GIS Tips & Tricks

A weblog dedictated to the lifelong pursuit of cartographic bliss in GIS.

Wednesday, October 26, 2005

Add Date, Time & File Name Stamp to an ArcMAP Layout

I have never figured out why there is no INSERT DATE option in ArcMAP. Maybe it's just me but normally I put a DATE on my layouts. Isn't it a cartographic standard?

Fortunately there are a many ArcScripts out there that allow you to add a DATE STAMP to your layout and they usually include a FILE NAME option as well.

The organization I'm currently GISing for has admin rights really locked down so registration of .DLLs for Tool Controls is difficult. Luckily I was able to find a Date Stamp script at the ESRIs ArcScripts site that's creates a button control that allows you to add a text box for Date, Time, & File Name on your map. It's opensource code too which means it's easy to customize for your own enjoyment. Use this link to download the zip file to your PC and follow the instructions in the txt file.

Once installed you'll have a date stamp icon on one of your toolbars.

When added to your map the fully manipulable textbox will look something like this:

Wednesday, October 26, 2005 11:24:00 AM

Kudos to Jonathan Garner for creating this script.

Monday, October 24, 2005

Georeferencing an image in ArcMAP

Scenario: Someone gives you a hardcopy map with a couple of polygons hand drawn on it. They want it in the GIS so you can make a pretty map for them and run some analysis. What do you?

In my opinion, you bascially have three options:
1. Use a digitizing tablet;
2. Eye-ball it off the map – often called ‘heads-up digitizing’ or ‘on-screen digitizing’; or
3. Scan the map, georeference the image and trace the polygons.

I’m going to quickly run throught the third option. For fun let’s call this geotracing. If you don’t have a digitizer it’s probably the best option…besides I’ve never been a fan of the on-screen digimonkey thing.

So as I mentioned above you’ll need to scan the map. Hopefully there aren’t too many maps and the polygons are concentrated in smaller areas that fit nicely on your scanner. I would recommend scanning to JPEG or TIF either will do fine.

Okay now that you have your images saved let’s fire up ArcMAP and launch the GEOREFERENCING toobar. Right click on the main toolbar and select Georeferencing.

Add some topographic layers to your ArcMAP document. Depending on your map, normally roads, water features and contours will work well.

Add the image you want to georeference. Don’t worry about ArcMAP complaining about the image missing a spatial reference information.

Using the Zoom tools roughly navigate to the area where the polygon should be added.
On the Georeferencing toolbar select> Fit to Display

As a personal preference, I also like to have Auto Adjust selected.

Your image should now be visible behind your layer features.

Select the Add Control Points button.

Begin adding control points linking features on your image to the GIS layers. As you add more control points the image will begin to morph and shift to the correct location.

If you added an unlucky control point that you wish to remove you can deleted in the Link Table. Beside the Add Control Points button select the View Link Table button. Select the link you wish to remove and hit the delete button.

Once your are satisifed with how your image lines up to your spatial data, you may wish to save the rectified image. Georeferencing> Rectify… > Save. The rectified image will be saved as a TIF.

Now that the source image is rectified it’s simply a matter of tracing or ‘geotracing’ the polygon(s) of interest. To do this I create an empty polygon shapefile. ArcCatalog> Right Click> New> Shapefile> Name it and select feature type> Polygon. If you know the spatial reference information it would be a good idea to EDIT that information here as well.

Now that you’ve created an empty polygon shapefile, add it to ArcMAP, Start Editing on the EDITOR toolbar and ‘Create a new feature’ by geotracing the polygon on your georeferenced/rectified image. Save Edits, stop editing, et Voila! You probably want to add fields and attribute information to the new polygon(s) but you already know how to do that…don’t you?

Custom Legend Patch Shape

Want to make your own custom legend patches in ARCMAP to match polygon or linear features? Here’s how…


From the Customize menu select the COMMANDS tab. Select the Page Layout Category and choose the New Legend Patch Shape. Drag the tool to your favourite toolbar.

Click the New Legend Patch Shape button. The New Legend Patch menu will appear. Select Area or Line. Select the layer to use in Patch Shape and whether the features to create the patch will be all, visible or the selected features. Click Create Patch> Click Add to Styleset and specify a name for the new patch. Click OK.

Now that you’ve created your new patch it will available for you to use via the Legend Wizard patch selector. Enjoy!

ArcMAP Symbols

Here's a great link to ESRI's ArcMAP symbols in their vast styles catalogue.

Suggestion: Download the PDFs, print them out and decorate your cubicle!

Multi-Lined Legend Labels in ArcMAP

PROBLEM: legend label too long to fit in legend area without reducing font size.

SOLUTION: use the label DESCRIPTION option instead where multi-line label descriptions are possible. See below>

Select Edit Description…
The Description for Legend input box will appear. Enter the label description here. For a new line use CTRL-ENTER. Select OK.

Right click on the legend and bring up the legend properties

Select the ITEMS tab. Right click on the layer in Legend Items: and select Properties…

The Legend Item Properties box will appear>

Unselect the checkbox for Show Labels and select the check box for Show Descriptions. Click the Description Symbol… button.

Description text is by default italicized. Unselect the and select OK.

Here's the RESULT: