arcgis

Most Frequently Used Coordinate System

Most Frequently Used Coordinate System

In the ArcCatalog, drag and drop your most frequently used coordinate systems into the top level of the Coordinate Systems folder to put a copy of them into that location for quick access to them on dialog boxes.

o   In ArcCatalog, choose Customize ► ArcCatalog Options… from the main menu bar.  In the General tab and check the box next to Coordinate Systems.

o   Expand the Coordinate Systems folder to where your desired coordinate systems are and then drag them up to the main Coordinate Systems folder.

Large Menu & Toolbar Buttons

For those of you who have a hard time seeing the small tool buttons (commands) on your toolbars, it is possible to make them larger.

o   Choose Customize ►Customize Mode…from the main menu bar.

o   Choose the Options tab and check the box next to Large icons.

Regular Menu & Toolbar Buttons:

Large Menu & Toolbar Buttons:

Customize ArcMap 10 Toolbars

Creating custom toolbars is one of the easiest ways to tailor ArcGIS desktop applications to the way you work. In addition to positioning toolbars in a specific area of the application, you can group commands on a custom toolbar.  Save mouse clicks by creating a new toolbar that contains frequently used menu choices, new macros, or custom commands from another source.

o  Choose Customize ►Customize Mode… from the main menu bar.

o   To turn toolbars on/off simply check/uncheck the box next to the toolbar in the Toolbars tab.

o   Shortcut:  right-click on the standard toolbar (just below the main menu bar) and the select the toolbar(s) you would like to be visible. 

o   Toolbars can be docked anywhere or float in the application.

o   While the Customize dialog box is open, the tool buttons on visible toolbars can be rearranged and new tool buttons (aka commands) can be added from the Commands tab, just drag and drop the tool button to the visible target toolbar.

Adding X,Y Centroids to Polygons in ArcGIS ArcView

Creating a centroid point file from a polygon in ArcEditor or ArcInfo is quick and painless.  In ArcToolBox go to Data Management Tools/Features/Feature to Point and follow instructions.

There is a downside to this convenience however.  8,910 dollars of them in fact, the cost of an ArcInfo license.

How to calculate centroids in ArcView.

  1. In the attribute table of your polygon layer and under Options choose Add Field.
    Add Field

     

  2. Add an X and Y field of type Double
    Add Field Dialog
  3. Right-click on the New X Column Header and choose Field Calculator.

     
  4. In the Field Calculator Dialog that opens, click Help

    Here's all the instructions you need, but they are written in ESRI.  Allow me to translate.  Copy this section:
      Dim Output As Double
      Dim pArea As IArea
      Set pArea = [Shape]
      Output = pArea.Centroid.X

    Paste it into Field Calculator.  Check Advanced, and enter Output into the final textbox.

    Like this:
    Field Calculator

     

  5. Click OK and repeat for Y.

You now have the X,Y coordinates of the polygon centroids.  If you really need a separate point layer, copy the DBF file for your polygon layer to a new file and add as a point layer using the Add X,Y Data... dialog under the Tools menu.

Resource to check your maps and webpages for the color-blind

Are you a red means "Stop" and green mean "Go" kind of person?  You might want to rethink this approach for cartography.

Here's an example of just how poorly your maps may translate for the color-blind.

So before pressing print, save an image and run it through some software to see how it translates to those with Deuteronopia, Protanopia and Tritanopia:

  • Vischeck lets you upload images to their server to view with various kinds of colorblindness.
  • Color Oracle installs on Windows, Mac and Linux for local processing on large files.

Don't forget the real world too... ask around and find coworkers who can evaluate your maps before publishing.

 

About geographic transformations and how to choose the right one

I just stumbled on this most helpful post About geographic transformations and how to choose the right one by Aileen Buckley of ESRI's Mapping Center.  I even learned a few things from the comments...

I'd highly recommend the read, but if you only have a moment, read this:

So how do you choose the geographic transformation that should be used? Here are two Esri Knowledge Base articles that can help you:

HowTo: Select the correct geographic (datum) transformation when projecting between datums. This article contains links to downloadable zip files (for different versions of the software) that contain a list of all available datum transformations and their appropriate geographic areas of use.

