Include resolution to Create Fishnet

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03-30-2020 12:26 PM
Status: Open
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AbelPerez
Occasional Contributor II

The Create Fishnet geoprocessing tool is great for producing grid feature classes. One thing I find that it lacks is a resolution parameter. With this parameter there will be intermediate vertices added to the polyline or polygon so that it doesn't look so blocky when a projected spatial reference is used for the map.

As an example I have created a 10 degree x 10 degree grid for North America and then changed the map spatial reference to North Polar Stereographic. Because the grid doesn't have any intermediate vertices the feature class appears blocky. Using a resolution of say 0.1 degrees would introduce vertices within each feature so as to make it smoother.

I think the logic to do this already exists in the Layout Grid function. If I go to my Layout and add a Grid and color it red you can see the difference.

9 Comments
DanPatterson_Retired

It sort of is offered as a two step process

  • produce the fishnet
  • geodesic densify

then project

Geodetic Densify—Data Management toolbox | Documentation 

AbelPerez

Just to confirm if I geodesic densify along a latitude or a longitude then the new vertices will lay on that latitude or longitude. ie if I have a polyline along the 80W longitude and I densify it geodesically then all new vertices will have an x=-80.

DanPatterson_Retired

give it whirl, you have the polylines

AbelPerez

No go. That tool is not available with a Basic License.

DanPatterson_Retired
AbelPerez

Excellent. I think I will add that piece with ArcObjects since I have used a densify function within ArcMap with no issues.

AbelPerez

So I did as you suggested. Used the Fishnet geoprocessing. Then after that I ran a Densify on each geometry. Seems to do the job.

AbelPerez

Here is the final product with Fishnet geoprocessing + ArcObjects Densify.

JustinGates

This is the only exchange where I saw this important piece of information, so thank you. I found the Geodetic Densify tool, but wasn’t sure if it was working, because the lines I’m dealing with are much shorter. But the theory matters in the long run I think. Here’s my story: downloaded public NASA DEM data for the nation of Nicaragua, had to create a mosaic to generate contours. Since the contour file is so big, had to consider tiling for rendering purposes. I wanted to tile the same as original data, could not find the index shapefile for original tiles anywhere. Figured out how to fishnet, using original DEM parameters, but measuring the interior angles showed 90deg exactly, so those are rectangles... in the WGS84 system. Not wrong mathematically, but a rectangle nonetheless. Soooo I want to Geodetic Densify those rectangles, with a max vertex equal to cell size of DEM, so that any future geoprocessing of surface data can be cut to those tiles, and will coincide with the original tiles (at least a reasonable facsimile thereof).  Am I out to lunch here?