Monday, November 10, 2008

Open Question: How to query shapes in GE?

I know there are plenty of sophisticated ways to bring your GIS
shapefiles into Google Earth but I am kind a wondering if there is a
way to open attribute tables and do some basic queries within GE.
There is some sort of a solution to it using Mapwindow GIS and GE
opened at the same time, but still, what about a person that is sent a
.kml file and want to take look at a specific value within say
hundreds of records?

Wednesday, October 8, 2008

Ripping information from ArcIMS databases - Legally, of course

So, you're surfing the web, you find an ArcIMS database that has all kinds of neat GIS data that you would just love to get your hands on. They offer it for free online, but you have to use there IMS server. Now, I love ArcIMS as much as the next guy, but sometimes it is frustratingly slow. And not to mention poorly designed. Also, most of the time, you just want to manipulate the data for yourself!

1) you should contact the database administrator and kindly ask him if you can have access to the data for your own copy of ArcMap

2) You could manually digitize the data (ugh), by finding and using a series of control points on the map ie. landmarks that you are familiar with

3) Get it by some other means. I would never condone stealing from an ArcIMS database, but I would like to know if there is a way to do it.

I want to compile a guide that helps with this! So, please contact me with the comment section if you have any information that could lead to my getting ArcIMS info.

Friday, February 22, 2008

ArcGIS Annoyance: Arc Map Crashes or Hangs when Plotting or Printing to PDF or a printer

ArcMAP will repeatedly crash when you try to print your map sometimes, usually when you are dealing with a large amount of on-screen data (in terms of both space it occupies on the hard drive as well as how complex the polygons are). If you are attempting to print or PDF a file that has, let's say a huge raster background and a very complex polygon layer draped over it, often ArcMAP will hang or crash. It may or may not give a memory message.

The reason for this is usually memory related. ArcMap manages memory poorly by comparison to some other software. Generally, as a rule of thumb, when you have a document open and it takes a long time to draw the layers when you pan, you might have this issue when you try to print your MXD.

The solution: Since it is usually memory related, there are a number of memory related fixes you can try to get ArcGIS to print or plot your document.

1) Try restarting your PC and immediately, once it has booted, go into the ArcMAP document and try to print/ export to PDF. This may work because on a fresh boot your RAM is clear, for the most part. Any actions you do after a fresh reboot slows your computer because the clean space in your RAM never fully recovers. More RAM will give the PC more space to create a PDF or make a file to be sent to the printer.

2) Reduce the output resolution DPI. Do this only if the quality level is acceptable, if you need the quality to be ultra high try one of the other solutions. Lower print qualities, especially for rasters, can really diminish the appearance of your mapping output.

3) Increase your pagefile size. If your document is failing to print for memory reasons, there may be no other solution than making your windows page file size larger so ArcMAP can handle the memory load. You can set page file size (maximum) in your control panel. This may fix this annoying ArcGIS 9.2/9.x issue.

Tuesday, February 19, 2008

AutoCAD Annoyance: Can't Select Some Text - SOLUTION!

AutoCAD 2008 (as well as 2007 to the best of my knowledge) features an annoying bug where you can select some of the Mtext on the page, but not others. There does not seem to be a rhyme or reason as to which text you can or can't select. It generally occurs in paper space, but I have had it happen in model space. You just can't select some of the words you have written. I have no solution to this issue, but I do have a work-around.

When you can't select some of the things you have written as mtext in autoCAD, simply type the command QSAVE (which is short for quick save). This saves you document and, inexplicably, enables you to select all text again. If this doesn't work for some reason, save your DWG document, close AutoCAD and re-open your DWG. This is a surefire way to 'fix' this bug.

Using Masks in AutoCAD to cover underlying features (hiding transparency)

In most programs, hiding underlying features is easy, but, in AutoCAD’s polygon/polyline based interface it is less easy. This article will outline three methods for whiteing out backgrounds in AutoCAD.

1) Text Masking: If you want text to have a black background (ie. White), enter the mtext properties, select “background mask” and click to select a mask that matches your background color (which may or may not be white). You can also use this command to select a colour of your choice to mask the text. Background masking can also work for other types of features and will be discussed at length in a future article.

2) The ‘wipeout’ command: this works well for an areal feature, like a polygon that surrounds text ie. Text in a box. Type the command wipeout, hit p for polyline, select the box surrounding your text in AutoCAD, then choose not to erase the box (obviously). What this will do is cover all of the features behind the feature you have selected. One draw back to this command, I find, is that when you re-open the document later, a bug often shifts the layer ordering, messing up what you have done. Silly AutoCAD!

3) Finally, when all else fails, a simple hatch can cure your AutoCAD woes. Select the polyline you wish to hide the interior of, type hatch (or h for short), choose solid color, then select the colour that matches your background by default.

Well, these three somewhat annoying to use commands are the only way, that I know of, to grey out background items in AutoCAD 2008. You should now be able to do away with transparencies in all of your CAD .dwg files. Hopefully.