# Documentation

True for points inside or on lat-lon quadrangle

## Syntax

`tf = ingeoquad(lat, lon, latlim, lonlim)`

## Description

`tf = ingeoquad(lat, lon, latlim, lonlim)` returns an array `tf` that has the same size as `lat` and `lon`. `tf(k)` is true if and only if the point `lat(k)`, `lon(k)` falls within or on the edge of the geographic quadrangle defined by `latlim` and `lonlim`. `latlim` is a vector of the form ```[southern-limit northern-limit]```, and `lonlim` is a vector of the form `[western-limit eastern-limit]`. All angles are in units of degrees.

## Examples

1. Load and display a digital elevation model (DEM) including the Korean Peninsula:

```korea = load('korea'); R = refvecToGeoRasterReference(korea.refvec, size(korea.map)); figure('Color','white') worldmap([20 50],[90 150]) geoshow(korea.map, R, 'DisplayType', 'texturemap'); demcmap(korea.map) ```

2. Outline the quadrangle containing the DEM:

```[outlineLat, outlineLon] = outlinegeoquad(R.Latlim, ... R.Lonlim, 90, 5); geoshow(outlineLat,outlineLon,'DisplayType','line', ... 'Color','black') ```
3. Generate a track that crosses the DEM:

```[lat, lon] = track2(23, 110, 48, 149, [1 0], 'degrees', 20); geoshow(lat, lon, 'DisplayType', 'line')```

4. Identify and mark points on the track that fall within the quadrangle outlining the DEM:

```tf = ingeoquad(lat, lon, R.Latlim, R.Lonlim); geoshow(lat(tf), lon(tf), 'DisplayType', 'point')```