prototype

Author: DanielJDufour

.gitignore

@@ -102,3 +102,5 @@ dist
 
 # TernJS port file
 .tern-port
+
+.DS_Store

README.md

@@ -1,2 +1,21 @@
 # is-geotiff
 Super Light and Fast Method for Checking if a TIFF is a GeoTIFF
+
+# install
+```bash
+npm install is-geotiff
+```
+
+# usage
+```js
+const fs = require("fs");
+const isGeoTIFF = require("is-geotiff");
+
+const buffer = fs.readFileSync("./example.tiff");
+
+const { result } = isGeoTIFF({
+    data: buffer,
+    debug: false // set debug to true for increased logging
+});
+// result is true
+```

data/cog.tif

@@ -0,0 +1,31 @@
+const hasBytes = require("has-bytes");
+
+const GEOTIFF_TAGS = {
+  GeoKeyDirectoryTag: [135, 175], // 0x87AF
+  ModelPixelScaleTag: [14, 131], // 0x830E
+  ModelTiepointTag: [130, 132], // 0x8482
+  GeoDoubleParamsTag: [176, 135], // 0x87B0
+  GeoAsciiParamsTag: [177, 135], // 0x87B1
+  GDAL_NODATA: [129, 164] // 0xA481
+};
+
+module.exports = ({
+  data,
+  debug = false,
+  read_length = 1000,
+  threshold = 3
+}) => {
+  if (debug) console.log("[is-geotiff] starting with data", data);
+
+  const { found, result } = hasBytes({
+    data,
+    debug,
+    end: read_length,
+    sequences: GEOTIFF_TAGS,
+    start: 0,
+    threshold
+  });
+  if (debug) console.log("[is-geotiff] result from hasBytes is", result);
+
+  return { found, result, threshold };
+};