# What is the national map accuracy standard?

Table of Contents

## What is the national map accuracy standard?

As applied to the USGS 7.5-minute quadrangle topographic map, the hori- zontal accuracy standard requires that the positions of 90 percent of all points tested must be accurate within 1/50th of an inch (0.05 centimeters) on the map. At 1:24,000 scale, 1/50th of an inch is 40 feet (12.2 meters).

## How accurate are USGS maps?

Turns out, USGS topo maps use the National Map Accuracy Standards. This means that 90 percent of the horizontal points tested by field survey teams are accurate to within 40 feet. Vertical points, to within half a contour line, or five feet, based on standard 7.5 minute, 10-foot contour lines.

What is the positional accuracy of the topo map at the 90% confidence level?

The standard for topographic maps state that horizontal positions of 90 percent of the well-defined points tested will occur within 0.02 inches (map distance) of their actual positions.

What is the standard size of a USGS topographic map?

The size of printed 1:24,000-scale topographic maps distributed by the USGS can vary slightly depending on publication date and latitude. On average: US Topo maps (published after 2008) are 24″ wide x 29″ high. Historical topographic maps (published before 2008) are 22″ wide x 27″ high.

### How do you calculate mAP accuracy?

The mAP is calculated by finding Average Precision(AP) for each class and then average over a number of classes. The mAP incorporates the trade-off between precision and recall and considers both false positives (FP) and false negatives (FN). This property makes mAP a suitable metric for most detection applications.

### What are accuracy standards?

Accuracy is the degree of conformity with a standard or a measure of closeness to a true value. Accuracy relates to the quality of the result obtained when compared to the standard. The standard used to determine accuracy can be: • An exact value, such as the sum of the three angles of a plane triangle is 180 degrees.

What is a 7.5 topo map?

The most commonly used topo map covers 7.5 minutes, which equals 1/8th a degree of latitude and longitude. These maps are called the 7.5 Minute Series. Latitude lines are called parallels, which helps us remember that they are parallel to the equator.

How do you calculate positional accuracy?

It uses root-mean-square-error (RMSE) to estimate positional accuracy. RMSE is the square root of the average of the set of squared differences between dataset coordinate values and coordinate values from an independent source of higher accuracy.

#### Why is a 7.5 minute map not square?

These quadrangles are not squares because 7.5′ of longitude is a smaller distance in miles at 36° N (36th parallel) than 7.5 minutes of latitude. Nor are these quadrangles rectangles because the vertical sides, representing longitude lines (meridians), are not parallel.

#### How do you calculate K on a mAP?

Firstly, we need to compute the AP at an arbitrary threshold k of each dataset. Then, we simply sum up and find the mean of AP@k of every dataset to get the mAP@k.

What is a good mAP score object detection?

As a summary, the IoU score measures how close is the predicted box to the ground-truth box. It ranges from 0.0 to 1.0 where 1.0 is the optimal result. When the IoU is greater than the threshold, then the box is classified as Positive as it surrounds an object.

What is mAP accuracy?

The closeness of results of observations, computations, or estimates of graphic map features to their true value or position.

## Why is a USGS map commonly called a 7.5 minute quad?

Maps are typically named after prominent, local physiographic features, such as important peaks, rivers, valleys, etc. A map series is determined from how many minutes it covers, thus the 7.5-minute seriesbeing so named.

## What is positional accuracy in GIS?

Positional accuracy is the quantifiable value that represents the positional difference between two geospatial layers or between a geospatial layer and reality.

What is positional error in GIS?

Positional error is often of great concern in GIS, but error can actually affect many different characteristics of the information stored in a database. 3.1. Positional accuracy and precision. This applies to both horizontal and vertical positions.

What are the National Geospatial program standards and specifications?

National Geospatial Program (NGP) standards and specifications define the requirements to ensure that all The National Map products and data prepared by the USGS under the NGP are consistent in accuracy, structure, format, style, and content. Browse The National Map standards and specifications.

### What are NGP standards and specifications?

National Geospatial Program (NGP) standards and specifications define requirements to ensure that all maps and data prepared by NGP, in support of The National Map, are consistent in accuracy, structure, format, style, and content. What are standards and specifications? Is it a standard or is it a specification?

### What is the National Map?

Learn More! As one of the cornerstones of the U.S. Geological Survey’s (USGS) National Geospatial Program, The National Map is a collaborative effort among the USGS and other Federal, State, and local partners to improve and deliver topographic information for the Nation.

What is the USGS topographic maps Search and download app?

This is the primary search and download application for USGS topographic maps and base-layer GIS data. The same topographic maps are also downloadable through other interfaces.