New tool - Count Coincident Lines

I have a new ArcGIS geoprocessing tool out called  Count Coincident Lines on ArcGIS Online or by clicking HERE.

Sometimes we want to know the number of coincident line features in a feature class. For example, perhaps we are interested in the movement of organisms on a landscape and we have multiple least-cost path lines that we are interested in depicting using varying line widths or colors.

 

 

 

 

 

Figure 1: Lines are overlapping so it isn’t possible to depict which segments are coincident with others.

 

 

 

 

 

Figure 2: Line widths depict the number of coincident lines.

Parameters

The tool has only four parameters and does not create any intermediate files.

Input Lines  - The input lines parameter should have multiple coincident line features and should have a projected coordinate system.

Coordinate system – This is the native coordinate system of the input lines. (Right click on the layer – Properties – Source - Projected Coordinate System).

Length unit – The native length unit of the input lines (Right click on the layer – Properties – Source – Linear Unit).

Output Lines – Output line shapefile or geodatabase feature class.

 

 

 

 

 

Figure 3: Dialog for the Count Coincident Lines tool.

Model

The model consists of four simple steps and uses tools that only require a Basic ArcGIS license. The first step uses the Add Geometry Attributes tool to add the START_X, START_Y, MID_X, MID_Y, END_X, END_Y. These are reserved fields and should not be present in the input lines.

Next, the model adds a field called COUNT (also a reserved field)  and calculates count such that each line segment has a values of 1.

Finally, the tool dissolves based on the START_X, START_Y, MID_X, MID_Y, END_X, END_Y assuming that lines with these six values in common are coincident.  There may be circumstances where this assumption is violated so please think carefully about whether this is true for your data or not.

The number coincident segments per line is shown in the COUNT_COUNT field (also reserved) and can be depicted on a map like in Figure 2.

 

 

Figure 4: Count Coincident Lines tool as viewed from Model Builder (right click - edit).

Citation

Dilts, T.E. (2020) Count Coincident Lines Toolbox for ArcGIS. University of Nevada Reno. Available at: https://www.arcgis.com/home/item.html?id=6b0d7669d7ea4cc3b62ecddea209c251

ArcGIS Idea - Extract Multivalues to Polygons

ArcGIS would be much more friendly if it had a tool called "Extract Multivalues to Polygons" that saved users some joining steps.  See my idea - HERE

Paul Burow's work featured on the Mountain West News Bureau and NPR

Congratulations Paul Burow on having your research featured on NPR! This is really interesting stuff.  You can view the NPR news story at this link:

https://www.kunr.org/post/rural-westerners-may-be-changing-their-minds-about-government

The project website is at this link:

http://covidruralwest.org/ 

Paul is a PhD Candidate at Yale University in the School of the Environment and Department of Anthropology, but he lives in Reno, and participates in lab meetings of the Great Basin Landscape Ecology Lab. We are very lucky to have him, as he is always very thoughtful, broadens our discussions, and brings a new perspective to the discussions.  Thank you Paul.

Work featured in National Geographic article

I'm excited to see that our article in the journal Water titled "Rapidly Accelerating Deforestation in Cambodia’s Mekong River Basin: A Comparative Analysis of Spatial Patterns and Drivers" is getting some press.  It was recently featured in the National Geographic article by Stefan Lovgren "Cambodia’s biggest lake is running dry, taking forests and fish with it". In fact, the main figures are derived from our data!  Deforestation in Cambodia is among the very highest in the world, and our results show that the rate of deforestation is rapidly accelerating. This is especially concerning given the large number of species that are right on the brink of extinction already.  It is likely that without more intervention that many endangered species in Cambodia will go extinct. Stefan's article does a wonderful job of highlighting the role of flooded forest around the Tonle Sap, southeast Asia's largest inland lake, and the fact that it is rapidly being lost due to forest clearing increased wildfire. My hope is that Stefan's article will help wake people to the severity of the situation and help them realize what could be lost if we fail to take conservation action.

