Simply Statistics

Blog recommendation: simplystatistics.tumblr.com

DPI and pixels per inch (PPI)

As a general rule, PPI = 2*DPI

I wanted to create a photoshop document that I will later use in a poster presentation. Generally, poster images should be done at 150 dpi, so I created my photoshop doc at 300 pixels per inch.

On focused dataframes in ArcMap

Q: Why can't I add a north arrow/legend/scale bar to my map?

A: Are you in the layout view (vs. the data view, often the default view)?

Q: Yes, of course. I didn't just install the software this year, you know.

A: OK, I can see I'm dealing with a non-novice here. Let's try something else. Is your layer focused?

Q: Um... it's clear to me, so I guess it's in focus?

A: No, I mean that if you're looking at the data view, is there a diagonal line border around it?

Q: Yes...

A: OK, that means you have that layer focused. It allows you to edit the layer in the layout view. See this thread for more info. To un-focus the layer, hit this button on your toolbar:

For me, it's located a few lines below the word "Selection", but as always the location of the buttons depends on where you have your toolbars anchored.

Word count in MS PowerPoint 2007

I'm a big fan of sparsely worded scientific posters, and I've challenged myself to keep my next one to under 300 words. I will be doing my final poster project on Adobe InDesign, but I'm putting together a draft on PowerPoint, and I found this thread that explains how to word count in PowerPoint:

Click the office button, hover over "Prepare", click "Properties". On the left side directly above your workspace, there will be a dropdown for "Document Properties". Use this and select "Advanced Properties", and choose the "Statistics" tab.

Not as easy as Word, but at least it does the trick.

Hat-tip Frank Robledano on this thread

Can ArcMap calculate area?

Yes, yes it can!

First create a field, then right click your new field and select "calculate geometry". ArcMap will calculate the area based on the projected geography (or another geography if you chose).

Is your layer not projected? Check this post out.

Adding coordinate data to a shapefile and lining up your layers

...or, Why is Maryland floating out in the Atlantic Ocean?

If you find that one (or more) of your layers aren't lining up in your mxd file, it's probably a problem with the geographic and/or projection coordinate systems. Your layers need to be projected in the same system. You can check the projections by right clicking the layer in the table of contents, selecting "properties", and looking at the information listed for both Projected Coordinate System and (by scrolling down) Geographic Coordinate System.

If you need to re-project a layer, see this post (steps 1 - 3) on how to. Remember to add your newly projected layer to your mxd file, and remove your "floating in the ocean" layer.

A problem arises if you have a shapefile that lacks coordinate data. You just can't re-project something that hasn't been projected yet.

For example, the 2000 census zip code shapefiles (available here) lack a coordinate system. When you download the zip file, it does not include the projection (.prj) file for the shapefile. Adding this layer will result in the zip code layer floating in the ocean.

To add a coordinate system, open Arc Catalog (not just the shortcut thru ArcMap). Select the shapefile that corresponds to the layer that is missing the coordinate data by double clicking it in the table of contents so you get a popup window. In this window, go to the XY Coordinate System tab, and click "select" to select a pre-defined coordinate system. Chose the appropriate coordinate system, click "add", and then "ok".

Re-add the layer to your mxd file. Check the properties to make sure the coordinate system has been updated. If the layer is still out of line with the other layers on your map, go through the re-projection steps described above.

Source: ArcGIS Desktop Help

Another R tutorial

http://pages.pomona.edu/~jsh04747/courses/R.pdf

Metadata in ArcGIS10

The metadata file is embedded in the shapefile and can be accessed through ArcCatalog.

Open ArcCatalog 10 (not the shortcut through ArcMap10). Find your shapefile of interest in the table of contents on the left side of the screen. Click on the shapefile to open it. The main window on the right has 3 tabs, "Contents", "Preview", and "Description". Click on the "Description" tab (it may take a minute to load). Scroll down to the bottom of the screen to see if "ArcGIS Metadata" and "FGDC Metadata" is available. If they are, click on these titles to open the metadata. If they are not, or if you are looking for a particular style of metadata, you can change the metadata style by clicking on "Customize" on the very top of the page. Choose "Arc Catalog Options" and open the "Metadata" tab. You can choose the metadata style from the dropdown menu options here.

Calculating age in Excel

If you have an event date and a date of birth, Excel will calculate the age-at-event for you through this formula:

=INT((A1-B1)/365.25)

Where A1 is the cell with the event date, and B1 is the cell with the birthdate.

Shortcut courtesy of http://excel-formulas.blogspot.com/2005/08/calculate-age-in-excel.html

Uploading files to ftp

This morning, an email requested that I upload sensitive files to a lab ftp. The email gave me the site, user name, and password, and nothing else.

If you ever find yourself in this position, may I suggest starting here:

http://filezilla-project.org/

Download the Client -- it's all you'll need to do a simple file transfer.

Next, hit this up:

http://wiki.filezilla-project.org/Using

The quick guide is both quick and easy to understand.

One big headache I have not been able to overcome is the size limitations on transferred files. I'm trying to upload multiple shapefiles with over 3K records and 20+ fields... anyone out there have a workaround short of breaking up the shapefiles in ArcGIS???