Latest Contributions by CamillaRootes

‎12-29-2016

I have been sent some data that I need to project in Arc 10.4.1. The data is in two formats: .GRID and .AGR. The .GRID files are a DEM and the .AGR are ice thickness measurements. When I 'add data' in Arc or access the folders through the Arc catalogue, I can't see either of these file formats. Can anyone advise me on how to display these files in Arc? What software can I use to convert them into a usable format? Thanks

‎10-27-2016

near_delta is set to True I've done a computation of the z value in the table and it worked fine. Both are in the same coordinate system

‎10-27-2016

I am using the Near 3D tool in Arc 10.4.1 (basic licence) to compare two point shapefiles, both of which have z values. I am interested in the nearest delta x, y and z values between the two sets of points. When I run the tool, I get correct outputs for delta x and delta y but the delta z column returns only values of 0. The z coordinates for the nearest point is also shown as 0, despite the every point in the shapefile having a z value. Can anyone suggest why I am not getting the correct delta z values and advise me on how to fix this issue, please?

‎06-02-2016

I have Et Geowizards 11.3 installed for Arc 10.1 and have added the ET Geowizards toolbox to the ArcToolbox. However, when I try to run an ET Geowizard tool I get the error message 'Tool not licensed'. This also happens when I try to run ET Geowizard tool via the Model Builder. The tools run fine from the ET Geowizards dialog box. Can anyone explain why they tools won't work in the ArcToolbox or Model Builder? NB - what I really want to be able to do is to batch process using ET Geowizard tools. If I can get the tools to work in the ArcToolbox or Model Builder then I will be able to do this, but I can only run the tools for a single layer at a time in the ET Geowizards dialog box. Thanks, Camilla

‎04-09-2016

Thanks for suggesting this. I'd not thought to put the code block in syntax format but it definitely improves the document.

‎03-17-2016

I've written up the solution to this problem, including Field Calculator Python codes for straight line length, percentage slope and degrees slope. See this document for my write-up: Python code for straight line slope of a polyline (inc. straight line length, pecentage slope, and degrees slope)

‎03-17-2016

Follow these instructions to calculate the percentage and degrees slope for any polyline layer with z values. 1. Add fields to the attribute table for: a) straight line length; b) percentage slope; c) degrees slope. 2. Use the Field Calculator to compute the straight line length using this Python code. NB - if your polylines are straight, then you can omit this step and instead calculate the Length field using 'Calculate Geometry' as normal. Code block: import math def GetDistance(shape): distance = math.sqrt((math.pow(shape.firstpoint.x - shape.lastpoint.x, 2)) + (math.pow(shape.firstpoint.y - shape.lastpoint.y, 2))) return distance 3. Use the Field Calculator to compute the percentage slope using this Python code. NB - if you have straight polylines then you can subsitute the normal 'Length' field for the straight line length (called Straight_L in this example). Code block: import math def GetSlopePerc(shape, leng): ratio = (math.fabs(shape.lastpoint.z - shape.firstpoint.z))/ leng percentage = ratio * 100 return percentage 4. Use the Field Calculator to compute the percentage slope using this Python code. Note that Slope_pcen is the percentage slope field. Code block: import math def GetSlopeDeg(shape, percentage): ratio = percentage / 100 radians = math.atan(ratio) degrees = radians * (180/math.pi) return degrees Alternatively, you can return the slope in degrees using this maths module function: math.degrees() (Thanks to Neil Ayres for suggesting this alteration) Hopefully this has been helpful! Let me know if these codes through any errors for you.

‎03-17-2016

I've got it working. Unfortunately my university is tight and will only supply me with Arc 10.1, which doesn't have the Add Geometry Attributes tool. So I used the old fashioned 'Calculate geometry' function to add start and end z values to the attribute table. However, this was returning a z value of 0 for both the start and end points of every polyline. After a bit of snooping I discovered that the z values for the layer had somehow reset to 0. Presumably during some other processing I'd done previously. So I re-extracted correct z values from a DEM of my study area. This got 'calculate geometry' to return the right z values and meant that my slope codes worked perfectly. Here is the final code for percentage slope (using straight line length between the start and end points): And here is the code I used to get slope in degrees from the percentage: Thanks for all your help!

