#TESSELLATION DEFINITION ARCGIS HOW TO#
#TESSELLATION DEFINITION ARCGIS UPDATE#
#TESSELLATION DEFINITION ARCGIS FULL#
#TESSELLATION DEFINITION ARCGIS CODE#

format ( size = w / 3 * h / 3, unit = u ) # Use the extent's spatial reference to project the output spatial_ref = extent. Syntax (Output_Feature_Class, Extent, s'.

To create a grid that excludes tessellation features that do not intersect features in another dataset, use the Select Layer By Location tool to select output polygons that contain the source features and use the Copy Features tool to make a permanent copy of the selected output features to a new feature class.

For example, select all features in column A with GRID_ID like 'A-%', or select all features in row 1 with GRID_ID like '%-1'. This allows for easy selection of rows and columns using queries in the Select Layer By Attribute tool. Some special kinds include regular tilings with regular. A periodic tiling has a repeating pattern. In mathematics, tessellation can be generalized to higher dimensions and a variety of geometries. The format for the IDs is A-1, A-2, B-1, B-2, and so on. A tessellation or tiling is the covering of a surface, often a plane, using one or more geometric shapes, called tiles, with no overlaps and no gaps. The GRID_ID field provides a unique ID for each feature in the output feature class.

The output features contain a GRID_ID field. This occurs because the edges of the tessellated grid will not always be straight lines and gaps would be present if the grid was limited by the input extent. This is the consistent area of the polygons in the result whether I generate square or hex polygons. The output is NOT a set of polygons with area1 sq mile, but rather area 0.092903 sq miles (2589988.8 sq feet). To ensure the entire input extent is covered by the tessellated grid, the output features purposely extend beyond the input extent. I generated a tessellation using the extent of the County boundary and specifying a size of 1 square mile. The tessellation can be of triangles, squares, or hexagons. meshes.Generates a polygon feature class of a tessellated grid of regular polygons which will entirely cover a given extent. Note that the width parameter is a pure number, and the tessellate Polyline()method does not make any assumption with regard to the units being used from now on, we will assume that width is in pixels, but a better option would be using points or some other screen-space length unit.Įach graphic becomes a promise in the this.promises array each promise resolves to an object that contains the resulting mesh as well as the attribute and symbol objects of the original graphic, effectively binding together the mesh and all the information that may determine its appearance on screen.įor ( let meshIndex = 0 meshIndex < this. For instance a width attribute of the graphics can be passed as the width parameter of tessellate Polyline() method.

#TESSELLATION DEFINITION ARCGIS CODE#

In the following code snippets we focus on the polyline case, but the other cases are analogous.Īttributes from the graphic can be used to drive the values of the other parameters of the tessellate*()method of choice. The geometry type determines which tessellate*() method is called to create the mesh.

#TESSELLATION DEFINITION ARCGIS UPDATE#

When done, all the meshes are saved to the meshes member variable and the entire layer view is marked as dirty by setting needs Update to true, meaning the collection of meshes has changed but they have not been uploaded to the GPU for rendering.Įach graphic is converted to a mesh by a call to process Graphic(). In the attach() method of the custom layer view a listener is set up that will fire for any change to the graphic collection when a change is detected all the graphics are reprocessed using the custom method this.process Graphic() each call to this.process Graphic() creates a promise that resolves when the mesh for that graphic has been created. Every time that the graphics change, the layerview will reprocess all the graphics and recreate all the meshes. The custom layer is a subclass of GraphicsLayer.

The update Positions() method in the original sample has been modified to convert the geometry of any graphic into triangle meshes these meshes have special per-vertex attributes that the shader program uses to render any geometry type. These helpers methods allow the developer to create triangle meshes for any geometry type, including polylines and polygons. This sample instead uses the new tessellate*() methods implemented by BaseLayerViewGL2D. It is similar to the Custom WebGL layer view sample, which triangulates points into quads. This description assumes familiarity with WebGL and custom WebGL layer views.

#TESSELLATION DEFINITION ARCGIS FULL#

It can be used as the starting point for complex visualizations where the developer has full control of the rendering process.

#TESSELLATION DEFINITION ARCGIS HOW TO#

This sample demonstrates how to render graphics using a custom WebGL layer view.

This sample targets expert developers familiar with WebGL and hardware-accelerated rendering.

This sample shows experimental functionality, please read the documentation carefully before using it in a product.

Tessellation definition arcgis