Newbie: Measured Grid Problems

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05-26-2021 01:39 PM
KannaTenjo
New Contributor II

Hi, I'm trying to make a grid that is specifically made of 1km squares. However, there are 2 things I do not understand. 

1) Output Feature Class

KannaTenjo_0-1622061134438.png

What does this mean? Can you choose any name? If so, does it affect how the grid will show up? For now I've just been randomly typing things into it. 

2) Input Feature 

Now this was the real frustrating part. Currently the only features I can select from are the features that represent the red dots and/or the black squares. I can't get a way to tell the system that I want the grid all over the enclosed black frame (I've learned that's a graphic layer and therefore doesn't count as a 'feature', which I don't completely understand, but okay.) 

Thus, when I tried to make my grid....

KannaTenjo_1-1622061279542.png

the squares only show up near the red dots/black squares. 

I have also tried to make a feature set that has giant black squares essentially covering the area I want, and set it as an input, but that didn't work. 

 

Oh, and you know the little grid icon at the map's bottom? I tried setting that to 1km squares too, but those squares don't even show up at all. Invisible. Even when I zoom in. And yes I have checked the colour settings. Only when it's in 32 ft or something, then it shows, but that wouldn't work for my project. 

 

I have no idea what I'm doing wrong. Please help me; I've spent hours looking up tutorials but they seem to use a different format of Arcgis Pro or they don't explain thoroughly to me. Your help is appreciated. 

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8 Replies
DanPatterson
MVP Esteemed Contributor

What is your projection?  (it should be a projected coordinate system and not Web Mercator)

Why not create a fishnet as a polyline if you just want the outline of the grids

Create Fishnet (Data Management)—ArcGIS Pro | Documentation

 


... sort of retired...
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KannaTenjo
New Contributor II

I don't quite understand what you mean by 'projection'; please explain? But I shall try the fishnet.

"it should be a projected coordinate system and not Web Mercator" --> If you mean that I should have obtained the map from the program and not import the map from an external source, then that's what I did; the map is courtesy of Arcgis.

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DavidMurray_ODWC
New Contributor III

Ah. You are very new to GIS.

So, "Feature Classes" are the new type of file that stores/displays some geographic feature.  In your case, those are the layers you've named "dot," "okay," "sites," etc.  Usually a feature class contains things like "water fountain locations" or "roads."  Besides the graphical depiction of the locations, feature classes also contain an attribute table that store all sorts of values attributed to a particular feature.

It doesn't really matter what you name them.  It'd be best if it is something that makes sense.  I might name a linear feature class of trails in a park "P_Trails" and then create a buffered distance polygon feature class from the trails called "P_Trails_bffr30ft."  ArcGIS starts acting broken if you have any spaces in the path name or file name, so it's just best to avoid spaces.

"Projection" refers to the crazy math used to take what is an oblate spheroid (the planet earth) and display it in a 2-dimensional form (a map, or the PC screen).  Thankfully, very few of us actually have to deal with the math.  The default projection of ESRI Online maps use the "Web Mercator Auxiliary Sphere" spatial reference (also known as WKID 102100).  Here's ESRI's intro to the topis for ArcPro: https://pro.arcgis.com/en/pro-app/latest/help/mapping/properties/coordinate-systems-and-projections....

What you'll want to do is Reproject whatever Feature Classes will be involved in your analysis, as well as change the Map's projection.  https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/project.htm

Here's the list of Projected Coordinate Systems: https://pro.arcgis.com/en/pro-app/latest/help/mapping/properties/list-of-supported-map-projections.h...

You should choose one that's best for your project.  I'm partial to Albers.  Albers Equal Area Conformal Conic, USGS Version is used a lot in my office.

~So then, create a Fishnet, or Tessellation.

Also, you might want to create a new Feature Class, as a Polygon, and use the Edit tab to add it to your map as a substitute for that purely graphic black frame.

KannaTenjo
New Contributor II

My newness cannot be stated enough :) I'm learning it today. Thank you for the helpful resources; I'll try to wrap my head around it. I didn't know the thing about spaces; I'll avoid them in the future (no wonder it keeps glitching up), and I'll see about the fishnet/tessellation. Thank you again. I'll update you on if I get it to work.

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DavidMurray_ODWC
New Contributor III

Honestly, this seems a bit much for your first day.

Okay, the textbook GIS Fundamentals (6th edition) has a website though the book itself isn't freely available.
Instead, their links to the ArcGIS Pro lab exercises may be right up your alley!  I recommend reading/watching Labs 1-3 as soon as you can.  Then looking at your problem again.

A different source:
A short video about the Map Projection.
A nice wee video about the Projection Tool.
Creating a new [empty] feature class, followed by a new polygon.

 

As an alternative to the Create Fishnet tool, the Generate Tessellation tool has some extra benefits (I think).  <-Only ESRI sourced document in this post.

Good Luck! :four_leaf_clover:

KannaTenjo1
New Contributor II

Thank you for the resources!

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JayantaPoddar
MVP Esteemed Contributor

One more post. Just trying to get things easier for you with the help of screenshots.

You are right about the graphics layer. So first thing is we will create a shapefile or feature class, and draw a polygon on top of the graphics rectangle.

1. In Catalog pane > navigate to your project folder > right-click the File Geodatabase (*.gdb) > New > Feature Class.

JayantaPoddar_0-1622073056506.png

 

JayantaPoddar_1-1622073209583.png

Click Next until you reach Spatial Reference dialog. Ensure a coordinate system is selected/available (see screenshot below). Click Finish.

JayantaPoddar_2-1622073392465.png

The feature class is created (currently it's blank), and added to Content pane.

JayantaPoddar_3-1622073710243.png

 

2. Now let's create a polygon on top of the graphics, shall we?

Ensure the "Area of Interest" and the graphics layer are only checked in Contents pane. Uncheck the other layers.

Click on Edit tab > Create

JayantaPoddar_4-1622074085965.png

In Create Features pane, select the Area of Interest layer > Select Rectangle icon.

JayantaPoddar_5-1622074212243.png

JayantaPoddar_6-1622074528545.png

When prompted to save all edits, click Yes.

3. You may run Grid Index Features. 

JayantaPoddar_7-1622075027552.png

 

JayantaPoddar_8-1622075218524.png

 



Think Location
KannaTenjo1
New Contributor II

These screenshots helped immensely! Thank you!

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