HowTo: Determine which NAD_1983_To_WGS_1984 transformation to use.  The gist of this article is summarized below:

  1. NAD_1983_To_WGS_1984_1 - for the entire North American continent.
  2. NAD_1983_To_WGS_1984_2 - for the Aleutian islands.
  3. NAD_1983_To_WGS_1984_3 - for Hawai'i.
  4. NAD_1983_To_WGS_1984_4 - superseded by _5; this transformation method should no longer be used!
  5. NAD_1983_To_WGS_1984_5 - for the 48 contiguous United States.
  6. NAD_1983_To_WGS_1984_6 - for the Canadian province of Quebec.
  7. NAD_1983_To_WGS_1984_7 - for the Canadian province of Saskatchewan.
  8. NAD_1983_To_WGS_1984_8 - for the Canadian province of Alberta.

Note that geographic transformations work in either direction. For example, the transformation listed as NAD_1983_To_WGS_1984_5 transforms from NAD 1983 to WGS 1984, as well as from WGS 1984 to NAD 1983. When using the Project Tool, the geographic transformation is recorded in the metadata.

GIS Q&A for Professionals

The best programming question and answer site on the web now has a dedicated GIS section.

http://gis.stackexchange.com

This is a great resource to try next time you have a question that you know others have faced.  You can limit your results to just gis.stackexchange.com performing a google search by adding the parameters "site:gis.stackexchange.com" to your query.

Here's a demonstration

 

ESRI Mapping Center has some Style

Take a minute to check out the ESRI Mapping Centers' ArcGIS Styles page and you will see that we have included graphics of the contents of the styles you can download. The center is easy to browse and you can download any style or symbolset to use in ArcGIS.  Ofcourse, some of the symbols will be a little hard to see in their full glory in these screen captures (for example, marker symbols that are bigger than the space allotted in the ArcMap Style Manager large thumbnail view.) However, you can still get a good idea of the contents.

Here's a couple examples to whet your appetite:

Gradients for Different BiomesElevation color ramps for different biomes. download ShadeMax

SubtleSet of light shades of a variety of hues. download Subtle Artist Light Colors

Color Deficient Set of colors for maps for the color deficient. download Color Deficient

View all the styles, plus models, scripts, expressions and more at the ESRI Mapping Center ArcGIS Resources Gateway

Also, just adverNPS Symbolstised, and to be added soon to the MapCenter Resource Page are National Park Service (NPS) symbol sets.

You can download these today from the NPS Harpers Ferry Center.

It is available there for download in a multitude of formats:

Map Symbols

Map<br /><br />
symbols
Recreation pictographs, north arrows, bar scales, road shields, etc.

Other Symbols

Other<br /><br />
symbols
Pictographs for accessibility, winter recreation, water recreation, etc.

NPS symbols are free and in the public domain. They derive from Ultimate Symbol Collection, a commercial product that offers hundreds of additional symbols.

TrueType Font Symbols

Map<br /><br />
symbolsOther<br /><br />
symbols
Fonts include both the Map Symbols and Other Symbols shown above.

ArcGIS Symbols

Map<br /><br />
symbolsOther<br /><br />
symbols
Includes both the Map Symbols and Other Symbols shown above.

Map Patterns

Map<br /><br />
patterns
Lava/reef, sand, swamp, and tree patterns (accessed as a swatch library in Adobe Illustrator CS or later).

There's lots of great options out there!  Try a new style today!

Repairing Broken Data Sources

What do you do when you open your map and you have a layer that looks like this? What does it mean?

The red exclamation point is a visual indicator that something is incorrect in the layer's data source.  To fix it you'll need to know where the data lives and tell the layer in the map this information.  You're giving direction to poor lost layer so it can find itself, you're a metaphysical geographer!

 Repairing a data source:

  1. Right-click on the layer, from the contextual menu choose Properties
  2. In the Properties dialog box choose the Source tab
  3. Click Set Data Source
  4. Browse to the location of the data layer, select and click Add
  5. OK out of the Properties dialog

If all went well your data is now displayed.

But what if it isn't one layer?  What if you have an entire map of mis-pathed layers?