‎03-15-2016

I've resolved the NameError and the code is now executing. I have also computed the straight line length of the polylines sucessfully and substituted this field into the code in plac of SLength. This is my current code: At the moment this is only returning a value of 0. Working through the calculation for a couple of the polylines suggests that I should be getting values other than 0. Do you have any idea why I am only getting 0 values out of this code?

‎03-15-2016

Hi again. I've only just had the chance to test these changes but the code is still returning an error. Here is my current code: This is the error that it is returning: Thanks for your other point about the straight line slope. On thinking about it I do think that I will need to use the straight line slope. So I will add another field to compute the straight line distance between the first and last points and will substitute this field for SLength.

‎03-09-2016

Just noticed the error on line 4 in the above code. Have corrected it, but it wasn't the cause of the issue.

‎03-09-2016

I've made changes to the expression box and the indentation. What do you mean about passing the SLength field in? At the moment I'm still getting the same error, with the syntax issue still on line 3. Here is the code:

‎03-09-2016

Hi I am trying to calculate the % slope of multiple polylines in a shapefile. I am using Arc 10.1 with the basic licence. When I run my code in the Field Calculator I get a Python syntax error on line 3. I can't see the issue - can someone tell me where I'm going wrong? My code is: NB - I am not sure what directions the polylines were digitised in. Hence I don't know if the last point is at the higher elevation or vice versa, which is why I am trying to return the absolute change in z value. The error read out I am getting when I run the code is: Thanks in advance!

‎06-23-2015

Hi I'm currently trying to make a map doc using 202 raster DEMs, but I'm finding that Arc keeps crashing. At present I am just using the rasters as normal individual layers and am wondering if this is just too much data for my system to handle. Can anyone suggest a better way of bringing together this many rasters? The DEMs are the outputs from an ice sheet model and each raster represents the ice cover at a given point during the modelled time period. They are all of the same area and I need to overlay them in the same map doc, so that I can click through and see the changes. I will also need to do some basic processing to get polygon outlines of the ice cover for each raster and to use the Raster Calculator to sum multiple rasters. I am using Arc 10.1 with a basic licence. Thanks!

‎11-27-2014

The answers to your questions are: yes I have looked at them; they all have a length that looks correct; the start and end points don't match; they have different orientations (but none should produce azimuths of 0); they're definitely not multipart polylines. What I've done is to re-download the data and ran the whole process again from the start. This appears to have solved the issue - I'm now getting correct azimuths for every line. Putting it down to a corrupt download for now, I'll keep working on it and get right back on here if the issue reappears! Thanks again

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Date Last Visited	‎11-11-2020 02:23 AM

My Ideas

Latest Contributions by CamillaRootes

Displaying GRID and AGR files in ArcGIS

Re: Near 3D tool not outputing z results

Near 3D tool not outputing z results

How do I get ET Geowizards to work from ArcToolbox?

Re: Python code for straight line slope of a polyline (inc. straight line length, pecentage slope, and degrees slope)

Re: Slope of polyline - Python syntax error 000989

Python code for straight line slope of a polyline (inc. straight line length, pecentage slope, and degrees slope)

Re: Slope of polyline - Python syntax error 000989

Re: Slope of polyline - Python syntax error 000989

Re: Slope of polyline - Python syntax error 000989

Re: Slope of polyline - Python syntax error 000989

Re: Slope of polyline - Python syntax error 000989

Slope of polyline - Python syntax error 000989

Managing large numbers of rasters

Re: WARNING 000405 when using 'Calculate field'

Re: Slope of polyline - Python syntax error 000989