to speak. If I hate my volunteer jobs it’s time to move beyond what I am doing. Some of the best work I have done has been volunteer oriented and not just from a standpoint of non-profit organizations. If the work has some sort of merit I don’t care about your status. I will work for lunch. I don’t use it as a tax writeoff. Actually now that I think about it I’ve never written any volunteer project off for tax purposes. I just do them. Maybe I should.

So it led to several weird and wild things this year: Working with a High School (again), working with GISCorp,and working with who(m)ever…. I was busy this year and it showed. Things that typically weren’t a problem doing became a problem. I had a hard time communicating to clients and my volunteer jobs. I learned a lot this year on how to approach people and what I was capable of because of the volunteer work. The canaries started squealing….or squeaking…or chirping….

Caribbean Sea: The big push for this group this year was to get their website…eh – weblife moved into their hands. They had a domain they didn’t own. A website they couldn’t fix. Email that was blinking off randomly. If you go to the website it’s now wordpress (and as you can tell they have been working on it), the email is now a gmail backend, and things more or less work. At least they own the domain now – that was 120 days of ICANN rules and craziness as we went from Mambo to WordPress. It wasn’t as smooth as I wanted….but it transitioned. Their email was down longer than it needed to be…the transition was not as smooth as I wanted….but at least they are in more control for better or worse.

Red Bank High School: My most problematic volunteer effort this year. Right in the middle of the biggest job I had landed as a business they popped up. ESRI donated an ArcGIS lab for the school. We ended up using it on a NASA Project. Something I thought would take a week at most took a month as I built models to compile data and churned out numbers as the kids/teacher estimated ages of craters on the moon. It taught me to be a bit more realistic as to planning and more truthful with the teacher. It was stressful. It showed. I enjoyed working with the kids Typically we do OSM. That’s easy. ArcGIS added unforeseen complications. I learned. their final project for this year centered around water quality. They digitized buildings and concrete. They took water samples. They related water quality to development in the watershed. For the finale they tested the schools water fountains and found ecoli. That was worth the effort to watch the principal sit with her mouth hanging open at the work, the effort, and the fact that all water fountains near the bathrooms weren’t clean enough.

GISCorp: I like GISCorp. If you’re a GIS person and slightly “bored” you have no excuse – volunteer. I was working on one project this spring and like I said above my life was getting tight. So I had to drop out of the project. I hated it. It annoyed me to no end. Luckily as things settled down I got involved again this winter. I am leading a small team of people digitizing in OpenStreetMap for HOT.

So when I started this company my fist thought was “I’m nuts”. The second thought “it’s not all about the money”. It is…it isn’t. I can’t throw large amounts of cash at a problem. I have no Randy Hale Foundation….but I do have North River Geographic Systems, Inc. I can do some things I want to do.

How long will I keep volunteering? It could be said if the company fails…if this whole thing becomes un-doable….. I might find something else to do…. A plan B if you will….but I can keep volunteering as a GIS Person and at least keep my foot in the industry.

Small Business Year in Review: The Facebook

December 18, 2011 by rjhale

Sorry – it’s been a few days. I’ve been balancing my books (I’m also the book keeper – that will probably change this year also).

The hardest thing to do when you are a small consulting business is advertise. Especially if you’re NRGS and you don’t necessarily focus on one thing. I do a little bit of everything and I really need to focus on one industry. It’s a symptom of up upbringing in the GIS Community – I did a lot of things at my former job. I joked I was a McGyver of sorts at things….or as I have been told Jack-of-all-Trades and Master of none.

Advertising has always been a head-scratcher for me. I’ve joined organizations and different things all for the chance to get my name/link on a website and spread the word. The worst organization I joined was the BBB. They have a place – but it’s not in my line of work. I’ve sent out newsletters, I’ve sponsored groups, and I’ve taken out ads in magazines. I’ve done about everything I can think of to spread the word. One thing I did this last year I guess (maybe I did it in 2010) was to make my business a page on Facebook. My thought was I could blog/tweet (more on twitter next go around) and I would push it to my Facebook business page. So I spent a few minutes and did just that – set up my blog to push out through Networkedblogs. Granted – this all is a “free service”. I could pay for ads on Facebook (or Google for that matter) and start targeting consumers. What I have noticed over the last year is no one is coming from Facebook back to my business. It seems (to Me) I’m spending a lot of time worrying about it…it’s not paying off. Maybe if I actually paid for the service it would be different but the whole reason I’m talking about it is that I’m a small business. Money is tight.If I saw something from it I might pay for the service.

Facebook is a time killer. It’s killed a lot of my time. It’s great for keeping up with people. It’s great for me as a venting tool (I post some seriously silly things on my page). I think for a brick and mortar store it probably works. For people selling things online that have a targeted consumer demographic it probably works. For a guy who makes maps and and answers crazy questions about data it doesn’t work or at least it’s not working for me. In most cases Facebook is blocked at businesses and by the time a person gets home no one is going to “OMG – there is a GIS consulting company on Facebook I must call them”.

So this upcoming year I’m going to worry less about Facebook and how I am interacting with it. I’m going to give Google+ more of a go. I will still feed my blog out to Facebook – because as a small business any advertising is good advertising. What I have some to learn is that there are different levels of good advertising and for me Facebook isn’t one currently.