Here's where ArcCatalog comes to the rescue:

  1. Locate the map in ArcCatalog
  2. Right-click and select Set Data Source(s)
  3. Highlight one of the Data Layers that is in error and click Replace...
  4. The find box should load with the erroneous path of the layer you select, if not enter it
  5. In the replace box enter the correct path and click Ok
  6. Repeat as necessary

But what if they are SDE Layers?  This whole batch thing is no help at all.
Yes, this is where it gets nasty. Basically, you're left out in the cold.  You can either fix them one at time, or you're going to need a little script my coworker developed and that isn't so simple.

An Inquiry Into IN Query

I had to select a ton of records today for a project in ArcGIS. You know the normal method, hellish SQL repetition: ID = 1 OR ID = 5 OR ID = 6 OR ID = 12 OR ID = 14 OR ID = 27 OR ID = 41 OR ID = 43


The past few months I've been working a lot in SQL Server and this experience made this repetition seem like too much work. So I got lazy and I made an inquiry into IN query: ID IN (1,5,6,12,14,27,41,43)


And it just worked. There's no documentation in the main help file that even mentions it. If you do open the ArcGIS Help and search on "SQL Reference" nearly half way down you find a section on Subqueries. Here they explain that IN queries are supported in geodatabases and EXISTS is supported as well! Who knew? How was I supposed to know this if I hadn't gotten lazy?

Here's what you'll find in the ArcGIS Help File:

Subqueries
NOTE: Coverages, shapefiles, and other non-geodatabase file-based data sources do not support subqueries. Subqueries done on a versioned ArcSDE feature class which has been registered without the option to move edits to base will not return features stored in the delta tables. File geodatabases provide the limited support for subqueries explained in this section, while personal and ArcSDE geodatabases provide full support. For information on the full set of subquery capabilities of personal and ArcSDE geodatabases, refer to your DBMS documentation.

A subquery is a query nested within another query. It can be used to apply predicate or aggregate functions or to compare data with values stored in another table. This can be done with the IN or ANY keywords. For example, this query would select only the countries that are not also listed in the table indep_countries:

"COUNTRY_NAME" NOT IN (SELECT "COUNTRY_NAME" FROM indep_countries)

This query would return the features with a GDP2006 greater than the GDP2005 of any of the features contained in countries:

"GDP2006" > (SELECT MAX("GDP2005") FROM countries)

For each record in the table, a subquery may need to parse all the data in its target table. It may be extremely slow to execute on a large dataset.

Subquery support in file geodatabases is limited to the following:

IN predicate. For example:

"COUNTRY_NAME" NOT IN (SELECT "COUNTRY_NAME" FROM indep_countries)

Scalar subqueries with comparison operators. A scalar subquery returns a single value. For example:

"GDP2006" > (SELECT MAX("GDP2005") FROM countries)

For file geodatabases, the set functions AVG, COUNT, MIN, MAX, and SUM can only be used within scalar subqueries.

EXISTS predicate. For example:

EXISTS (SELECT * FROM indep_countries WHERE "COUNTRY_NAME" = 'Mexico')

OperatorDescription
[NOT] EXISTSReturns TRUE if the subquery returns at least one record; otherwise, it returns FALSE. For example, this expression returns TRUE if the OBJECTID field contains a value of 50:

EXISTS (SELECT * FROM parcels WHERE "OBJECTID" = 50)

EXISTS is supported in file, personal, and ArcSDE geodatabases only.
 
[NOT] INSelects a record if it has one of several strings or values in a field. When preceded by NOT, it selects a record if it doesn't have one of several strings or values in a field. For example, this expression searches for four different state names:

"STATE_NAME" IN ('Alabama', 'Alaska', 'California', 'Florida')

For file, personal, and ArcSDE geodatabases, this operator can also be applied to a subquery:

"STATE_NAME" IN (SELECT "STATE_NAME" FROM states WHERE "POP" > 5000000)



Remix IN with some external SQL that EXISTS here in ArcGIS One-to-Many Labeling and you might confuse ArcSDE for an RDMS. Just don't try look for anything meaningful in a RELATE.