March 25, 2008

GIS and CAD Signs, Symbols and Fonts

While driving to Oklahoma for the National Christian Homeschool basketball championships this month, I and three other parents rotated driving duties for the 21hr non-stop trip along much of Route 66 (I-40) from California. I pulled shifts in the overnight hours getting to watch the sunrise over the steering wheel, and one shift included a morning snow storm near Flagstaff on the way home. My daughter snapped the accompanying picture in the middle of the night at one of our driver rotation stops somewhere in No-Where New Mexico. Looks like the sign has seen a hard life and was even reused from some signage in days gone by.

At the tournament our girls were one of the youngest teams in the 18yr old and under division and won 3 of their 5 tournament games to finish 21st. Finishing up one spot higher than their initial ranking with a loss to the Indiana state champions and a good team from Missouri that fielded a talented All-American player. We met coaches, parents and young people from all around the country. We had a nice time talking with one team from Wisconsin earlier in the week that we ended playing in our last game. We even sat with them at the awards ceremony. We asked the Wisconsin girls if they had enjoyed meeting other girls from around the country, their point guard gave us a troubled and confused look and responded, 'Girls!?... we’re meeting BOYS!'

One of the primary point symbol types supported by ArcMap is the use of true type-fonts as marker symbols. I use true-type marker symbols in both ArcGIS and CAD when I want the symbols to be the same in both the CAD and GIS versions of converted data. Although I have more flexibility in the creation of cells and blocks for CAD symbology, the ability to reference existing ArcGIS marker symbols in a true-type font can be easier than recreating a CAD symbol set of the GIS marker symbols for interoperability. The trick to getting the ESRI marker symbols in CAD is to create CAD text rather than points. The ArcGIS Export to CAD tool available with an ArcView license, allows me to export point features as CAD text by overriding the default [CADType] with TEXT and then specifying the Unicode character or formatting code string in the text value stored in the [TxtValue] field of the point feature layer’s table.

I can specify the right symbol with CAD formatting syntax in the text string recognized by CAD (ie: [\U+0073], or use the keyboard short cut to type in the actual Unicode value in the string once I’ve done a little research to find the values of the symbols I want to use. Finally to get the right symbol in CAD I need to have access to the same true type font in ArcGIS as in the CAD system. Export to CAD will then use the true-type font referenced by the [TxtFont] field that I include in the feature layer attribute table or an existing CAD font style based on that true-type font that I could reference in a field called [TxtStyle].

Luckily we don’t have to travel for the final games of the year. Wish us luck as we play this week for the California State Tournament Championship.

11 Comments:

Anonymous zihad said...

hi Kuehne

I am trying to export my .mxd or Layout file [into AutoCAD 2008 file (.dwg, .dxf)and cant get anything to show up. It this even possible?

1:32 PM  
Blogger Don Kuehne said...

Great question. The answer is, no you can't really do that. You can Export the contents of your layout, but if I understand your question you want the Layout and layer symbology, north arrow etc...? The geoprocessing tool Export to CAD will export features to CAD entities, but not Labels, graphics or layer symbology. I take it exporting the layout would have value to you.

Question: Would a Map Service accessed via ArcGIS for AutoCAD do the trick, or do you need the entities?

2:58 PM  
Anonymous Anonymous said...

Don:

I hope they are paying you a mint at ESRI; you are a wealth of knowledge. I work for a medium size city government. We are contemplating setting up a requirement for new developments to give us asset and attribute data about infrastructure they are building. We will use it in our GIS for many purposes; one being GASB 34 reporting. Do you know of any other City or County requiring this and if they have any standards already in place? I have talked to a couple that require a few assets but not much attributes about those assets. We would like for example, a stop sign asset with attributes like the size, wood or steel pole, height, hardware, etc.

Allen

2:11 PM  
Blogger Don Kuehne said...

Thank you for your kind words. I am not personally familiar with the GASB 34 reporting requirments. You might find some useful help here ...

http://gislounge.com/gasb34-and-gis/

10:15 AM  
Anonymous Anonymous said...

I would like to export line and area symbologies to CAD (an area filled with circles to a CAD where every circle is one element).

Is this possible?

Thanx for answer

1:57 AM  
Blogger Don Kuehne said...

ArcGIS will export features from ArcGIS to CAD. It will use the different possible geometries of GIS features, Points, Lines, Annotation, and Polygons and express them as CAD entities. If you have many circle features in the GIS then you would have no problems exporting those to CAD. However, what I suspect you are asking is to export a polygon pattern to CAD. Or generate a CAD polygon pattern in CAD. In the CAD of exporting the GIS polygon symbol pattern, that is not currently possible. Polygon and Line symbology are like paint and do not contain actionable or accessible geometry for which CAD features can ge generated. The other option would be to use CAD patterns. These are knwon as hatches. Currently ArcGIS does not export hatches either. The best bet is to use the relatively simple post processing workflow of using the Hatch commands in AutoCAD, or Automating that post process with a CAD API that looks for certain features in a drawing that you've exported and then replacing those features with hatches of a certain pattern or adding the hatches to those geometries.
Back on the GIS side there may be some way to generate points within the polygons that you could then export as locations for the center's of circles for which you could create AutoCAD blocks that you could then EXPOLODE in CAD to get individual circles. That is a more complicated workflow and depending on what you are really trying to do there may be several other otpions that might work.

9:16 AM  
Anonymous Wes K said...

Don are there any good true type fonts out there with standard cad symbols? I've gone through the ESRI symbols and have not found the symbols I'm looking for. It is a fire hydrant symbol with with three isosceles trianlges pointing into a circle (I wish I could send a picture).

9:58 AM  
Blogger Don Kuehne said...

Wes,

If you have ArcGIS installed there are lots of TrueType fonts that are the ArcGIS marker symbols. Besides those I don't know of any special source. One trick might be to use the basic symbols on top of one another to build up a symbol from its elements: a triangle on top of a circle, etc...

10:23 AM  
Anonymous Anonymous said...

Don,

I am not too sure on the year of these posts, but what is you perspective on the changes and improvements in converting ArcGIS symbology to AutoCAD? I have ArcGIS 10 and am aware that "seed files" or DWG templates can be used to append exported GIS data to existing block groups in CAD. More specifically, can this seed file and block group creation be applied to all types of geometry such as points, lines, and polygons or is it just points? The reason I ask is because the ArcGIS online help only refers to points for this seed file preparation. Thanks!

1:04 PM  
Anonymous Peter said...

Hi Don! I have a problem. I'm student od geology, and i'm drawing a geologic map in ArcGis for my final exam, but I don't have all patterns and line types on ESRI library. I downloaded a CAD files with them (from my colleague), but I don't know how to add it and use in ArcGis. Is it possible, and if it's not, what i'm gonna do?
Thank you!

1:43 AM  
Blogger Don Kuehne said...

ArcGIS and CAD have different methods of assigning symbology. ArcGIS has a custom CAD renderer that does handle the basic CAD line styles and colors. However there is really no way to access the renderer if the data is not in a CAD file. By that I mean there is no way to mimic or use the CAD symbology on non-CAD GIS feature class. That said you can select the individual CAD symbols we have created that ship with ArcMap to get the different named line styles. These are the ESRI-CAD symbols. However there is no magic method of understanding your CAD block or cells as GIS point symbols. ArcGIS uses generally true-type fonts to define vector symbols and CAD users any vector combinations you want to put together. The ESRI-CAD symbols only have the basic CAD line types and not an exhaustive list, nor any custom line styles that you have in any CAD drawing. Hope that helps...

10:18 AM  

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