Latest Contributions by zhongying_gan

‎09-08-2023

Hello, I'm using ArcGIS Pro 3.0.2. I want to compute the length of line features in mile. However, under Calculate Geometry Attribute, there is no unit called mile. There are multiple other types of mile, but after googling them, I think none of them is the mile that we commonly use in daily life. The screenshot is below: I was wondering if anyone could help me with this. Thank you.

‎07-27-2023

Hello, I'm using ArcGIS Pro 3.0.2. I would like to make a highway speed map that looks like the following: You can see that there are two parallel lines for each freeway, because there are always two directions. I have a line feature of California highway system in ArcGIS Pro. When zoom in, I can clearly see the freeways of two directions: But after I zoom out, the two-direction lanes just merge into one: I tried to make both lanes very thick, as shown in the first map (my goal), but the lines just overlap each other: I was wondering if there is a way for me to make both lines thick and repel each other so that they are not overlapping? Any comments will be greatly appreciated. Thank you.

‎06-09-2023

Hello, Thank you so much for your reply. I used the XY To Line geoprocessing tool, then changed the symbol to an arrow. Lastly, I used "vary symbology by attribute" option to vary the thickness of the line based on the size of the commute flow.

‎06-08-2023

Hello, I am currently using ArcGIS Pro 3.0.2. My dataset consists of residence census tract, workplace census tract, and the number of people who commute from the residence census tract to the workplace census tract. The following is an example of my dataset: residence_id workplace_id commute 0101 0203 50 0503 0602 20 I have a map of census tracts. I am looking for a way for ArcGIS Pro to draw arrows from the residence census tract to the workplace census tract, in this case, from tract 0101 to tract 0203, and from tract 0503 to tract 0602. The following is an illustration of what I would like to achieve: If possible, I was wondering how to make the size of the arrow proportional to the size of the commute flow. For example, since there are more people commuting from 0101 to 0203 than from 0503 to 0602, the arrow from 0101 to 0203 should be thicker than the arrow from 0503 to 0602. Any ideas will be greatly appreciated. Thank you!

‎01-23-2022

Hello Dan. Thank you for your reply. I projected the map layer onto the state plane projected coordinate system and it worked. Thank you so much.

‎01-22-2022

Hello Dan. Thank you for your reply. I used the Minimum Bounding Geometry tool and chose Convex hull as the geometric type. It does the job. One thing is that the MBG length is in a very weird unit. So I would like the distance to be measured in mile. A distance that should have been 0.6 mile is displayed as 0.009411 in ArcGIS Pro. https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/minimum-bounding-geometry.htm says that the distance unit is the unit of the feature. The spatial reference of the feature is gcs north american 1983. I read from here (https://gis.stackexchange.com/questions/166525/what-unit-is-the-shape-length-field-in-for-the-gcs-north-american-1983-csrs-proj) that the unit of measurement would be degrees. I was wondering whether you know how I could transform the distance unit from degree to mile. Because you know it's not like from meter to mile where I just multiply it by a scalar. Thank you.

‎01-21-2022

Hello. I'm using ArcGIS Pro 2.9.0. I have more than 6,000 census block groups (polygons in ArcGIS Pro) and I would like to compute the longest radius in each of them. I attached a picture to illustrate what the longest radius is. I would really appreciate it if you could let me know how I could accomplish it. Thank you.

‎11-02-2021

Hello, I'm using ArcGIS Pro 2.8.3. I want to find all the points that are within one mile radius of a polygon, and I would like to know what the distances is, so I use "generate near table" option. The parameter I used is in the attached screenshot. I thought that since I use 1 mile as the search radius, the NEAR_DIST in the output table would be in the unit of mile too. But this is not the case. When I use geodesic distance, NEAR_DIST ranges from 0 to 1602.7, so I guess the unit is meter. When I use planar distance, NEAR_DIST ranges from 0 to 0.0144, and I'm not sure what unit it is. My question is, how can I make NEAR_DIST take mile as the unit at the very beginning? Also, can I add a new field, and let it equal to NEAR_DIST, but in the unit of mile? Thank you.

‎11-01-2021

Hello. I'm using arcgis pro 2.8.3. The pink part in the image attached is a geodatabase of census block groups of LA county. I want to find all the block groups that are on the boundary/border of this map. I know one option would be to eyeball which polygons lie on the border and manually select them. But I was wondering whether there are any commands/analysis tools that I may use in this case. Thank you for your help.

‎10-04-2021

Hello, I am using ArcGIS Pro 2.8.3. I have a shapefile of census blocks of LA county. I also have a layer of buffers. I want to find buffers that lay completely within the boundary of LA county. So I use select by location--> completely within. However, this command gives me only the buffers that lie completely within any individual census block, instead of within the entire LA county. I try to go to edit-->merge to merge all the census blocks into one, so that I have one polygon of LA county. No matter whether I use "Existing Feature" or "New feature", I always receive the error message: merge features failure. the spatial index grid size is invalid. I was wondering whether anyone could help me with this. Thank you.

‎08-20-2021

Thank you. It worked!

‎08-20-2021

Hello. I'm using ArcGIS Pro 2.8.2. I have a layer of census block (polygon layer 1). And I have another layer of the center point latitude and longitude of the census blocks (point layer). I use this point layer to generate circular buffer area of one mile around the center points (polygon layer 2). Now I want to determine whether for each census block, it completely lies within its buffer area. For example, in buffer_polygon.png, the census block does not lie completely within its circular buffer area of one mile. I was wondering which tool I should use and which steps I should take to determine whether for each census block, it completely lies within its buffer area. Thank you.

‎08-19-2021

Hello Dan. Thank you for your reply. I have tried typing "import arcpy", but it didn't work. Please refer to the error message in the screenshot attached under my question. Thank you.

‎08-19-2021

Hello. I'm currently using arcgis pro 2.8.2. I go to "Analysis"-->"Python"-->"Python window". And I typed the following code in the screenshot, but I got the error message that "name arcpy not defined" (arcpy_not_defined.png). This is weird because I have read instructions saying that if you use python window within arcgis, you don't need to import arcpy. Even when I import arcpy, it does not work. I was wondering if anyone has any idea what is going on. Thank you.

‎08-11-2021

Hello. My arcgis pro version is 2.8.2. I didn't use the link @Deborah_Priss mentioned. I installed Python following the steps on https://community.esri.com/t5/arcgis-pro-blog/installing-spyder-ide-for-arcpro/bc-p/1088109#M369. Then I started it via the anaconda navigator by changing the "Applications on" field to my cloned arcpy environment.

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My Ideas

Latest Contributions by zhongying_gan

Calculate Geometry Attribute-unable to use mile as unit

Make line features thick and yet not overlapping

Re: generate arrows indicating commute flows from one census tract to another on ArcGIS Pro

generate arrows indicating commute flows from one census tract to another on ArcGIS Pro

Re: Compute the longest radius in a polygon

Re: Compute the longest radius in a polygon

Compute the longest radius in a polygon

Generate near table-unexpected distance unit

How to identify polygons on the boundary

select by location--> completely within does not work as intended

Re: How to decide whether a polygon lies completely within another polygon

How to decide whether a polygon lies completely within another polygon

Re: Unable to use arcpy in Python window within arcgis pro

Unable to use arcpy in Python window within arcgis pro

Re: what python editors do you use for arcpy

Make line features thick and yet not overlapping

what python editors do you use for arcpy

Re: Installing spyder IDE for ArcPro

Re: how to check what geometry I have used to comp...