Latest Contributions by NeilAyres

Jostein, Note the operator "touches". It just touches the line. There is no area overlap to intersect. You could add a tiny extra distance to "distance" (what are your geometry coordinates?), then there will be an overlap. Cheers, Neil ... View more

Meg, what's the coordinate system of your dem? Please post the coord sys tab & extents tab of the properties page here. Thanks, Neil ... View more

Robert, wouldn't you do this with the "Make Feature Layer" tool from the toolbox. There you can add a sql expression. Will do the same thing as a definition in the properties. Only the selected data is passed on to the next process. You can probably copy your selection text from the dialog you do manually in ArcMap. Cheers, Neil ... View more

Sarah, I am surprised you are not getting some errors with this code. As far as I am aware the area & length of a geometry object are properties of the object. I can find no reference to a .getArea() function. So why not try... area = geomObject.area length = geomObject.length Or just recover the area and length using the tokens for this purpose (SHAPE@AREA, SHAPE@LENGTH : less expensive on resources than manipulating the full geometry object. Cheers, Neil ... View more

Or you could look at Ianko's tools : http://www.ian-ko.com/ The ET surface module can animate cross section of a surface going down a route (a stream line for example). Cheers, Neil ... View more

Jamie, if you have elevation data in the form of contour lines and spot heights, the first thing to do is to make a DEM from this. Perhaps TopoGrid in spatial analyst, or the tin building tools in 3d analyst. Note that the OS topo 50 data might not be detailed enough to give you a realistic representation to accurately visualise 50cm changes. Once you have a tin surface in ArcScene, create a large polygon underneath your data, then use the base elevation setting to set the polygon at the desired height. If you want to get volume differences (between this level plane and the tin), the polygon has to have an "elevation" attribute so you can use the Polygon Volume tool. Good luck, Neil ... View more

Justin, use circles instead... But seriously though. My rotated symbols (these arrows are pointing in the direction given by an attribute) - pic 1. Are rotated by the correct amount when I apply a df rotation as well - pic 2. ArcGIS 10.1 SP1. Cheers, Neil ... View more

This thread seems to be going off track..... Have you had a look at : http://resources.arcgis.com/en/help/main/10.1/#/Walk/018w00000023000000/ And use arcpy.Describe functionality as detailed above. When I want to point to a specific location to run a script I normally just set a variable like import arcpy, os from arcpy import env HomeDir = "c:/Data/Path to dataset.." db = "MyData.gdb" InputData = os.path.join(HomeDir, db) env.workspace = InputData Cheers, N ... View more

Derek, looking at that list of coordinates, it appears to be Lat / Long. ie the first column is +30 odd deg , and the second column is -85 odd deg. So when adding XY table, specify the X, Y the other way round and define the projection as GCS_WGS84 (plain geographic cords, not Web Aux). Having a quick look at my world map, these points are somewhere in Florida. Good luck, Neil ... View more

I have also found Mark Pilgrim's Dive into Python really useful for all the basics... List manipulation, dictionaries and much else. http://www.diveintopython.net/ Cheers, N ... View more

If you're using a TIN to model the data, these are really designed to handle a contiguous block. Gaps are always interpolated across them. Try using a raster representation instead, there you can use masks to make the no data areas really NoData. N ... View more

A snippet from Mark Pilgrim's "Dive into Python", chapter 7 about the re module.. "Regular expressions are extremely powerful, but they are not the correct solution for every problem. You should learn enough about them to know when they are appropriate, when they will solve your problems, and when they will cause more problems than they solve. Some people, when confronted with a problem, think "I know, I'll use regular expressions." Now they have two problems. �??�??Jamie Zawinski, in comp.emacs.xemacs (http://groups.google.com/groups?selm=33F0C496.370D7C45%40netscape.com)" All the stuff about parsing phone numbers etc is in there. But re expressions just give me a headache...! But well done for the answer. ... View more

Rikus, once you have a tin, slope, aspect and elevation are all part of its properties. Go to the symbology tab and add the slope, then display this. Or am I misunderstanding your query? Neil ... View more

Lake boundary polygons (lines of constant elevation) and stream lines and other sorts of topo data can be all input into the topo to raster function. Just read the help "How Topo to Raster works". It is the best tool around for this sort of data. ... View more