 The Wonders of the Mekong is a multidisciplinary collaborative project funded by USAID since 2016. Based in Cambodia, the project aims to maintain the ecological, cultural, and economic integrity of the vital Mekong river system through interdisciplinary research, capacity building, and education and outreach. More about the project can be found on Facebook (https://www.facebook.com/MekongWonders/), Instagram (https://www.instagram.com/mekongwonders/) and YouTube (https://www.youtube.com/mekongwonders).

Congratulations Sapana Lohani and team on the publication in the journal Water

Congratulations Sapani Lohani, Peter Weisberg, Sarah Null, and Zeb Hogan on a job well done!  Our paper "Rapidly Accelerating Deforestation in Cambodia’s Mekong River Basin: A Comparative Analysis of Spatial Patterns and Drivers" was just published today online in the journal Water, and you can view it by clicking HERE.  I'm really proud of the job that we did. This paper is part of a special edition in the journal Water that features a wide range of topics about the Lower Mekong. You can view the other papers in the special edition by clicking HERE. All of the papers in Water are open access so I'd encourage you to download them and read them.

Our analysis covered a time period from 1993 to 2017 and saw an accelerating rate of deforestation in Cambodia. This is notable because many tropical countries have seen a slowing of their deforestation rate (such as Brazil). In Cambodia, on the other hand, deforestation rates appear not just to be increasing, but to be rapidly accelerating. This has potential to lead to extinctions of forest-dependent species and may already be having an impact on nutrient cycling in aquatic systems. In our paper we studied four different geographic regions - the entire nation of Cambodia, Cambodia + Srepok, Sesan, and Sekong River Basins extending into Laos and Vietnam, just the Srepok, Sesan, and Sekong River Basin, and the area around the Tonle Sap Lake. We also examined forest loss in protected areas and community forests. We hope that our results will wake the world to the tremendous biodiversity loss that is occurring in this region and encourage land managers and policy makers to take stricter actions to reverse the loss of forests in this region.

The Wonders of the Mekong is a multidisciplinary collaborative project funded by USAID since 2016. Based in Cambodia, the project aims to maintain the ecological, cultural, and economic integrity of the vital Mekong river system through interdisciplinary research, capacity building, and education and outreach. More about the project can be found on Facebook (https://www.facebook.com/MekongWonders/), Instagram (https://www.instagram.com/mekongwonders/) and YouTube (https://www.youtube.com/mekongwonders).

Ali Urza's new paper on lower treelines is now typeset in Ecological Applications

Congratulations Ali Urza for a job well done on your paper " Evidence of widespread topoclimatic limitation for lower treelines of the Intermountain West, United States". It is great to see the article is now formatted for the journal!

https://esajournals.onlinelibrary.wiley.com/doi/abs/10.1002/eap.2158

Trick to select multiple datasets for batch processing in ArcMap

I recently rediscovered a handy little trick for multiple selecting multiple datasets. Most tools in ArcMap have one input and one output.  This trick doesn't apply to those tools.  However, there are tools such as Cell Statistics or Mosaic to New Raster or Mosaic that can take multiple inputs.  If you are finding yourself repeatedly hitting the "add data" button or dragging and dropping there is a solution that will save you time!

1.  Open Windows Explorer/My Computer if you are using a Window machine and navigate to the folder that you wish to search.  In this case I've got monthly rasters with each having the names _01.img, _02.img, etc. to denote January, February, etc.



2.  In the search window type in *_01.img or something similar to filter out all of the January files.  This will result in a whole slew of files, some that are the regular IMG file and others that XML files.

3.  Hold down the shift key and select all of the files including the XML files and drag them into the ArcMap Table of Contents.  One option that I recommend is to disable "make newly added layers visible" in ArcMap.  To disable this go to Customize --> ArcMap Options --> General --> and uncheck "make newly added layers visible".  This will make it quicker to load the layers in the Table of Contents in ArcMap without having to draw every layer.





4.  The layers will now all be shown in the Table of Contents in ArcMap.  The nice thing is that ArcMap knows not to try to add the XML file into the Table of Contents so you are left with just the image files.





5.  Open the cell statistics tool from ArcToolbox and select the statistic that you wish to have calculated (e.g. SUM, MEAN, etc.).  Shift select all of the layers that you want added and drag them in as input layers into the Cell Statistics tool.

The nice thing about this trick is that it is simple and requires no programming or Model Builder.